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1.
Proc Natl Acad Sci U S A ; 119(32): e2208855119, 2022 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-35914126

RESUMO

Wild-type (WT) mice maintain viable levels of blood glucose even when adipose stores are depleted by 6 d of 60% calorie restriction followed by a 23-h fast (hereafter designated as "starved" mice). Survival depends on ghrelin, an octanoylated peptide hormone. Mice that lack ghrelin suffer lethal hypoglycemia when subjected to the same starvation regimen. Ghrelin is known to stimulate secretion of growth hormone (GH), which in turn stimulates secretion of IGF-1 (insulin-like growth factor-1). In the current study, we found that starved ghrelin-deficient mice had a 90% reduction in plasma IGF-1 when compared with starved WT mice. Injection of IGF-1 in starved ghrelin-deficient mice caused a twofold increase in glucose production and raised blood glucose to levels seen in starved WT mice. Increased glucose production was accompanied by increases in plasma glycerol, fatty acids and ketone bodies, and hepatic triglycerides. All of these increases were abolished when the mice were treated with atglistatin, an inhibitor of adipose tissue triglyceride lipase. We conclude that IGF-1 stimulates adipose tissue lipolysis in starved mice and that this lipolysis supplies energy and substrates that restore hepatic gluconeogenesis. This action of IGF-1 in starved mice is in contrast to its known action in inhibiting adipose tissue lipase in fed mice. Surprisingly, the ghrelin-dependent maintenance of plasma IGF-1 in starved mice was not mediated by GH. Direct injection of GH into starved ghrelin-deficient mice failed to increase plasma IGF-1. These data call attention to an unsuspected role of IGF-1 in the adaptation to starvation.


Assuntos
Glicemia , Fator de Crescimento Insulin-Like I , Inanição , Adaptação Fisiológica , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/enzimologia , Tecido Adiposo/metabolismo , Animais , Glicemia/metabolismo , Ácidos Graxos/sangue , Grelina/metabolismo , Gluconeogênese , Glicerol/sangue , Hormônio do Crescimento/metabolismo , Fator de Crescimento Insulin-Like I/análise , Fator de Crescimento Insulin-Like I/metabolismo , Corpos Cetônicos/sangue , Lipase/antagonistas & inibidores , Lipase/metabolismo , Lipólise , Fígado/metabolismo , Camundongos , Compostos de Fenilureia/farmacologia , Inanição/sangue , Inanição/metabolismo , Triglicerídeos/metabolismo
2.
Proc Natl Acad Sci U S A ; 116(15): 7449-7454, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30910968

RESUMO

When mice are subjected to 60% calorie restriction for several days, they lose nearly all of their body fat. Although the animals lack energy stores, their livers produce enough glucose to maintain blood glucose at viable levels even after a 23-hour fast. This adaptation is mediated by a marked increase in plasma growth hormone (GH), which is elicited by an increase in plasma ghrelin, a GH secretagogue. In the absence of ghrelin, calorie-restricted mice develop hypoglycemia, owing to diminished glucose production. To determine the site of GH action, in the current study we used CRISPR/Cas9 and Cre recombinase technology to produce mice that lack GH receptors selectively in liver (L-Ghr-/- mice) or in adipose tissue (Fat-Ghr-/- mice). When subjected to calorie restriction and then fasted for 23 hours, the L-Ghr-/- mice, but not the Fat-Ghr-/- mice, developed hypoglycemia. The fall in blood glucose in L-Ghr-/- mice was correlated with a profound drop in hepatic triglycerides. Hypoglycemia was prevented by injection of lactate or octanoate, two sources of energy to support gluconeogenesis. Electron microscopy revealed extensive autophagy in livers of calorie-restricted control mice but not in L-Ghr-/- mice. We conclude that GH acts through its receptor in the liver to activate autophagy, preserve triglycerides, enhance gluconeogenesis, and prevent hypoglycemia in calorie-restricted mice, a model of famine.


Assuntos
Autofagia , Glicemia/metabolismo , Restrição Calórica , Hormônio do Crescimento/sangue , Hipoglicemia/sangue , Fígado/metabolismo , Inanição/sangue , Animais , Glicemia/genética , Doença Crônica , Modelos Animais de Doenças , Hormônio do Crescimento/genética , Hipoglicemia/genética , Fígado/patologia , Camundongos , Camundongos Knockout , Inanição/genética , Inanição/patologia
3.
Artigo em Inglês | MEDLINE | ID: mdl-34728403

RESUMO

The study was designed to identify the types of mitogen-activated protein kinases (MAPKs) in erythrocytes and liver tissues of river lamprey Lampetra fluviatilis and monitor the changes in protein expression levels of found enzymes on the course of prespawning starvation (from November to the end of May). Immunoreactivity of the native and phosphorylated forms of ERK1/2, JNK and p38 was examined in the cytosolic and membrane cell fractions. Both lamprey erythrocytes and liver were found to highly express ERK1/2 and JNK, whereas only trace amounts of p38 were revealed in hepatic tissues. ERK1/2 was identified in cytosolic and membrane fractions, whereas JNK and p38 were predominantly cytosolic enzymes. Total cellular amounts of ERK1/2 and phospho-ERK1/2 in both erythrocytes and liver tissues appeared to be relatively stable on the course of prespawning starvation. However, before spawning ERK1/2 translocated from cytosol to membranes, with partial decline of its cytoplasmic expression being compensated by increases in membrane-bound pool. Immunoreactivity of cytoplasmic JNK, phospho-JNK and p38 were stable from November to March, but sharply decreased before spawning exhibiting almost negligible levels in May, which suggests the depletion of their cellular fractions. Most probably, ERK1/2 plays more important role in mediating adaptive responses of erythrocytes and liver tissues to conditions of natural starvation and maintenance of cell viability before spawning and death of animals in May.


Assuntos
Proteínas de Peixes/metabolismo , Lampreias/metabolismo , Fígado/enzimologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Animais , Eritrócitos/enzimologia , Feminino , Proteínas de Peixes/sangue , Lampreias/sangue , Masculino , Proteínas Quinases Ativadas por Mitógeno/sangue , Reprodução , Estações do Ano , Inanição/sangue , Inanição/enzimologia , Frações Subcelulares/enzimologia
4.
Gastroenterology ; 146(4): 1060-9, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24361124

RESUMO

BACKGROUND & AIMS: Hepatic gluconeogenesis provides fuel during starvation, and is abnormally induced in obese individuals or those with diabetes. Common metabolic disorders associated with active gluconeogenesis and insulin resistance (obesity, metabolic syndrome, diabetes, and nonalcoholic fatty liver disease) have been associated with alterations in iron homeostasis that disrupt insulin sensitivity and promote disease progression. We investigated whether gluconeogenic signals directly control Hepcidin, an important regulator of iron homeostasis, in starving mice (a model of persistently activated gluconeogenesis and insulin resistance). METHODS: We investigated hepatic regulation of Hepcidin expression in C57BL/6Crl, 129S2/SvPas, BALB/c, and Creb3l3-/- null mice. Mice were fed a standard, iron-balanced chow diet or an iron-deficient diet for 9 days before death, or for 7 days before a 24- to 48-hour starvation period; liver and spleen tissues then were collected and analyzed by quantitative reverse-transcription polymerase chain reaction and immunoblot analyses. Serum levels of iron, hemoglobin, Hepcidin, and glucose also were measured. We analyzed human hepatoma (HepG2) cells and mouse primary hepatocytes to study transcriptional control of Hamp (the gene that encodes Hepcidin) in response to gluconeogenic stimuli using small interfering RNA, luciferase promoter, and chromatin immunoprecipitation analyses. RESULTS: Starvation led to increased transcription of the gene that encodes phosphoenolpyruvate carboxykinase 1 (a protein involved in gluconeogenesis) in livers of mice, increased levels of Hepcidin, and degradation of Ferroportin, compared with nonstarved mice. These changes resulted in hypoferremia and iron retention in liver tissue. Livers of starved mice also had increased levels of Ppargc1a mRNA and Creb3l3 mRNA, which encode a transcriptional co-activator involved in energy metabolism and a liver-specific transcription factor, respectively. Glucagon and a cyclic adenosine monophosphate analog increased promoter activity and transcription of Hamp in cultured liver cells; levels of Hamp were reduced after administration of small interfering RNAs against Ppargc1a and Creb3l3. PPARGC1A and CREB3L3 bound the Hamp promoter to activate its transcription in response to a cyclic adenosine monophosphate analog. Creb3l3-/- mice did not up-regulate Hamp or become hypoferremic during starvation. CONCLUSIONS: We identified a link between glucose and iron homeostasis, showing that Hepcidin is a gluconeogenic sensor in mice during starvation. This response is involved in hepatic metabolic adaptation to increased energy demands; it preserves tissue iron for vital activities during food withdrawal, but can cause excessive iron retention and hypoferremia in disorders with persistently activated gluconeogenesis and insulin resistance.


Assuntos
Gluconeogênese , Hepatócitos/metabolismo , Hepcidinas/sangue , Ferro/sangue , Fígado/metabolismo , Transdução de Sinais , Inanição/sangue , Animais , Sítios de Ligação , Glicemia/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/deficiência , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Modelos Animais de Doenças , Hemoglobinas/metabolismo , Células Hep G2 , Homeostase , Humanos , Resistência à Insulina , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Regiões Promotoras Genéticas , Interferência de RNA , Baço/metabolismo , Inanição/genética , Fatores de Tempo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica , Transfecção , Regulação para Cima
5.
Nutr J ; 14: 41, 2015 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-25897953

RESUMO

BACKGROUND: Ketogenic diets are high fat and low carbohydrate or very low carbohydrate diets, which render high production of ketones upon consumption known as nutritional ketosis (NK). Ketosis is also produced during fasting periods, which is known as fasting ketosis (FK). Recently, the combinations of NK and FK, as well as NK alone, have been used as resources for weight loss management and treatment of epilepsy. METHODS: A crossover study design was applied to 11 healthy individuals, who maintained moderately sedentary lifestyle, and consumed three types of diet randomly assigned over a three-week period. All participants completed the diets in a randomized and counterbalanced fashion. Each weekly diet protocol included three phases: Phase 1 - A mixed diet with ratio of fat: (carbohydrate + protein) by mass of 0.18 or the equivalence of 29% energy from fat from Day 1 to Day 5. Phase 2- A mixed or a high-fat diet with ratio of fat: (carbohydrate + protein) by mass of approximately 0.18, 1.63, or 3.80 on Day 6 or the equivalence of 29%, 79%, or 90% energy from fat, respectively. Phase 3 - A fasting diet with no calorie intake on Day 7. Caloric intake from diets on Day 1 to Day 6 was equal to each individual's energy expenditure. On Day 7, ketone buildup from FK was measured. RESULTS: A statistically significant effect of Phase 2 (Day 6) diet was found on FK of Day 7, as indicated by repeated analysis of variance (ANOVA), F(2,20) = 6.73, p < 0.0058. Using a Fisher LDS pair-wise comparison, higher significant levels of acetone buildup were found for diets with 79% fat content and 90% fat content vs. 29% fat content (with p = 0.00159**, and 0.04435**, respectively), with no significant difference between diets with 79% fat content and 90% fat content. In addition, independent of the diet, a significantly higher ketone buildup capability of subjects with higher resting energy expenditure (R(2) = 0.92), and lower body mass index (R(2) = 0.71) was observed during FK.


Assuntos
Acetona/sangue , Acetona/urina , Biomarcadores/sangue , Gorduras na Dieta/administração & dosagem , Cetose/sangue , Inanição/sangue , Adulto , Glicemia/metabolismo , Testes Respiratórios , Estudos Cross-Over , Dieta com Restrição de Carboidratos , Dieta Cetogênica , Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Ingestão de Energia , Metabolismo Energético , Jejum , Feminino , Voluntários Saudáveis , Humanos , Cetose/diagnóstico , Masculino , Comportamento Sedentário , Inquéritos e Questionários , Redução de Peso , Adulto Jovem
6.
Curr Diab Rep ; 14(10): 536, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25173690

RESUMO

Overnutrition is a major cause of diabetes. The contrary situation of undernutrition has also been suggested to increase the risk of the disease. Especially undernutrition during prenatal life has been hypothesized to program the structure and physiology of the fetus in such a way that it is more prone to develop diabetes in later life. Famines over the last 100 years have provided historical opportunities to study later-life health consequences of poor nutritional circumstances in early life. The majority of studies based on famine exposure during prenatal life clearly show that diabetes risk is increased. Postnatal famine exposure in childhood, adolescence, or young adulthood also seems to raise risk for diabetes, although prenatal famine effects seem to be more substantial. These study results not only have implications for the consequences of famines still happening but also for pregnancies complicated by factors mimicking poor nutritional situations.


Assuntos
Complicações na Gravidez/epidemiologia , Efeitos Tardios da Exposição Pré-Natal/epidemiologia , Inanição/epidemiologia , Sobreviventes/estatística & dados numéricos , Adolescente , Criança , Pré-Escolar , Feminino , Desenvolvimento Fetal , Humanos , Lactente , Fenômenos Fisiológicos da Nutrição do Lactente , Recém-Nascido , Fenômenos Fisiológicos da Nutrição Materna , Insuficiência Placentária/epidemiologia , Insuficiência Placentária/etiologia , Insuficiência Placentária/fisiopatologia , Gravidez , Complicações na Gravidez/sangue , Complicações na Gravidez/etiologia , Complicações na Gravidez/fisiopatologia , Efeitos Tardios da Exposição Pré-Natal/sangue , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Medição de Risco , Inanição/sangue , Inanição/complicações , Inanição/fisiopatologia
7.
Anal Bioanal Chem ; 405(25): 8083-91, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23732868

RESUMO

D-Alanine (D-Ala) is one of the naturally occurring D-amino acids in mammals, and its amount is known to have characteristic circadian changes. It is a candidate for a novel physiologically active substance and/or a biomarker, and the regulation mechanisms of the intrinsic amounts of D-Ala are expected to be clarified. In the present study, the effects of the possible factors controlling the D-Ala amounts, e.g., diet, D-amino acid oxidase (DAO) and intestinal bacteria, on the day-night changes in the intrinsic D-Ala amounts have been investigated using a highly sensitive and selective two-dimensional high-performance liquid chromatographic system combining a reversed-phase column and an enantioselective column. The circadian rhythm was not changed under fasting conditions. In the mice lacking D-amino acid oxidase activity (ddY/DAO(-) mice), clear day-night changes were still observed, suggesting that the factors controlling the D-Ala rhythm were not their food and DAO activity. On the other hand, in the germ-free mice, quite low amounts of D-Ala were detected compared with those in the control mice, indicating that the main origin of D-Ala in the mice is intestinal bacteria. Because the D-Ala amounts in the digesta containing intestinal bacteria did not show the day-night changes, the controlling factor of the circadian changes of the D-Ala amount was suggested to be the intestinal absorption.


Assuntos
Alanina/sangue , Alanina/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Animais , Ritmo Circadiano , D-Aminoácido Oxidase/metabolismo , Intestinos/microbiologia , Isomerismo , Masculino , Camundongos , Ratos Sprague-Dawley , Ratos Wistar , Inanição/sangue , Inanição/metabolismo
8.
Int J Eat Disord ; 46(4): 369-74, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23280717

RESUMO

OBJECTIVE: The purpose of this article is to clarify the finding of liver function test abnormalities in anorexia nervosa (AN). METHOD: Literature review and description of two representative cases of severe liver function test abnormalities from our medical stabilization unit. RESULTS: Abnormal elevation of liver function tests can occur during the process of refeeding patients with severe AN. The cause of this elevation is either due to excessive glucose deposition in liver cells or represents liver cell death due to the sequelae of prolonged starvation which characterizes AN before refeeding is adequately in process.


Assuntos
Anorexia Nervosa/fisiopatologia , Fígado/fisiopatologia , Inanição/fisiopatologia , Adulto , Alanina Transaminase/sangue , Anorexia Nervosa/sangue , Aspartato Aminotransferases/sangue , Feminino , Humanos , Testes de Função Hepática , Inanição/sangue
9.
J Am Anim Hosp Assoc ; 49(2): 101-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23325600

RESUMO

The objectives of this retrospective study were to identify the most common clinicopathologic abnormalities in starved dogs, assess the time required for those abnormalities to resolve, and determine whether clinicopathologic abnormalities recorded at time of intake to the hospital influenced time to regain weight. Records of 152 very underweight or emaciated dogs seized by the American Society for the Prevention of Cruelty to Animals (ASPCA) Humane Law Enforcement (HLE) division were reviewed. Dogs were classified as emaciated if the admission body weight was estimated to be ≥ 30% below the anticipated ideal body weight and classified as very underweight if the admission weight was estimated to be 20-29% below the anticipated ideal body weight. An initial minimum database was obtained on each animal, and when possible, clinicopathologic abnormalities were serially assessed. The most common initial abnormalities, present in ≥ 25% of dogs, were hypoalbuminemia, thrombocytosis, anemia, elevated blood urea nitrogen (BUN), elevated BUN/creatinine ratio, and hypocalcemia. Mean time to gain 20% of admission body weight was similar for the abnormalities studied. Although there was some evidence that dogs with anemia and/or hypoalbuminemia required more days to gain weight, future studies are required for confirmation.


Assuntos
Peso Corporal/fisiologia , Doenças do Cão/fisiopatologia , Inanição/veterinária , Aumento de Peso , Animais , Proteínas Sanguíneas/análise , Nitrogênio da Ureia Sanguínea , Creatinina/análise , Doenças do Cão/sangue , Cães , Feminino , Hipoalbuminemia/epidemiologia , Hipoalbuminemia/etiologia , Hipoalbuminemia/terapia , Hipoalbuminemia/veterinária , Masculino , Estudos Retrospectivos , Inanição/sangue , Inanição/fisiopatologia , Trombocitose/epidemiologia , Trombocitose/etiologia , Trombocitose/terapia , Trombocitose/veterinária , Fatores de Tempo
10.
Zh Evol Biokhim Fiziol ; 49(2): 144-52, 2013.
Artigo em Russo | MEDLINE | ID: mdl-23789400

RESUMO

Activity of Na,K-ATPase (Na+,K+-adenosine triphosphatase, EC 3.6.3.9) in the whole erythrocytes was studied in dynamics of the complete rat alimentary starvation for 1, 3, 5, 7-8, and 10-12 days with water drinking ad libitum. There has been established a change of the erythrocyte Na,K-ATPase activity depending on the phase of starvation (the period connected with a certain level of metabolism). After the state on an empty stomach and adaptation to endogenous nutrition (the 0-I phase), from the 3rd to the 7-8th starvation day, the II phase, the period of compensated adaptation occurs (the euglycemia is preserved, the plateau level is preserved, the plateau level is achieved for protein loss and hormonal stimulation). Changes of the Na,K-ATPase activity level within the limits of the II phase were insignificant (p < 0.05), but loses of potassium content in plasma and erythrocytes have been from the 5th starvation day. The III phase (the 12-13th day) is the beginning of the terminal period and is characterized by a decrease of the Na,K-ATPase activity (the oubain-sensitive activity) and of Mg2+-ATPase (the oubain-independent activity), by a decrease of the plasma sodium level (prior to that, this level remained practically unchanged). Ad causes of the revealed decrease of the ATPase activities at the long-term starvation, there are considered aging of population of circulating erythrocytes (the absence of reticulocytes and young erythrocytes), depletion of cell energetic resources (hypoglycemia and glycopenia), effect of endogenous oubain, and endotoxemia.


Assuntos
Adaptação Fisiológica , Eritrócitos/enzimologia , Privação de Alimentos/fisiologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Inanição/sangue , Animais , Masculino , Potássio/sangue , Ratos , Sódio/sangue , Inanição/enzimologia , Inanição/fisiopatologia , Fatores de Tempo
11.
Am J Physiol Gastrointest Liver Physiol ; 302(3): G365-74, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22114114

RESUMO

In starvation, glycerol is released from adipose tissue and serves as an important precursor for hepatic gluconeogenesis. By unknown sex-specific mechanisms, women suppress the endogenous glucose production better than men and respond to metabolic stress with higher plasma glycerol levels. Hepatic glycerol uptake is facilitated by aquaporin-9 (AQP9), a broad-selectivity neutral solute channel, and represents an insulin-regulated step in supplying gluconeogenesis with glycerol. In the present study, hepatic AQP9 abundance was increased 2.6-fold in starved male rats as assessed by immunoblotting and immunohistochemistry. By contrast, starvation had no significant effect on hepatic AQP9 expression in female rats. Coordinately, plasma glycerol levels remained unchanged with starvation in male rats, whereas it was increased in female rats. The different responses to starvation were paralleled by higher glycerol permeability in basolateral hepatocyte membranes from starved male rats compared with starved females. Ovariectomy led to a starvation-response pattern identical to that observed in male rats with increased hepatic AQP9 expression and unchanged plasma glycerol levels. In cultured hepatocytes, 17ß-estradiol and the selective estrogen receptor α-agonist, propyl pyrazole triol, caused a decrease in AQP9 expression. Our results support that a sex-specific regulation of the hepatic glycerol channel AQP9 during starvation contributes to the higher plasma glycerol levels observed in women during fasting and possibly results in a lower cytosolic availability of glycerol. Furthermore, the sexual dimorphism in the hepatic handling of glycerol during starvation might be explained by 17ß-estradiol preventing the starvation-induced increase in hepatic AQP9 abundance.


Assuntos
Aquaporinas/metabolismo , Estrogênios/farmacologia , Glicerol/metabolismo , Fígado/metabolismo , Inanição/metabolismo , Animais , Aquaporinas/antagonistas & inibidores , Aquaporinas/genética , Glicemia/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Diabetes Mellitus Experimental/metabolismo , Estradiol/farmacologia , Ácidos Graxos não Esterificados/sangue , Feminino , Expressão Gênica/genética , Glicerol/sangue , Glicerol Quinase/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Células Híbridas/efeitos dos fármacos , Células Híbridas/metabolismo , Insulina/sangue , Insulina/farmacologia , Masculino , Cloreto de Mercúrio/farmacologia , Orquiectomia , Ovariectomia , Permeabilidade/efeitos dos fármacos , Fenóis , Floretina/farmacologia , Período Pós-Prandial/fisiologia , Pirazóis/farmacologia , Ratos , Ratos Wistar , Caracteres Sexuais , Inanição/sangue , Água/metabolismo
12.
Br J Nutr ; 107(1): 52-60, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21733331

RESUMO

Prolonged starvation changes energy metabolism; therefore, the metabolic response to starvation is divided into three phases according to changes in glucose, lipid and protein utilisation. B-group vitamins are involved in energy metabolism via metabolism of carbohydrates, fatty acids and amino acids. To determine how changes in energy metabolism alter B-group vitamin concentrations during starvation, we measured the concentration of eight kinds of B-group vitamins daily in rat blood, urine and in nine tissues including cerebrum, heart, lung, stomach, kidney, liver, spleen, testis and skeletal muscle during 8 d of starvation. Vitamin B1, vitamin B6, pantothenic acid, folate and biotin concentrations in the blood reduced after 6 or 8 d of starvation, and other vitamins did not change. Urinary excretion was decreased during starvation for all B-group vitamins except pantothenic acid and biotin. Less variation in B-group vitamin concentrations was found in the cerebrum and spleen. Concentrations of vitamin B1, vitamin B6, nicotinamide and pantothenic acid increased in the liver. The skeletal muscle and stomach showed reduced concentrations of five vitamins including vitamin B1, vitamin B2, vitamin B6, pantothenic acid and folate. Concentrations of two or three vitamins decreased in the kidney, testis and heart, and these changes showed different patterns in each tissue and for each vitamin. The concentration of pantothenic acid rapidly decreased in the heart, stomach, kidney and testis, whereas concentrations of nicotinamide were stable in all tissues except the liver. Different variations in B-group vitamin concentrations in the tissues of starved rats were found. The present findings will lead to a suitable supplementation of vitamins for the prevention of the re-feeding syndrome.


Assuntos
Inanição/metabolismo , Complexo Vitamínico B/metabolismo , Animais , Metabolismo Energético , Masculino , Estado Nutricional , Tamanho do Órgão , Especificidade de Órgãos , Distribuição Aleatória , Ratos , Ratos Wistar , Inanição/sangue , Inanição/patologia , Inanição/urina , Fatores de Tempo , Complexo Vitamínico B/sangue , Complexo Vitamínico B/urina , Redução de Peso
13.
Proc Natl Acad Sci U S A ; 106(26): 10853-8, 2009 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-19541642

RESUMO

The liver plays a crucial role in mobilizing energy during nutritional deprivation. During the early stages of fasting, hepatic glycogenolysis is a primary energy source. As fasting progresses and glycogen stores are depleted, hepatic gluconeogenesis and ketogenesis become major energy sources. Here, we show that fibroblast growth factor 21 (FGF21), a hormone that is induced in liver by fasting, induces hepatic expression of peroxisome proliferator-activated receptor gamma coactivator protein-1alpha (PGC-1alpha), a key transcriptional regulator of energy homeostasis, and causes corresponding increases in fatty acid oxidation, tricarboxylic acid cycle flux, and gluconeogenesis without increasing glycogenolysis. Mice lacking FGF21 fail to fully induce PGC-1alpha expression in response to a prolonged fast and have impaired gluconeogenesis and ketogenesis. These results reveal an unexpected relationship between FGF21 and PGC-1alpha and demonstrate an important role for FGF21 in coordinately regulating carbohydrate and fatty acid metabolism during the progression from fasting to starvation.


Assuntos
Adaptação Fisiológica/fisiologia , Metabolismo dos Carboidratos , Ácidos Graxos/metabolismo , Fatores de Crescimento de Fibroblastos/fisiologia , Inanição/fisiopatologia , Transativadores/metabolismo , Adaptação Fisiológica/genética , Animais , Glicemia/metabolismo , Western Blotting , Peso Corporal/genética , Peso Corporal/fisiologia , Jejum/sangue , Jejum/fisiologia , Feminino , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Gluconeogênese/genética , Insulina/sangue , Metabolismo dos Lipídeos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Oxirredução , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Inanição/sangue , Transativadores/genética , Fatores de Transcrição , Triglicerídeos/sangue
14.
Fish Physiol Biochem ; 38(4): 1145-1157, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22228074

RESUMO

The particular metabolic strategies of the common dentex (Dentex dentex) to face a period of prolonged starvation and subsequent refeeding were assessed. Plasma metabolites, endogenous reserves, and the activity of key enzymes of intermediary metabolism in liver, white muscle, and heart were evaluated. Plasma glucose, total lipid, triglycerides, total-, HDL- and LDL-cholesterol, and protein levels, liver, and white muscle glycogen, and perivisceral, and muscle fat were significantly reduced by starvation, whereas liver lipid content was surprisingly increased. Those enzymes involved in phosphorylation and oxidation of glucose and lipid synthesis, as well as alanine aminotransferase activity, were significantly depressed in liver of starved fish. The increase in ß-hydroxyacyl-CoA dehydrogenase (HOAD) indicated an enhanced fatty acid oxidation during starvation. Part of the acetyl-CoA generated by ß-oxidation was oxidized in the hepatic Krebs cycle, as reflected the increased citrate synthase (CS) activity. The oxaloacetate required for the reaction catalized by CS activity would be supplied by aspartate aminotransferase (ASAT) activity whose activity was also enhanced. Glutamate dehydrogenase also increased to deaminate the glutamate produced by transaminases, especially by the increased ASAT activity. Liver gluconeogenesis of starved fish was maintained at the same rate that in controls, with glycerol playing an important role as glucogenic substrate. The increased hepatic ß-hydroxybutyrate dehydrogenase (ß-OHBDH) activity indicates that part of the acetyl-CoA arriving from ß-oxidation was being diverted for ketone bodies production with dentex liver playing an important role in providing ketone bodies as fuels for other tissues under such circumstances. Most enzyme activities in white muscle of starved dentex were significantly depressed. In heart, starvation induced an important inhibition of those enzymes involved in glucose and protein metabolism, whereas CS, HOAD, and ß-OHBDH activities were maintained at control levels. Although several biomarkers assayed returned to control values after refeeding, many others did not, which indicate that after 3 weeks of refeeding, pre-starved dentex is still experiencing a transient period of metabolic adjustments directed toward the restoration of body mass.


Assuntos
Perciformes/sangue , Inanição/sangue , Animais , Gordura Intra-Abdominal/metabolismo , Fígado/metabolismo , Fibras Musculares de Contração Rápida/metabolismo , Miocárdio/metabolismo , Perciformes/metabolismo , Inanição/metabolismo
15.
Zh Evol Biokhim Fiziol ; 48(6): 548-56, 2012.
Artigo em Russo | MEDLINE | ID: mdl-23401964

RESUMO

Comparative study has been carried of effect of the three-day long starvation, running, and their combination on morphological parameters of rat blood, lipid metabolism, and activity of blood Na,K-ATPase. Different effect has been shown of these stress factors on the blood erythrocyte composition. Starvation is accompanied by the most pronounced release of stored erythrocyte into blood, which results in a significant decrease both of the total amount of reticulocytes and the complete absence of reticulocytes of the I stage of maturity (the youngest). The running on treadmill led to a significant increase of the total amount of blood reticulocytes and to multiple increase of immature reticulocytes (RC-I and RC-II), which can indicate some stress of the bone marrow erythroid stem line. The curve of acid resistance of blood reticulocytes has shown the animal to experience the greatest stress at a combination of starvation and running. Starvation and running produced different effects on blood lipid characteristics. The content of triacylglycerides (TAG) in blood rose by 40% at starvation and decreased by 30% at running, a similar tendency being found for index of atherogeneity. The fatty acid composition of blood phospholipids at running and its combination with starvation practically did not differ from control. A change of Na,K-ATPase, which is so characteristic of reaction to various kinds of stress, sharply fell at starvation (by 22%), but increased at running (by 13%) and decreased markedly at combination of these actions. Absorption spectra of lipid extracts of the whole blood of the rats submitted to various stress actions showed that extracted from blood (at different amount depending on the kind of action) is an organic substance with coupled bonds, which absorbs light in the diapason of 360-620 nm. The absorption of light in the diapason of 400-410 nm has been found to belong to the Soret band of ferroheme and ferriheme. The shift of the Soret band indicates electron transitions in the iron cation. By the change and disappearance of the Soret band, it is possible to judge about the processes occurring in the lipid extract. The disappearance of the Soret band in the lipid extract indicates formation in it of steady radicals as a result of the ferriheme disintegration due to accumulation of energy in porphyrin, which does not seem to occur in the blood cell membranes. The iron atom in the ferriheme molecule is known to accept electron and yields a part of energy probably to porphyrin. Then ferriheme yields electron and becomes ferriheme with excess of energy in porphyrin. Hence, at admission of the next electron to the iron atom the porphyrin molecule is to get rid of the energy obtained earlier to prevent its disintegration. The heme is possible to be an accumulator and distributor of energy in tissue.


Assuntos
Heme , Ferro , Lipídeos/sangue , Reticulócitos , Animais , Ácidos Graxos/sangue , Heme/análise , Heme/metabolismo , Hemina/metabolismo , Ferro/análise , Ferro/metabolismo , Luz , Masculino , Fosfolipídeos/sangue , Condicionamento Físico Animal , Porfirinas/sangue , Ratos , Contagem de Reticulócitos , Reticulócitos/citologia , Reticulócitos/metabolismo , ATPase Trocadora de Sódio-Potássio/sangue , Inanição/sangue , Inanição/metabolismo
16.
Nutrients ; 13(9)2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34578904

RESUMO

The liver function is essential for metabolism, detoxification, and bile synthesis, even in the neonatal period. Autophagy plays significance roles in THE adult liver, whereas the role of liver autophagy in the early neonatal period largely remains unclear. To clarify the importance of liver autophagy in the neonatal starvation period, we generated liver-specific autophagy-deficient (Atg5flox/flox; Albumin-Cre) mice and investigated under starvation conditions comparing with control (Atg5flox/+; Albumin-Cre) mice, focusing on serum metabolites and liver histopathology. As a result, autophagy in the liver was found to unessential for the survival under postnatal starvation. A metabolomics analysis of serum metabolites by gas chromatography-tandem mass spectrometry showed a significant difference between the groups, especially after 12-h starvation, suggesting the synergistical adaption of metabolic pathways, such as the "malate-aspartate shuttle", "aspartate metabolism", "urea cycle", and "glycine and serine metabolism". Liver-specific autophagy-deficiency under postnatal starvation conditions can cause a characteristic metabolic alteration suggesting a change of the mitochondrial function. Neonates seemed to maintain ketone production under starvation conditions, even in the autophagy-deficient liver, through a change in the mitochondrial function, which may be an adaptive mechanism for avoiding fatal starvation.


Assuntos
Proteína 5 Relacionada à Autofagia/deficiência , Autofagia , Fígado/metabolismo , Metaboloma , Inanição/sangue , Animais , Animais Recém-Nascidos , Cromatografia Gasosa-Espectrometria de Massas , Camundongos
17.
Pediatr Res ; 67(2): 138-43, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19809375

RESUMO

Glucose is a major fuel for fetal development. Fetal blood glucose level is mainly dependent on maternal blood glucose concentration, though it is also regulated by fetal insulin level. Thioredoxin binding protein-2 (TBP-2), which is identical to vitamin D3 up-regulated protein (VDUP1) and thioredoxin interacting protein (Txnip), was recently reported to be a key transcriptional factor controlling glucose metabolism. Here, we elucidated the functions of TBP-2 in maintaining blood glucose homeostasis during the fetal period. TBP-2(+/-) female mice were mated with TBP-2(+/-) male mice; beginning 16.5-d post coitum, pregnant mice were fed or fasted for 24 h. Under conditions of maternal starvation, the blood glucose levels of TBP-2(-/-) fetuses were significantly lower than those of TBP-2(+/+) fetuses, corresponding to the elevated plasma insulin levels of TBP-2(-/-) fetuses compared with those of TBP-2(+/+) fetuses. There was no difference between TBP-2(+/+) and TBP-2(-/-) fetuses in terms of their pancreatic beta-cell masses or the expression of placental glucose transporters under conditions of either maternal feeding or fasting. Thus, during maternal fasting, fetal TBP-2 suppresses excessive insulin secretion to maintain the fetus's glucose levels, implying that TBP-2 is a critical molecule in mediating fetal glucose homeostasis depending on nutrient availability.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Glicemia/metabolismo , Proteínas de Transporte/metabolismo , Transtornos da Nutrição Fetal/prevenção & controle , Hipoglicemia/prevenção & controle , Insulina/sangue , Fenômenos Fisiológicos da Nutrição Pré-Natal , Inanição/complicações , Tiorredoxinas/metabolismo , Animais , Proteínas de Transporte/genética , Modelos Animais de Doenças , Regulação para Baixo , Feminino , Sangue Fetal/metabolismo , Transtornos da Nutrição Fetal/sangue , Transtornos da Nutrição Fetal/genética , Peso Fetal , Regulação da Expressão Gênica , Idade Gestacional , Gluconeogênese/genética , Homeostase , Hipoglicemia/sangue , Hipoglicemia/embriologia , Hipoglicemia/genética , Células Secretoras de Insulina/metabolismo , Ácido Láctico/sangue , Fígado/embriologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Knockout , Pâncreas/embriologia , Pâncreas/metabolismo , Placenta/patologia , Gravidez , Inanição/sangue , Inanição/genética , Tiorredoxinas/genética
18.
Fish Physiol Biochem ; 36(1): 71-83, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19093221

RESUMO

The physiological effects of short-term starvation on some haematological, biochemical and non-specific immune response parameters together with the histological structure of the skin, were investigated in the European eel, Anguilla anguilla. Blood haemoglobin and haematocrit, serum glucose and cortisol, hemolysins, haemagglutinins, and lysozyme in the plasma, kidney and epidermal extract, were measured in fish after 31, 42 and 58 days of starvation, and compared to those of fed fish. Starvation did not affect haemoglobin and haematocrit values, while an increase in glucose and cortisol levels was found in starved eels by day 42. Haemolytic and haemagglutinating activities decreased in starved eels. On the other hand, starvation caused an increase in the lysozyme content in the epidermal extracts, while no significant variations were observed in kidney and plasma. On the whole, no major changes in metabolic, haematological and non-specific immune parameters were observed when short-term (less than 2 months) starvation was applied to the European eel, suggesting an adaptive response to starvation, rather than a typical alarm-stress response, allowing this species to withstand food deprivation.


Assuntos
Anguilla/fisiologia , Fenômenos Fisiológicos da Pele , Inanição/veterinária , Adaptação Fisiológica/fisiologia , Anguilla/sangue , Anguilla/imunologia , Animais , Análise Química do Sangue , Tamanho Corporal , Pele/citologia , Fenômenos Fisiológicos da Pele/imunologia , Inanição/sangue , Inanição/imunologia , Fatores de Tempo
19.
Patol Fiziol Eksp Ter ; (3): 38-40, 2010.
Artigo em Russo | MEDLINE | ID: mdl-20853619

RESUMO

The results obtained on the model of starvation shows that nutritional dropsy led to the significant decrease of glucose, total cholesterol (TCh) and triglycerides (TC), as well as increase of non-estherified fatty acids (NEFA) in blood serum. In the rats with nutritional dropsy after treatment fed with standard diet enriched with soybean protein body weight returned to normal values as well as levels of Glucose, TCh and TC. However, concentration of NEFA remained increased. In the experimental group received additionally taurepar or taurhythman the level of NEFA decreased up to the normal one. It is necessary to mention that taurine derivatives did not change the biochemical parameters in blood of normal non-starved rats. We suppose that these new substances promote reduction of intensity of hyperlipidemic processes. It is known, that during starvation incomplete oxidation of fatty acids leads to acidosis with following destruction of mitochondria membraine. Finding property of taurine derivatives to decrease the concentration of non-estherified fatty acids points at their ability for restoration of tricarboxilic acid's cycle and prevention of accumulation of suboxidized molecules of NEFA and acidosis development.


Assuntos
Glicemia/metabolismo , Metabolismo dos Carboidratos/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Inanição/sangue , Taurina/análogos & derivados , Animais , Modelos Animais de Doenças , Privação de Alimentos , Masculino , Ratos , Taurina/farmacologia
20.
Ann Biol Clin (Paris) ; 78(3): 323-328, 2020 06 01.
Artigo em Francês | MEDLINE | ID: mdl-32540819

RESUMO

Ketosis is a metabolic situation involving an increase in blood and urine concentrations of ketones that, when prolonged, leads to acidosis. Moderate ketosis usually appears after a fast of a few hours, but its prolongation exposes to hyperketosis. Observation: A 25-year-old woman presented to the emergency department for cohercitive vomiting. She was fasting for a long time in a spiritual setting and had a restricted diet limited to water and vitamin supplements. Clinical and biological assessment was in favour of fasting ketoacidosis. Evolution was favorable with intravenous hydration, poly-ionic and micronutrient supplementation and a gradual resumption of oral feeding. Conclusion: We report the case of a patient with fasting ketoacidosis. Besides consequences of this ketoacidosis, the challenge was also in resuming oral feeding in order to avoid a potentially fatal inappropriate renutrition syndrome.


Assuntos
Jejum/efeitos adversos , Cetose/etiologia , Inanição/complicações , Acidose/sangue , Acidose/diagnóstico , Acidose/etiologia , Acidose/terapia , Adulto , Jejum/sangue , Feminino , Hidratação , Humanos , Cetose/sangue , Cetose/diagnóstico , Cetose/terapia , Nutrição Parenteral , Inanição/sangue , Inanição/terapia , Fatores de Tempo
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