Relationship of circulating tumor necrosis factor alpha (TNF-alfa) and insulin secretion and resistance in euglycaemic dogs

Background: Insulin resistance is a state that is characterized with reduced sensitivity of peripheral tissues to insulin. Itcan be related with increased level of tumor necrosis factor alpha (TNF-α) in dogs. Insulin resistance can be evaluated byhomeostasis model assessment (HOMA-IR, HOMA-β). The aim of this study was to determine correlation of circulatingTNF-α level with insulin production and insulin resistance indexes in euglycaemic dogs.Materials, Methods & Results: Seventy dogs of normal body score were included in this study. After blood sampling levelsof glucose, insulin and TNF-α were determined and indexes HOMA-IR and HOMA-β were calculated. Three groups inaccordance to TNF-α levels were formed: the first-TNF-α 0-2.0 pg/mL, the second-TNF-α below median (2.1-17.0 pg/mL)and the third-TNF-α above median (17.1-51.8 pg/mL). Differences in insulin and glucose levels, HOMA-IR and HOMA-βwere determined in all three groups. ANOVA and posthock LSD analyses were used. Correlation between HOMA-IR andHOMA-β was determined. Linear regression between HOMA-β/HOMA-IR ratio and glucose concentration was calculated. SPSS statistical program was used (IBM). Highest insulin level was detected in the second group and the lowest wasdetected in the third group. The lowest glucose level was detected in the first group. The highest value of HOMA-β indexwas noted in the first group and it decreases with TNF-α increase. The highest HOMA-IR value was detected in the secondgroup and the lowest was in the third group. Positive correlation was noted between HOMA-IR and HOMA-β. Significantlinear correlation was noted between glucose levels in function of HOMA-β/HOMA-IR...

Relationship of circulating tumor necrosis factor alpha (TNF-alfa) and insulin secretion and resistance in euglycaemic dogs

Background: Insulin resistance is a state that is characterized with reduced sensitivity of peripheral tissues to insulin. Itcan be related with increased level of tumor necrosis factor alpha (TNF-α) in dogs. Insulin resistance can be evaluated byhomeostasis model assessment (HOMA-IR, HOMA-β). The aim of this study was to determine correlation of circulatingTNF-α level with insulin production and insulin resistance indexes in euglycaemic dogs.Materials, Methods & Results: Seventy dogs of normal body score were included in this study. After blood sampling levelsof glucose, insulin and TNF-α were determined and indexes HOMA-IR and HOMA-β were calculated. Three groups inaccordance to TNF-α levels were formed: the first-TNF-α 0-2.0 pg/mL, the second-TNF-α below median (2.1-17.0 pg/mL)and the third-TNF-α above median (17.1-51.8 pg/mL). Differences in insulin and glucose levels, HOMA-IR and HOMA-βwere determined in all three groups. ANOVA and posthock LSD analyses were used. Correlation between HOMA-IR andHOMA-β was determined. Linear regression between HOMA-β/HOMA-IR ratio and glucose concentration was calculated. SPSS statistical program was used (IBM). Highest insulin level was detected in the second group and the lowest wasdetected in the third group. The lowest glucose level was detected in the first group. The highest value of HOMA-β indexwas noted in the first group and it decreases with TNF-α increase. The highest HOMA-IR value was detected in the secondgroup and the lowest was in the third group. Positive correlation was noted between HOMA-IR and HOMA-β. Significantlinear correlation was noted between glucose levels in function of HOMA-β/HOMA-IR...(AU)

Markers of inflammation and insulin resistance in dogs before and after weight loss versus lean healthy dogs / Marcadores de inflamação e resistência à insulina em cães antes e depois da perda de peso versus cães saudáveis e magros

Chronic low-grade inflammation in obesity is characterized by an increased production of pro-inflammatory cytokines that contribute to insulin resistance. For this study body composition, markers of inflammation and of insulin resistance in dogs before and after weight loss were compared to those of lean dogs. Eleven client-owned obese adult dogs underwent a weight loss program with commercial dry food for weight loss and reached an ideal body condition score (BCS) six months after the beginning of the weight loss program. A Control Group of nine dogs with ideal BCS were selected for the comparison. Shapiro-Wilk test was used to test for normality, Mann Whitney were used for non-normally distributes data, and Student t-test was used for normally distributed parameters. In the Obese Group body fat decreased from 41.6% (30.7-58.6) to 29.1% (18.6-46.3) (P<0.01) and dogs maintained lean body mass throughout the weight loss program (P>0.05). Obese dogs presented higher concentration of fructosamine, triglycerides, insulin, IGF-1 and leptin than the Control Group before weight reduction (P<0.05). Serum concentrations of triglycerides, IL-2, IL-6, TNF-α, insulin, leptin and IGF-1 decreased after weight loss (P<0.01), and these concentrations were similar to the Control Group (P>0.05), except for leptin (P<0.001). No alteration on peptide YY was found. Leptin (r=0.60, P=0.01), fructosamine (r=0.44, P=0.02) and triglycerides (r=0.40, P=0.04) concentrations correlated with the reduction of body fat. Weight loss reduced the concentrations of inflammatory and insulin resistance markers and most parameters became similar to dogs that have always been lean, reinforcing the importance of weight loss in small animal practice.(AU)

A inflamação crônica de baixo grau na obesidade é caracterizada pela produção aumentada de citocinas pró-inflamatórias que contribuem para a resistência à insulina. Para este estudo a composição corporal e os marcadores de inflamação e de resistência à insulina em cães antes e após a perda de peso foram comparados aos de cães magros. Onze cães adultos obesos pertencentes a tutores foram incluídos em um programa de perda de peso com ração comercial hipocalórica e alcançaram escore de condição corporal (ECC) ideal seis meses após o início do regime. Um Grupo Controle de nove cães com ECC ideal foi selecionado para a comparação. O teste de Shapiro-Wilk foi usado para testar a normalidade, Mann Whitney foi usado para análise dos dados que não atenderam distribuição normal e o teste t de Student foi usado para parâmetros que atenderam a normalidade. No Grupo Obesidade, a gordura corporal diminuiu de 41,6% (30,7-58,6) para 29,1% (18,6-46,3) (P<0,01) e os cães mantiveram massa magra ao longo do programa de perda de peso (P>0,05). Cães obesos apresentaram maior concentração de frutosamina, triglicérides, insulina, IGF-1 e leptina do que o Grupo Controle antes da redução de peso (P<0,05). As concentrações séricas de triglicerídeos, IL-2, IL-6, TNF-α, insulina, leptina e IGF-1 diminuíram após a perda de peso (P<0,01) e, essas concentrações foram semelhantes ao Grupo Controle (P>0,05), com exceção da leptina (P<0,001). Nenhuma alteração no peptídeo YY foi encontrada. As concentrações de leptina (r=0,60; P=0,01), frutosamina (r=0,44; P=0,02) e triglicerídeos (r=0,40; P=0,04) correlacionaram-se com a redução da gordura corporal. A perda de peso reduziu as concentrações de marcadores inflamatórios e de resistência à insulina e a maioria dos parâmetros tornaram-se semelhante aos dos cães que sempre foram magros, reforçando a importância da perda de peso na prática clínica de pequenos animais.(AU)

Markers of inflammation and insulin resistance in dogs before and after weight loss versus lean healthy dogs / Marcadores de inflamação e resistência à insulina em cães antes e depois da perda de peso versus cães saudáveis e magros

Chronic low-grade inflammation in obesity is characterized by an increased production of pro-inflammatory cytokines that contribute to insulin resistance. For this study body composition, markers of inflammation and of insulin resistance in dogs before and after weight loss were compared to those of lean dogs. Eleven client-owned obese adult dogs underwent a weight loss program with commercial dry food for weight loss and reached an ideal body condition score (BCS) six months after the beginning of the weight loss program. A Control Group of nine dogs with ideal BCS were selected for the comparison. Shapiro-Wilk test was used to test for normality, Mann Whitney were used for non-normally distributes data, and Student t-test was used for normally distributed parameters. In the Obese Group body fat decreased from 41.6% (30.7-58.6) to 29.1% (18.6-46.3) (P<0.01) and dogs maintained lean body mass throughout the weight loss program (P>0.05). Obese dogs presented higher concentration of fructosamine, triglycerides, insulin, IGF-1 and leptin than the Control Group before weight reduction (P<0.05). Serum concentrations of triglycerides, IL-2, IL-6, TNF-α, insulin, leptin and IGF-1 decreased after weight loss (P<0.01), and these concentrations were similar to the Control Group (P>0.05), except for leptin (P<0.001). No alteration on peptide YY was found. Leptin (r=0.60, P=0.01), fructosamine (r=0.44, P=0.02) and triglycerides (r=0.40, P=0.04) concentrations correlated with the reduction of body fat. Weight loss reduced the concentrations of inflammatory and insulin resistance markers and most parameters became similar to dogs that have always been lean, reinforcing the importance of weight loss in small animal practice.(AU)

A inflamação crônica de baixo grau na obesidade é caracterizada pela produção aumentada de citocinas pró-inflamatórias que contribuem para a resistência à insulina. Para este estudo a composição corporal e os marcadores de inflamação e de resistência à insulina em cães antes e após a perda de peso foram comparados aos de cães magros. Onze cães adultos obesos pertencentes a tutores foram incluídos em um programa de perda de peso com ração comercial hipocalórica e alcançaram escore de condição corporal (ECC) ideal seis meses após o início do regime. Um Grupo Controle de nove cães com ECC ideal foi selecionado para a comparação. O teste de Shapiro-Wilk foi usado para testar a normalidade, Mann Whitney foi usado para análise dos dados que não atenderam distribuição normal e o teste t de Student foi usado para parâmetros que atenderam a normalidade. No Grupo Obesidade, a gordura corporal diminuiu de 41,6% (30,7-58,6) para 29,1% (18,6-46,3) (P<0,01) e os cães mantiveram massa magra ao longo do programa de perda de peso (P>0,05). Cães obesos apresentaram maior concentração de frutosamina, triglicérides, insulina, IGF-1 e leptina do que o Grupo Controle antes da redução de peso (P<0,05). As concentrações séricas de triglicerídeos, IL-2, IL-6, TNF-α, insulina, leptina e IGF-1 diminuíram após a perda de peso (P<0,01) e, essas concentrações foram semelhantes ao Grupo Controle (P>0,05), com exceção da leptina (P<0,001). Nenhuma alteração no peptídeo YY foi encontrada. As concentrações de leptina (r=0,60; P=0,01), frutosamina (r=0,44; P=0,02) e triglicerídeos (r=0,40; P=0,04) correlacionaram-se com a redução da gordura corporal. A perda de peso reduziu as concentrações de marcadores inflamatórios e de resistência à insulina e a maioria dos parâmetros tornaram-se semelhante aos dos cães que sempre foram magros, reforçando a importância da perda de peso na prática clínica de pequenos animais.(AU)

Insulin dysregulation in horses with induced obesity / Desregulação da insulina em equinos com obesidade induzida

Insulin deregulation (ID) is a central player in the pathophysiology of equine metabolic syndrome (EMS), which is associated with generalized and/or regional obesity. The objective of this experiment was to characterize the alterations in the hormonal profile in horses exposed to a hypercaloric diet. A total of nine Mangalarga Marchador adult horses with initial body condition score (BCS) of 2.9±1/9 (mean±SD) were submitted to a high calorie grain-rich diet for 5 months. The data was collected before the start of the experiment and every 15 days until the end of the experiment and glucose and insulin concentrations were measured in the plasma. Proxies G:I, RISQI, HOMA-IR and MIRG were calculated. The low-dose oral glucose tolerance test (OGTT) was performed and the total area under the glucose (GTA) and insulin (ITA) curves at three different timepoints (before inducing obesity, after 90 days and after 150 days) was used. Analysis of variance of the results was performed considering the time effects and the means were compared with repeated measures by the Tukey's test (P≤0.05). The ID was observed during the first 90 days of the experiment and was characterized as a decompensated ID, showing an increase of basal glucose and insulin plasma levels, changes in all proxies and a significant increase in GTA (P<0.001) and ITA (P<0.05). However, a clear compensation of the ID was evident after 150 days of experiment, which was supported by data from the insulin secretory response of ß cells of the pancreas that showed an increase in insulin plasma levels, after fasting or exposure to gastric glucose, with a concomitant decrease in fasting glucose and fructosamine levels, and a decrease of GTA and marked increase of ITA (P<0.0001) in the dynamic test. These findings confirm the occurrence of hyperinsulinemia associated with insulin deregulation in Mangalarga Marchador horses exposed to hypercaloric diets.(AU)

A desregulação insulínica (DI) é o ponto central dos mecanismos fisiopatológicos da síndrome metabólica equina (SME), que é associada à obesidade generalizada e/ou regional. O objetivo deste experimento foi caracterizar as alterações no perfil hormonal em equinos submetidos à dieta hipercalórica. Foram utilizados nove equinos Mangalarga Marchador adultos com escore corporal (EC) médio (±DP) inicial de 2,9±1 (escala de 1-9) submetidos à dieta hipercalórica atingindo um EC de 8,3±1 após cinco meses. Os dados foram coletados antes do início do experimento e com o intervalo de 15 dias até o final do experimento, os valores plasmáticos foram obtidos para mensuração das concentrações de glicose e insulina. Foram calculados os proxies G:I, RISQI, HOMA-IR e o MIRG. Foi realizado o teste de baixa dose de glicose oral (TBDGO) utilizando a área total sob a curva de glicose (ATG) e insulina (ATI) em três momentos, antes da indução a obesidade, após 90 e 150 dias. Os resultados foram submetidos à análise de variância considerando-se os efeitos de tempo e as médias comparadas com medidas repetidas pelo teste de Tukey, com o valor P≤0,05. A DI foi observada nos primeiros 90 dias de experimento, se caracterizando como um quadro de DI descompensada, apresentando um aumento dos níveis plasmáticos basais de glicose e insulina, pelas alterações em todos os proxies e com um aumento significativo da ATG (P<0,001) e ATI (P<0,05). Contudo, ficou evidente uma compensação do quadro de DI após 150 dias de experimento, sendo demonstrado pelos dados da resposta secretória insulínica das células ß do pâncreas, que se manifestaram pelo aumento dos níveis plasmáticos de insulina pós-jejum ou exposição à glicose gástrica com concomitante redução nos níveis de glicose e frutosamina pós-jejum e pela redução da ATG e pela marcada elevação de ATI (P<0,0001) no teste dinâmico. Tais achados comprovam a ocorrência de hiperinsulinemia associada à desregulação insulínica em equinos Mangalarga Marchador expostos a dietas à dieta hipercalórica.(AU)

Insulin dysregulation in horses with induced obesity / Desregulação da insulina em equinos com obesidade induzida

Insulin deregulation (ID) is a central player in the pathophysiology of equine metabolic syndrome (EMS), which is associated with generalized and/or regional obesity. The objective of this experiment was to characterize the alterations in the hormonal profile in horses exposed to a hypercaloric diet. A total of nine Mangalarga Marchador adult horses with initial body condition score (BCS) of 2.9±1/9 (mean±SD) were submitted to a high calorie grain-rich diet for 5 months. The data was collected before the start of the experiment and every 15 days until the end of the experiment and glucose and insulin concentrations were measured in the plasma. Proxies G:I, RISQI, HOMA-IR and MIRG were calculated. The low-dose oral glucose tolerance test (OGTT) was performed and the total area under the glucose (GTA) and insulin (ITA) curves at three different timepoints (before inducing obesity, after 90 days and after 150 days) was used. Analysis of variance of the results was performed considering the time effects and the means were compared with repeated measures by the Tukey's test (P≤0.05). The ID was observed during the first 90 days of the experiment and was characterized as a decompensated ID, showing an increase of basal glucose and insulin plasma levels, changes in all proxies and a significant increase in GTA (P<0.001) and ITA (P<0.05). However, a clear compensation of the ID was evident after 150 days of experiment, which was supported by data from the insulin secretory response of ß cells of the pancreas that showed an increase in insulin plasma levels, after fasting or exposure to gastric glucose, with a concomitant decrease in fasting glucose and fructosamine levels, and a decrease of GTA and marked increase of ITA (P<0.0001) in the dynamic test. These findings confirm the occurrence of hyperinsulinemia associated with insulin deregulation in Mangalarga Marchador horses exposed to hypercaloric diets.(AU)

A desregulação insulínica (DI) é o ponto central dos mecanismos fisiopatológicos da síndrome metabólica equina (SME), que é associada à obesidade generalizada e/ou regional. O objetivo deste experimento foi caracterizar as alterações no perfil hormonal em equinos submetidos à dieta hipercalórica. Foram utilizados nove equinos Mangalarga Marchador adultos com escore corporal (EC) médio (±DP) inicial de 2,9±1 (escala de 1-9) submetidos à dieta hipercalórica atingindo um EC de 8,3±1 após cinco meses. Os dados foram coletados antes do início do experimento e com o intervalo de 15 dias até o final do experimento, os valores plasmáticos foram obtidos para mensuração das concentrações de glicose e insulina. Foram calculados os proxies G:I, RISQI, HOMA-IR e o MIRG. Foi realizado o teste de baixa dose de glicose oral (TBDGO) utilizando a área total sob a curva de glicose (ATG) e insulina (ATI) em três momentos, antes da indução a obesidade, após 90 e 150 dias. Os resultados foram submetidos à análise de variância considerando-se os efeitos de tempo e as médias comparadas com medidas repetidas pelo teste de Tukey, com o valor P≤0,05. A DI foi observada nos primeiros 90 dias de experimento, se caracterizando como um quadro de DI descompensada, apresentando um aumento dos níveis plasmáticos basais de glicose e insulina, pelas alterações em todos os proxies e com um aumento significativo da ATG (P<0,001) e ATI (P<0,05). Contudo, ficou evidente uma compensação do quadro de DI após 150 dias de experimento, sendo demonstrado pelos dados da resposta secretória insulínica das células ß do pâncreas, que se manifestaram pelo aumento dos níveis plasmáticos de insulina pós-jejum ou exposição à glicose gástrica com concomitante redução nos níveis de glicose e frutosamina pós-jejum e pela redução da ATG e pela marcada elevação de ATI (P<0,0001) no teste dinâmico. Tais achados comprovam a ocorrência de hiperinsulinemia associada à desregulação insulínica em equinos Mangalarga Marchador expostos a dietas à dieta hipercalórica.(AU)

Insulin dysregulation in horses with induced obesity

ABSTRACT: Insulin deregulation (ID) is a central player in the pathophysiology of equine metabolic syndrome (EMS), which is associated with generalized and/or regional obesity. The objective of this experiment was to characterize the alterations in the hormonal profile in horses exposed to a hypercaloric diet. A total of nine Mangalarga Marchador adult horses with initial body condition score (BCS) of 2.9±1/9 (mean±SD) were submitted to a high calorie grain-rich diet for 5 months. The data was collected before the start of the experiment and every 15 days until the end of the experiment and glucose and insulin concentrations were measured in the plasma. Proxies G:I, RISQI, HOMA-IR and MIRG were calculated. The low-dose oral glucose tolerance test (OGTT) was performed and the total area under the glucose (GTA) and insulin (ITA) curves at three different timepoints (before inducing obesity, after 90 days and after 150 days) was used. Analysis of variance of the results was performed considering the time effects and the means were compared with repeated measures by the Tukeys test (P0.05). The ID was observed during the first 90 days of the experiment and was characterized as a decompensated ID, showing an increase of basal glucose and insulin plasma levels, changes in all proxies and a significant increase in GTA (P 0.001) and ITA (P 0.05). However, a clear compensation of the ID was evident after 150 days of experiment, which was supported by data from the insulin secretory response of cells of the pancreas that showed an increase in insulin plasma levels, after fasting or exposure to gastric glucose, with a concomitant decrease in fasting glucose and fructosamine levels, and a decrease of GTA and marked increase of ITA (P 0.0001) in the dynamic test. These findings confirm the occurrence of hyperinsulinemia associated with insulin deregulation in Mangalarga Marchador horses exposed to hypercaloric diets.

RESUMO: A desregulação insulínica (DI) é o ponto central dos mecanismos fisiopatológicos da síndrome metabólica equina (SME), que é associada à obesidade generalizada e/ou regional. O objetivo deste experimento foi caracterizar as alterações no perfil hormonal em equinos submetidos à dieta hipercalórica. Foram utilizados nove equinos Mangalarga Marchador adultos com escore corporal (EC) médio (±DP) inicial de 2,9±1 (escala de 1-9) submetidos à dieta hipercalórica atingindo um EC de 8,3±1 após cinco meses. Os dados foram coletados antes do início do experimento e com o intervalo de 15 dias até o final do experimento, os valores plasmáticos foram obtidos para mensuração das concentrações de glicose e insulina. Foram calculados os proxies G:I, RISQI, HOMA-IR e o MIRG. Foi realizado o teste de baixa dose de glicose oral (TBDGO) utilizando a área total sob a curva de glicose (ATG) e insulina (ATI) em três momentos, antes da indução a obesidade, após 90 e 150 dias. Os resultados foram submetidos à análise de variância considerando-se os efeitos de tempo e as médias comparadas com medidas repetidas pelo teste de Tukey, com o valor P0,05. A DI foi observada nos primeiros 90 dias de experimento, se caracterizando como um quadro de DI descompensada, apresentando um aumento dos níveis plasmáticos basais de glicose e insulina, pelas alterações em todos os proxies e com um aumento significativo da ATG (P 0,001) e ATI (P 0,05). Contudo, ficou evidente uma compensação do quadro de DI após 150 dias de experimento, sendo demonstrado pelos dados da resposta secretória insulínica das células do pâncreas, que se manifestaram pelo aumento dos níveis plasmáticos de insulina pós-jejum ou exposição à glicose gástrica com concomitante redução nos níveis de glicose e frutosamina pós-jejum e pela redução da ATG e pela marcada elevação de ATI (P 0,0001) no teste dinâmico. Tais achados comprovam a ocorrência de hiperinsulinemia associada à desregulação insulínica em equinos Mangalarga Marchador expostos a dietas à dieta hipercalórica.

The relationship between insulin resistance and type II ketosis in dairy cows

Background: Cows in perinatal period are prone to ketosis, characterized by increased ketone bodies and decreased bloodsugar. Study found that cows with type II ketosis had higher blood glucose levels. This type of ketosis exhibits insulinresistance and impaired glucose tolerance that are similar to type 2 diabetes. The purpose of this study was to investigatethe role of insulin resistance(IR) in type II ketosis in dairy cows.Materials, Methods & Results: In one intensive cattle farm, eight cows with ketosis and eight healthy cows that were 14-21 days postpartum were selected. The plasma of experimental dairy cows was collected and tested for the concentrationof glucose concentration. Glucose tolerance of blood glucose levels in 120 min was used as the cut-off point to divide thedairy cows into three groups: the abnormal glucose tolerance ketosis group (TH), the normal glucose tolerance ketosis(TL), and the healthy control group. Simultaneously, the indexes of plasma liver function, oxidative stress, and insulinresistance were detected. The results showed that after intravenous glucose injection, there was no significant differencein blood glucose concentration between the TL and control group, while the blood glucose levels in the TH group werealways higher than in the other two groups. The insulin sensitivity index (RQUICKI) value was significantly lower in theTH group than in the other two groups. Liver function abnormalities in the TH group were more severe than in the TL andcontrol group. Oxidative stress was higher in the TH group than in the TL and control groups...

The relationship between insulin resistance and type II ketosis in dairy cows

Background: Cows in perinatal period are prone to ketosis, characterized by increased ketone bodies and decreased bloodsugar. Study found that cows with type II ketosis had higher blood glucose levels. This type of ketosis exhibits insulinresistance and impaired glucose tolerance that are similar to type 2 diabetes. The purpose of this study was to investigatethe role of insulin resistance(IR) in type II ketosis in dairy cows.Materials, Methods & Results: In one intensive cattle farm, eight cows with ketosis and eight healthy cows that were 14-21 days postpartum were selected. The plasma of experimental dairy cows was collected and tested for the concentrationof glucose concentration. Glucose tolerance of blood glucose levels in 120 min was used as the cut-off point to divide thedairy cows into three groups: the abnormal glucose tolerance ketosis group (TH), the normal glucose tolerance ketosis(TL), and the healthy control group. Simultaneously, the indexes of plasma liver function, oxidative stress, and insulinresistance were detected. The results showed that after intravenous glucose injection, there was no significant differencein blood glucose concentration between the TL and control group, while the blood glucose levels in the TH group werealways higher than in the other two groups. The insulin sensitivity index (RQUICKI) value was significantly lower in theTH group than in the other two groups. Liver function abnormalities in the TH group were more severe than in the TL andcontrol group. Oxidative stress was higher in the TH group than in the TL and control groups...(AU)

Equine metabolic syndrome in Colombian creole horse: case report / Síndrome metabólica equina em cavalo crioulo Colombiano: relato de caso

The equine metabolic syndrome is a condition that can be recognized because of obesity, insulin resistance and laminitis. Genetic factors could play a role in the occurrence of this syndrome. Certain breeds such as ponies (including the South American creole horses) have a lower sensibility to insulin and a higher prevalence of hyperinsulinemia. The environment and management conditions, such as overfeeding and lack of exercise are factors that bring a propensity for obesity. The adipose tissue works as an endocrine organ producing hormones (adipokines or adipocytokines) that affect the horse´s metabolism. The objective of this report is to describe the first case report of a Colombian creole mare with a metabolic syndrome, diagnosed by means of the combined test of glucose-insulin and clinical signs. Early diagnosis of this entity and an adequate treatment are useful for improving the life and the zootechnical conditions of the patient.(AU)

A síndrome metabólica equina é uma alteração reconhecida por apresentar obesidade, resistência à insulina e laminite. Fatores genéticos poderiam ser relevantes na ocorrência dessa síndrome, em que certas raças consideradas pôneis (incluídas as raças crioulas de cavalos sul-americanos) têm mais baixa sensibilidade à insulina e mais alta prevalência de apresentar hiperinsulinemia. As condições ambientais e de manejo, como superalimentação e falta de exercício, são fatores predisponentes para o desenvolvimento da obesidade. O tecido adiposo cumpre atividades como um órgão endócrino produtor de hormônios (adipocinas ou adipocitocinas) que afetam o metabolismo do cavalo. O objetivo deste relatório é descrever o primeiro registro de caso de uma égua de raça Cavalo Crioulo Colombiano (CCC) com síndrome metabólica, diagnosticada pela prova combinada de glicose-insulina e por quadro clínico. O diagnóstico precoce desta entidade e seu tratamento adequado permitem melhorar as condições de vida e zootécnicas do paciente que dela padece.(AU)

Equine metabolic syndrome in Colombian creole horse: case report / Síndrome metabólica equina em cavalo crioulo Colombiano: relato de caso

The equine metabolic syndrome is a condition that can be recognized because of obesity, insulin resistance and laminitis. Genetic factors could play a role in the occurrence of this syndrome. Certain breeds such as ponies (including the South American creole horses) have a lower sensibility to insulin and a higher prevalence of hyperinsulinemia. The environment and management conditions, such as overfeeding and lack of exercise are factors that bring a propensity for obesity. The adipose tissue works as an endocrine organ producing hormones (adipokines or adipocytokines) that affect the horse´s metabolism. The objective of this report is to describe the first case report of a Colombian creole mare with a metabolic syndrome, diagnosed by means of the combined test of glucose-insulin and clinical signs. Early diagnosis of this entity and an adequate treatment are useful for improving the life and the zootechnical conditions of the patient.(AU)

A síndrome metabólica equina é uma alteração reconhecida por apresentar obesidade, resistência à insulina e laminite. Fatores genéticos poderiam ser relevantes na ocorrência dessa síndrome, em que certas raças consideradas pôneis (incluídas as raças crioulas de cavalos sul-americanos) têm mais baixa sensibilidade à insulina e mais alta prevalência de apresentar hiperinsulinemia. As condições ambientais e de manejo, como superalimentação e falta de exercício, são fatores predisponentes para o desenvolvimento da obesidade. O tecido adiposo cumpre atividades como um órgão endócrino produtor de hormônios (adipocinas ou adipocitocinas) que afetam o metabolismo do cavalo. O objetivo deste relatório é descrever o primeiro registro de caso de uma égua de raça Cavalo Crioulo Colombiano (CCC) com síndrome metabólica, diagnosticada pela prova combinada de glicose-insulina e por quadro clínico. O diagnóstico precoce desta entidade e seu tratamento adequado permitem melhorar as condições de vida e zootécnicas do paciente que dela padece.(AU)

Combinação de butafosfan e cianocobalamina no metabolismo da glicose em vacas leiteiras após o parto / Combined of butaphosphan and cyanocobalamin on the glucose metabolism of dairy cows after calving

A hipótese deste estudo é de que o uso da combinação de butafosfan e cianocobalamina pode melhorar a resistência periférica à insulina, aumentar a quantidade de glicose disponível para a glândula mamária e a produção de leite. Assim, o objetivo foi investigar os efeitos combinados de butafosfan e cianocobalamina sobre o metabolismo da glicose em vacas leiteiras no período pós-parto. Vinte e uma vacas leiteiras foram divididas em dois grupos: grupo controle (CON, n= 11), que recebeu cinco aplicações de solução salina (20mL / animal 0,9% NaCl), e grupo Catosal(r) (ABC, n= 10), que recebeu cinco aplicações de 20mL de uma solução contendo as substâncias butafosfan e cianocobalamina (B12 Catosal(r), 100mg da substância butafosfan e 50µg de cianocobalamina por mL). As aplicações foram realizadas por via intramuscular, nos dias sete, 12, 17, 22 e 27 pós-parto. As amostras de sangue foram coletadas para a avaliação das concentrações plasmáticas de fósforo, glicose, ácidos graxos não esterificados (AGNE), albumina, aspartato aminotransferase (AST) e creatina quinase (CK). Nos dias oito e 28 pós-parto, os animais foram pesados e submetidos aos testes de tolerância à glicose e à insulina. O tratamento promoveu perda de peso (ABC 40,4kg, CON 10,73kg, P<0,05) e aumento da AST (ABC 62,92 ±3,31U/L, CON 53,11±3,49 U / L, P<0,05) e dos níveis de CK (ABC 134,09± 19,08U / L, CON 79,43 ± 18,27U / L). Os grupos não diferiram quanto ao metabolismo (área sob a curva) da glicose nos dias oito e 28, porém os animais tratados tiveram um aumento na glicemia (P<0,05) no dia 28 pós-parto (97,54 ± 8,54mg / dL), após a administração de insulina, em comparação ao dia oito (83,01 ± 8,54mg / dL). Assim, pode-se concluir que a combinação de butafosfan e cianocobalamina melhora a adaptação do metabolismo da glicose em vacas leiteiras no início da lactação.(AU)

The hypothesis of this study is that the combined use of butaphosphan and cyanocobalamin could enhance peripheral insulin resistance, increasing the amount of glucose available for the mammary gland and milk production. Thus, our aim was to investigate the combined effects of butaphosphan and cyanocobalamin on the glucose metabolism in dairy cows during the postpartum period. Twenty one dairy cows were divided into two groups: Control Group (CON, n= 11), that received 5 injections of saline solution (20mL/animal 0.9 % NaCl), and Catosal group (ABC, n= 10) which received 5 injections of 20mL of a Butafosfan and Cyanocobalamin solution (Catosal(r) B12, 100mg of Butafosfan and 50µg Cyanocobalamin for mL). The injections were performed by intramuscular route, on days 7, 12, 17, 22 and 27 postpartum. Blood samples were taken on these days to evaluate plasma concentrations of phosphorus, glucose, non-esterified fatty acids (NEFA), albumin, aspartate aminotransferase (AST) and creatine kinase (CK). On days 8 and 28 postpartum, the animals were weighted and subjected to the glucose tolerance and insulin challenge tests. The treatment promoted weight loss (ABC 40.4kg, CON 10.73kg, P< 0.05) and increased AST (ABC 62.92 ±3.31U/L, CON 53.11 ±3.49U/L, P< 0.05) and CK levels (ABC 134.09 ±19.08U/L, CON 79.43 ±18.27U/L). Glucose metabolism (area under the curve) did not differ (P> 0.05) among groups on days 8 and 28; however, ABC animals showed higher serum glucose levels (P< 0.05) after insulin administration on day 28 postpartum (97.54 ±8.54mg/dL) when compared to day 8 (83.01 ±8.54mg/dL). It could be concluded that the combined use of butaphosphan and cyanocobalamin interferes positively with the adaptation of glucose metabolism in dairy cows in early lactation.(AU)

Combinação de butafosfan e cianocobalamina no metabolismo da glicose em vacas leiteiras após o parto / Combined of butaphosphan and cyanocobalamin on the glucose metabolism of dairy cows after calving

A hipótese deste estudo é de que o uso da combinação de butafosfan e cianocobalamina pode melhorar a resistência periférica à insulina, aumentar a quantidade de glicose disponível para a glândula mamária e a produção de leite. Assim, o objetivo foi investigar os efeitos combinados de butafosfan e cianocobalamina sobre o metabolismo da glicose em vacas leiteiras no período pós-parto. Vinte e uma vacas leiteiras foram divididas em dois grupos: grupo controle (CON, n= 11), que recebeu cinco aplicações de solução salina (20mL / animal 0,9% NaCl), e grupo Catosal(r) (ABC, n= 10), que recebeu cinco aplicações de 20mL de uma solução contendo as substâncias butafosfan e cianocobalamina (B12 Catosal(r), 100mg da substância butafosfan e 50µg de cianocobalamina por mL). As aplicações foram realizadas por via intramuscular, nos dias sete, 12, 17, 22 e 27 pós-parto. As amostras de sangue foram coletadas para a avaliação das concentrações plasmáticas de fósforo, glicose, ácidos graxos não esterificados (AGNE), albumina, aspartato aminotransferase (AST) e creatina quinase (CK). Nos dias oito e 28 pós-parto, os animais foram pesados e submetidos aos testes de tolerância à glicose e à insulina. O tratamento promoveu perda de peso (ABC 40,4kg, CON 10,73kg, P<0,05) e aumento da AST (ABC 62,92 ±3,31U/L, CON 53,11±3,49 U / L, P<0,05) e dos níveis de CK (ABC 134,09± 19,08U / L, CON 79,43 ± 18,27U / L). Os grupos não diferiram quanto ao metabolismo (área sob a curva) da glicose nos dias oito e 28, porém os animais tratados tiveram um aumento na glicemia (P<0,05) no dia 28 pós-parto (97,54 ± 8,54mg / dL), após a administração de insulina, em comparação ao dia oito (83,01 ± 8,54mg / dL). Assim, pode-se concluir que a combinação de butafosfan e cianocobalamina melhora a adaptação do metabolismo da glicose em vacas leiteiras no início da lactação.(AU)

The hypothesis of this study is that the combined use of butaphosphan and cyanocobalamin could enhance peripheral insulin resistance, increasing the amount of glucose available for the mammary gland and milk production. Thus, our aim was to investigate the combined effects of butaphosphan and cyanocobalamin on the glucose metabolism in dairy cows during the postpartum period. Twenty one dairy cows were divided into two groups: Control Group (CON, n= 11), that received 5 injections of saline solution (20mL/animal 0.9 % NaCl), and Catosal group (ABC, n= 10) which received 5 injections of 20mL of a Butafosfan and Cyanocobalamin solution (Catosal(r) B12, 100mg of Butafosfan and 50µg Cyanocobalamin for mL). The injections were performed by intramuscular route, on days 7, 12, 17, 22 and 27 postpartum. Blood samples were taken on these days to evaluate plasma concentrations of phosphorus, glucose, non-esterified fatty acids (NEFA), albumin, aspartate aminotransferase (AST) and creatine kinase (CK). On days 8 and 28 postpartum, the animals were weighted and subjected to the glucose tolerance and insulin challenge tests. The treatment promoted weight loss (ABC 40.4kg, CON 10.73kg, P< 0.05) and increased AST (ABC 62.92 ±3.31U/L, CON 53.11 ±3.49U/L, P< 0.05) and CK levels (ABC 134.09 ±19.08U/L, CON 79.43 ±18.27U/L). Glucose metabolism (area under the curve) did not differ (P> 0.05) among groups on days 8 and 28; however, ABC animals showed higher serum glucose levels (P< 0.05) after insulin administration on day 28 postpartum (97.54 ±8.54mg/dL) when compared to day 8 (83.01 ±8.54mg/dL). It could be concluded that the combined use of butaphosphan and cyanocobalamin interferes positively with the adaptation of glucose metabolism in dairy cows in early lactation.(AU)

Laminite associada à síndrome metabólica equina: revisão sistemática dos fatores de risco e eventos fisiopatológicos

A laminite é definida como afecção podal caracterizada por perda na integridade da conexão entre lâmina dérmica e epidérmica e é a segunda maior causa de óbito em equinos. A de maior ocorrência é a denominada laminite endocrinopática, a qual é marcada pela resistência à insulina dos tecidos ou hiperinsulinemia e pode ser causada pela síndrome metabólica equina (SME) ou disfunção da pars intermedia da pituitária (PPID). O objetivo desta revisão foi determinar evidências sobre os fatores de risco envolvidos no desenvolvimento da laminite associada à SME. A estratégia de busca foi realizada utilizando os termos laminitis, syndrome metabolic e equidae em sete bases de dados. Os principais critérios de elegibilidade foram estudos incluindo avaliação dos fatores de risco para a ocorrência de laminite associada a SME e descartaram disfunção da pars intermedia da pituitária nos animais avaliados. Foram encontrados 688 estudos, com 383 duplicados e excluídos. Trezentos e cindo estudos passaram por avaliação do título e resumo. A primeira seleção incluiu 85 artigos para leitura na íntegra e destes apenas 37 atenderam aos critérios de elegibilidade e foram incluídos neste estudo. Não foram encontradas evidências suficientes para determinar raça, sexo e idade como fatores de risco para laminite associada a SME. Dois estudos confirmaram o desenvolvimento da laminite a partir da indução por hiperinsulinemia. Oito estudos apresentaram evidências fortes da associação entre a concentração de insulina basal maior em animais laminíticos comparado aos não laminíticos. A obesidade foi associada a episódios de laminite em 6 estudos, encontrando também evidências de hipertrigliceridemia e hipoadponectinemia em animais laminíticos e obesos. A hiperinsulinemia na laminite endocrinopática associada à SME é o principal fator de risco desencadeante das diversas vias fisiopatológicas que ocorrem simultaneamente causando alterações no tecido laminar, confirmando mais uma vez seu papel na patogênese da doença. A obesidade se apresenta como um fator de risco por exacerbar a resistência à insulina, tornando o controle de peso e dos níveis de insulina imprescindíveis para prevenção da laminite endocrinopática. A ausência de um segundo avaliador na seleção dos estudos e a quantidade baixa de estudos epidemiológicos de laminite endocrinopática foram as principais limitações encontradas pelos autores. Esta é a primeira revisão sistemática realizada sobre o tema em questão.

Laminitis is defined as a foot disease characterized by loss in the integrity of the connection between the dermal and epidermal lamina and is the second leading cause of death in horses. The one with the highest occurrence is called endocrinopathic laminitis, which is marked by tissue insulin resistance or hyperinsulinemia and can be caused by equine metabolic syndrome (EMS) or pituitary pars intermedia dysfunction (PPID). The purpose of this review was to determine evidence on the risk factors involved in the development of laminitis associated with EMS. The search strategy was performed using the terms laminitis, metabolic syndrome, and equidae in seven databases. The main eligibility criteria were studies including evaluation of risk factors for the occurrence of EMS-associated laminitis and ruled out dysfunction of the pars intermedia of the pituitary in the evaluated animals. A total of 688 studies were found, with 383 duplicates excluded. Three hundred and five studies were reviewed for title and abstract. The first selection included 85 articles for reading in full and of these only 37 met the eligibility criteria and were included in this study. There was insufficient evidence to determine race, sex and age as risk factors for EMS laminitis. Two studies confirmed the development of laminitis from hyperinsulinemia induction. Eight studies showed strong evidence of the association between higher basal insulin concentration in laminitic animals compared to non-laminitic animals. Obesity was associated with episodes of laminitis in 6 studies, also finding evidence of hypertriglyceridemia and hypoadponectinemia in laminitic and obese animals. Hyperinsulinemia in endocrinopathic laminitis associated with EMS is the main risk factor triggering the various pathophysiological pathways that occur simultaneously causing changes in laminar tissue, confirming once again its role in the pathogenesis of the disease. Obesity is a risk factor for exacerbating insulin resistance, making weight and insulin levels control essential for prevention of endocrinopathic laminitis. The absence of a second reviewer in the selection of studies and the low number of epidemiological studies of endocrinopathic laminitis were the main limitations found by the authors. This is the first systematic review performed on the topic in question.

Experimental model of glucocorticoid-induced insulin resistance

PURPOSE:To evaluate metabolic effects in experimental model of glucocorticoid-induced insulin resistance.METHODS:Twenty Wistar male rats were randomly divided into two groups, which were treated with intraperitoneally injected dexamethasone 1mg/Kg/day for ten days consecutively (Group D; n=10) and placebo (Group C; n=10). The variables analyzed were: from the first to the 10th day - body weight (before and after treatment); food and water daily consumption; on the 10th day - glycemia, insulinemia, HOMA-beta and HOMA-IR. The blood samples for laboratory analysis were obtained by intracardiac puncture. Also on the 10th day liver fragments were taken for analyzing glycogen and fattty.RESULTS:Group D animals compared to group C had: weight reduction (g), (D=226.5±24.7 vs C=295.0±25.4; p=0.001); increased glycemia (mmol/l) (D=19.5±2.1 vs C=14.2±3.1; p=0.0001); diminished insulinemia (mU/l) (D=0.2±0.1 vs C=2.0±0.4; p=0.0001); reduced HOMA-β (D=0.2±0.1 vs C=4.2±1.7; p=0.0002); diminished HOMA-IR (D=0.2±0.1 vs C=1.3±0.4; p=0.0002). Histological examination of the liver showed that 100% of group D and none of group C had moderate fatty. (p=0.2).CONCLUSION:Animals treated with glucocorticoid, in this experimental model, expressed hyperglycemia, hypoinsulinism and decreased peripheral insulin sensitivity.(AU)

Parâmetros metabólicos, inflamatórios e de saciedade de gatos obesos alimentados com dieta com adição de beta-glucanos

RISOLIA, L.W. Parâmetros metabólicos, inflamatórios e de saciedade de gatos obesos alimentados com dieta com adição de beta-glucanos. 2021. 104 f. Tese (Doutorado em Ciências) Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 2021. Beta-glucanos são polissacarídeos que podem melhorar diversas alterações metabólicas e de saciedade consequentes à obesidade. O objetivo do presente estudo foi avaliar os efeitos da inclusão de 0,06% de beta-glucanos na dieta de gatos obesos em parâmetros do metabolismo de carboidratos e lipídeos, indicadores de resistência insulínica, citocinas inflamatórias, parâmetros de saciedade e coeficiente de digestibilidade aparente (CDA) dos nutrientes. Nove gatos diagnosticados com obesidade não-induzida [(grupo obeso OB) escore de condição corporal (ECC) 8-9 /9] e nove gatos não obesos [(Grupo controle CO) ECC 5/9] foram alimentados por 15 dias (T0) com a dieta controle (0,0% de beta-glucanos) e depois por 90 dias (T90) com a dieta teste (0,06% de beta-glucanos). Amostras de sangue foram coletadas em T0 e T90 para avaliação do índice HOMA (insulina basal x glicemia basal/22,5), concentrações plasmáticas de triglicerídeos, colesterol e lipoproteínas (por método enzimático-colorimétrico e cromatografia líquida para separação rápida de proteínas FPLC), anandamida (por ELISA), frutosamina (por ensaio colorimétrico cinético), amilina, interleucina 10 (IL-10), grelina e peptídeo semelhante ao glucagon 1 (GLP-1) (por reação em cadeia de polimerase em tempo real quantitativo). A composição corporal também foi avaliada no início e final do estudo pelo método de diluição de isótopos de deutério. Foram utilizados sete gatos do centro de pesquisa para a determinação do CDA das dietas, pelo método de coleta total de fezes. Para avaliar a comparação entre os grupos e o efeito da dieta foi realizado teste de ANOVA com medidas repetidas no tempo. Quando houve diferença entre as médias foi realizado o teste de Tukey. Para a análise de consumo de beta-glucanos, digestibilidade e resultados da análise de expressão gênica, os dados foram analisados por análise de variância e, valores de P<0,05 foram considerados significativos. O grupo CO consumiu mais beta-glucanos do que o OB e em T90, foi observado aumento de massa muscular em CO e OB sem alteração da gordura corporal. Não houve diferença nas concentrações de frutosamina e anandamida entre os grupos antes e após o consumo da dieta Teste. O grupo OB apresentou maior concentração de colesterol e triglicerídeos em VLDL (%; mg/dL), maior índice HOMA e maior concentração de insulina do que o CO, independente da dieta. O grupo CO apresentou maior concentração de triglicérides em LDL (%; mg/dL) e em HDL (%), independente da dieta. Em T0, o grupo CO apresentou maior concentração de colesterol total (TCOL) do que o OB. Em T90, o grupo OB apresentou aumento de TCOL e em LDL (%; mg/dL) além de redução de colesterol em HDL. Não houve variação na expressão gênica de amilina, GLP-1, grelina e IL-10 entre os grupos. A inclusão de beta-glucano não alterou o CDA dos nutrientes após o consumo do alimento Teste pelos dois grupos. Concluise que com a dose utilizada no presente estudo, o consumo de beta-glucanos não proporciona melhora dos parâmetros do metabolismo de carboidratos, lipídeos, inflamação, saciedade e não altera o CDA dos nutrientes.

RISOLIA, L.W. Metabolic, inflammatory and satiety parameters of obese cats fed a diet with the addition of beta glucans. 2021. 104 f. Tese (Doutorado em Ciências) Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 2020. Beta-glucans are polysaccharides capable of improving many satiety and metabolic alterations related to obesity. The aim of the present study was to evaluate the effects of the addition of 0.06% of beta-glucans in the diet of obese cats in parameters of carbohidrates and lipids metabolism, insuin resistance indicators, pro-inflamatory citokines, satiety parameters and nutrients aparent digestibility coefficient (ADC). For that, nine client owned cats with non induced obesity [(obese group - OB) body condition score (BCS) 8-9/9] and nine client owned lean cats [(Control Group - CO) BCS 5/9] were fed for 15 days (T0) with a control diet (0,0% of beta-glucans) and then for 90 days (T90) with a test diet (0.06% of beta-glucans). Blood samples were collected at T0 and T90 in order to evaluate the HOMA index (basal insulin x basal glucose/22.5), triglycerides, cholesterol and lipoproteins (through enzymatic - colorimetric method and fast protein liquid chromatography - FLPC), anandamide (through ELISA), fructosamine (through kinetic colorimetric assay), amylin, interleukin 10 (IL-10), ghrelin and glucagon-like peptide-1 (GLP-1) (through quantitative real time polymerase chain reaction). The body composition was also evaluated at the beginning and at the end of the study through deuterium isotope dilution technique. The ADC test was carried out with 7 cats from the research center through total feces collection. In order to evaluate the comparison between the groups, a repeated measures ANOVA test was performed. When differences between the averages occurred, the Tukey test was run. For the beta-glucans consumption, digestibility and gene expression results analysis, the data were analyzed through the variance analysis. The CO group consumed more beta-glucans than the OB and at T90 it was observed muscle mass (MM) gain in CO and OB without any change in body fat. There wasn't any difference in fructosamine and anandamide between the groups before and after the consumption of the experimental diet. The OB group presented more cholesterol and triglycerides in VLDL (%; mg/dL), HOMA index and insulin than in CO, regardless of the diet. The CO group presented more triglycerides in LDL (%; mg/dL) and in HDL (%), regardless of the diet. At T0, the CO group had more total cholesterol than the OB group. At T90, the OB group showed an increase in total and LDL cholesterol (%; mg/dL) in addition to a reduction in HDL cholesterol. There was no variation in amylin, GLP-1, ghrelin and IL-10, nor in the nutrient CDA after consumption of beta-glucans. It is concluded that with the dose used in this study, the consumption of beta-glucans does not improve the parameters of carbohydrate metabolism, lipids, inflammation, satiety and does not change the ADC of nutrients.

Insulin binding characteristics in canine muscle tissue: effects of the estrous cycle phases / Características de ligação da insulina no tecido muscular canino: efeitos da fase do ciclo estral

Hormonal fluctuations during the different estrous cycle are a well-recognized cause of insulin resistance in bitches, and little is known about insulin receptor binding or post-binding defects associated with insulin resistance in dogs. To evaluate insulin binding characteristics in muscle tissue of bitches during the estrous cycle, 17 owned bitches were used in the study (six in anestrus, five in estrus, and six in diestrus). An intravenous glucose tolerance test (IVGTT) was performed in all patients by means of injection of 1mL/kg of a glucose 50% solution (500mg/kg), with blood sample collection for glucose determination at 0, 3, 5, 7, 15, 30, 45 and 60 minutes after glucose infusion. Muscle samples, taken after spaying surgery, were immediately frozen in liquid nitrogen and then stored at -80 ºC until the membranes were prepared by sequential centrifugation after being homogenized. For binding studies, membranes were incubated in the presence of 20,000cpm of human 125I-insulin and in increasing concentrations of unlabeled human regular insulin for cold saturation. The IVGTT showed no differences among bitches during the estrous cycle regarding baseline glycemia or glycemic response after glucose infusion. Two insulin binding sites - high-affinity and low-affinity ones - were detected by Scatchard analysis, and significant statistical differences were observed in the dissociation constant (Kd1) and maximum binding capacity (Bmax1) of the high-affinity binding sites. The Kd1 for the anestrus group (6.54±2.77nM/mg of protein) was smaller (P<0.001) than for the estrus (28.54±6.94nM/mg of protein) and diestrus (15.56±3.88nM/mg of protein) groups. Bmax1 in the estrus (0.83±0.42nM/mg of protein) and diestrus (1.24±0.24nM/mg of protein) groups were also higher (P<0.001) than the values observed in anestrus (0.35±0.06nM/mg of protein). These results indicate modulation of insulin binding characteristics during different phases of the estrous cycle in dogs, showing that muscle insulin binding affinity for its receptor is reduced during estrus and diestrus. However, this poor hormone-receptor affinity is compensated for by a greater total binding capacity, once there is no difference in patients' glycemic response after an intravenous glucose load.(AU)

As flutuações hormonais durante as diferentes fases do ciclo estral são uma causa importante de resistência insulínica em fêmeas caninas, e poucas informações são conhecidas sobre defeitos na ligação da insulina ao seu receptor, ou defeitos pós-receptor associados com resistência à insulina em cães. Para avaliar as características da ligação insulina-receptor no tecido muscular de cadelas durante o ciclo estral, dezessete pacientes foram utilizadas no estudo (seis em anestro, cinco em estro e seis em diestro). Um teste de tolerância à glicose intravenosa (IVGTT) foi realizado em todas as pacientes por meio da infusão de 1mL/kg de uma solução de glicose 50% (500mg/kg), com coletas de sangue para determinação de glicemia nos tempos 0, 3, 5, 7, 15, 30, 45 e 60 minutos da injeção de glicose. Amostras de tecido muscular foram coletadas durante ovariohisterectomia, imediatamente congeladas em nitrogênio líquido, e posteriormente armazenadas a -80°C até a preparação das membranas por meio de homogeneização e centrifugação sequencial. Para os experimentos de ligação hormônio-receptor, as membranas foram incubadas na presença de 20.000cpm de 125I-insulina humana, e concentrações crescentes de insulina regular humana não marcada para saturação fria. O IVGTT não mostrou diferenças entre as pacientes em diferentes fases do ciclo estral com relação a glicemia basal, ou na resposta glicêmica após infusão de glicose nos tempos estudados. Dois sítios de ligação da insulina, um de alta-afinidade, e outro de baixa afinidade, foram detectados pela análise de Scatchard, e diferenças significativas foram detectadas na constante de dissociação (Kd1) e capacidade de ligação máxima (Bmax1) dos sítios de ligação de alta-afinidade. O Kd1 para o grupo anestro (6,54±2,77nM/mg de proteína) foi menor (P<0,001) que os Kd1 dos grupos estro (28,54±6,94 nM/mg de proteína) e diestro (15,56±3,88nM/mg de proteína). Os Bmax1 dos grupos estro (0,83±0,42nM/mg de proteína) e diestro (1,24±0,24nM/mg de proteína) também foram maiores que os valores encontrados no grupo anestro (0,35±0,06nM/mg de proteína). Estes resultados demonstram uma modulação das características de ligação da insulina nas diferentes fases do ciclo estral em cães, evidenciando uma menor afinidade de ligação da insulina ao seu receptor no tecido muscular durante o estro e diestro. Contudo, esta menor afinidade de ligação hormônio-receptor é compensada por uma maior capacidade de ligação, o que fica também evidenciado pela ausência de diferenças na resposta glicêmica das pacientes após um desafio com glicose por via endovenosa.(AU)

Insulin binding characteristics in canine muscle tissue: effects of the estrous cycle phases / Características de ligação da insulina no tecido muscular canino: efeitos da fase do ciclo estral

Hormonal fluctuations during the different estrous cycle are a well-recognized cause of insulin resistance in bitches, and little is known about insulin receptor binding or post-binding defects associated with insulin resistance in dogs. To evaluate insulin binding characteristics in muscle tissue of bitches during the estrous cycle, 17 owned bitches were used in the study (six in anestrus, five in estrus, and six in diestrus). An intravenous glucose tolerance test (IVGTT) was performed in all patients by means of injection of 1mL/kg of a glucose 50% solution (500mg/kg), with blood sample collection for glucose determination at 0, 3, 5, 7, 15, 30, 45 and 60 minutes after glucose infusion. Muscle samples, taken after spaying surgery, were immediately frozen in liquid nitrogen and then stored at -80 ºC until the membranes were prepared by sequential centrifugation after being homogenized. For binding studies, membranes were incubated in the presence of 20,000cpm of human 125I-insulin and in increasing concentrations of unlabeled human regular insulin for cold saturation. The IVGTT showed no differences among bitches during the estrous cycle regarding baseline glycemia or glycemic response after glucose infusion. Two insulin binding sites - high-affinity and low-affinity ones - were detected by Scatchard analysis, and significant statistical differences were observed in the dissociation constant (Kd1) and maximum binding capacity (Bmax1) of the high-affinity binding sites. The Kd1 for the anestrus group (6.54±2.77nM/mg of protein) was smaller (P<0.001) than for the estrus (28.54±6.94nM/mg of protein) and diestrus (15.56±3.88nM/mg of protein) groups. Bmax1 in the estrus (0.83±0.42nM/mg of protein) and diestrus (1.24±0.24nM/mg of protein) groups were also higher (P<0.001) than the values observed in anestrus (0.35±0.06nM/mg of protein). [...] (AU)

As flutuações hormonais durante as diferentes fases do ciclo estral são uma causa importante de resistência insulínica em fêmeas caninas, e poucas informações são conhecidas sobre defeitos na ligação da insulina ao seu receptor, ou defeitos pós-receptor associados com resistência à insulina em cães. Para avaliar as características da ligação insulina-receptor no tecido muscular de cadelas durante o ciclo estral, dezessete pacientes foram utilizadas no estudo (seis em anestro, cinco em estro e seis em diestro). Um teste de tolerância à glicose intravenosa (IVGTT) foi realizado em todas as pacientes por meio da infusão de 1mL/kg de uma solução de glicose 50% (500mg/kg), com coletas de sangue para determinação de glicemia nos tempos 0, 3, 5, 7, 15, 30, 45 e 60 minutos da injeção de glicose. Amostras de tecido muscular foram coletadas durante ovariohisterectomia, imediatamente congeladas em nitrogênio líquido, e posteriormente armazenadas a -80°C até a preparação das membranas por meio de homogeneização e centrifugação sequencial. Para os experimentos de ligação hormônio-receptor, as membranas foram incubadas na presença de 20.000cpm de 125I-insulina humana, e concentrações crescentes de insulina regular humana não marcada para saturação fria. O IVGTT não mostrou diferenças entre as pacientes em diferentes fases do ciclo estral com relação a glicemia basal, ou na resposta glicêmica após infusão de glicose nos tempos estudados. Dois sítios de ligação da insulina, um de alta-afinidade, e outro de baixa afinidade, foram detectados pela análise de Scatchard, e diferenças significativas foram detectadas na constante de dissociação (Kd1) e capacidade de ligação máxima (Bmax1) dos sítios de ligação de alta-afinidade. O Kd1 para o grupo anestro (6,54±2,77nM/mg de proteína) foi menor (P<0,001) que os Kd1 dos grupos estro (28,54±6,94 nM/mg de proteína) e diestro (15,56±3,88nM/mg de proteína).[...] (AU)

Insulin resistance in different physiological states of high producing Holstein dairy cows

Background: Alterations in energy demands during different physiological states of dairy cows predispose them to metabolic disorders. Insulin as a main metabolic hormone has a key role to maintain homeorhesis in dairy cows. Insulin resistance phenomenon can expose these animals to metabolic dysfunctions. Information regarding insulin resistance at each physiological state of high producing dairy cows can assist veterinarians to control and prevent the metabolic disorders at herd levels.Materials, Methods & Results: This research was carried out at winter 2014 on 25 multiparous Holstein dairy cows from a high producing industrial dairy farm. The total mixed rations were formulated and prepared for all animals according to National Research Council (NRC) requirements. At this farm, a dry period of 60 days has been considered. Milk production was about 10,000 kg for year, an average of 3.6 of milk fat %, and 3.3 of milk protein %. All the animals were clinically healthy and body condition score (BCS) was estimated based on 0 to 5 system. Cattle were divided into 5 equal groups containing early, mid and late lactations, far-off and close-up dry periods. A blood sample was taken immediately after catheterization, and dextrose 50% was administered at 500 mg/kg, 10 mL/kg/h, subsequently. Blood samples were collected from all cows through the fixed catheter prior to and 1, 2, 3 and 4 h after dextrose 50% infusion in plain tubes. After sera separation, glucose and insulin were detected in all samples. Significant and rapid elevation of serum glucose and insulin concentrations were seen in all studied animals at 1st h after dextrose administration (P < 0.05). Decreasing the glucose level near to base line levels was seen at h 4 in late lactation and far-off dry cows. The glucose level at this time was remained significantly higher than h zero in other groups (P < 0.05).[...](AU)

Insulin resistance in different physiological states of high producing Holstein dairy cows

Background: Alterations in energy demands during different physiological states of dairy cows predispose them to metabolic disorders. Insulin as a main metabolic hormone has a key role to maintain homeorhesis in dairy cows. Insulin resistance phenomenon can expose these animals to metabolic dysfunctions. Information regarding insulin resistance at each physiological state of high producing dairy cows can assist veterinarians to control and prevent the metabolic disorders at herd levels.Materials, Methods & Results: This research was carried out at winter 2014 on 25 multiparous Holstein dairy cows from a high producing industrial dairy farm. The total mixed rations were formulated and prepared for all animals according to National Research Council (NRC) requirements. At this farm, a dry period of 60 days has been considered. Milk production was about 10,000 kg for year, an average of 3.6 of milk fat %, and 3.3 of milk protein %. All the animals were clinically healthy and body condition score (BCS) was estimated based on 0 to 5 system. Cattle were divided into 5 equal groups containing early, mid and late lactations, far-off and close-up dry periods. A blood sample was taken immediately after catheterization, and dextrose 50% was administered at 500 mg/kg, 10 mL/kg/h, subsequently. Blood samples were collected from all cows through the fixed catheter prior to and 1, 2, 3 and 4 h after dextrose 50% infusion in plain tubes. After sera separation, glucose and insulin were detected in all samples. Significant and rapid elevation of serum glucose and insulin concentrations were seen in all studied animals at 1st h after dextrose administration (P < 0.05). Decreasing the glucose level near to base line levels was seen at h 4 in late lactation and far-off dry cows. The glucose level at this time was remained significantly higher than h zero in other groups (P < 0.05).[...]