Intestinal lymph as a readout of meal-induced GLP-1 release in an unrestrained rat model.

Intestinal lymph supposedly provides a readout for the secretion of intestinal peptides. We here assessed how mesenteric lymph duct (MLD) lymph levels of glucagon-like peptide (GLP-1), insulin, and metabolites [glucose and triglycerides (TG)] evolve after isocaloric high- and low-fat diet (HFD and LFD) meals and how they compare with hepatic portal vein (HPV) plasma levels. Moreover, we examined the effects of intraperitoneally administered GLP-1 (1 or 10 nmol/kg) on these parameters. At 20 min after the HFD meal onset, GLP-1 levels were higher in MLD lymph than in HPV plasma. No such difference occurred with the LFD meal. Intraperitoneal injections of 10 nmol/kg GLP-1 before meals enhanced the meal-induced increases in MLD lymph and HPV plasma GLP-1 levels except for the MLD lymph levels after the HFD meal. Intraperitoneal injection of 1 nmol/kg GLP-1 only increased HPV plasma GLP-1 levels at 60 min after the HFD meal. GLP-1 injections did not increase the MLD lymph or HPV plasma GLP-1 concentrations beyond the physiological range, suggesting that intraperitoneal GLP-1 injections can recapitulate the short-term effects of endogenous GLP-1. Dipeptidyl peptidase IV (DPP-IV) activity in MLD lymph was lower than in HPV plasma, which presumably contributed to the higher levels of GLP-1 in lymph than in plasma. Insulin and glucose showed similar profiles in MLD lymph and HPV plasma, whereas TG levels were higher in lymph than in plasma. These results indicate that intestinal lymph provides a sensitive readout of intestinal peptide release and potential action, in particular when fat-rich diets are consumed.

Dissociação da resposta anti-hipertensiva e metabólica à losartana e espironolactona em ratos com síndrome metabólica experimental / Dissociation of antihypertensive and metabolic response to losartan and spironolactone in experimental rats with metabolic sindrome

INTRODUÇÃO: O tratamento da hipertensão arterial (HA) em indivíduos com síndrome metabólica (SM) é um desafio, uma vez que terapias não medicamentosas são de difícil implementação e o tratamento farmacológico ideal não está totalmente estabelecido. OBJETIVO: Avaliar o bloqueio do sistema renina angiotensina aldosterona (SRAA) na pressão arterial (PA), na função e na morfologia renais em modelo experimental de SM induzida por dieta hiperlipídica. MÉTODOS: Ratos Wistar receberam ração hiperlipídica a partir da quarta semana de vida, por 20 semanas. Os grupos tratados receberam Losartana ou Espironolactona a partir da oitava semana de vida. Avaliou-se semanalmente o peso corporal e a PA de cauda por pletismografia. Ao final do experimento, foram realizados testes de tolerância oral à glicose, perfil lipídico, clearance de creatinina, medida direta da PA, análise morfométrica renal. RESULTADOS: A administração de dieta hiperlipídica se associou ao desenvolvimento de SM, caracterizada por acúmulo central de gordura, hipertensão arterial, hiperglicemia e hipertrigliceridemia. Nesse modelo não foram observadas alterações da histomorfometria renal. O bloqueio do receptor AT1 da angiotensina II (Ang II) preveniu o desenvolvimento da HA. O bloqueio mineralocorticoide não apresentou eficácia anti-hipertensiva, porém, associou-se à redução da gordura abdominal. CONCLUSÃO: A dissociação da resposta anti-hipertensiva aos bloqueios dos receptores da Ang II e mineralocorticoide indica a participação da Ang II na gênese da HA associada à obesidade. A redução da obesidade central com a Espironolactona sugere a presença de efeito adipogênico mineralocorticoide.

INTRODUCTION: The treatment of arterial hypertension (AH) in patients with metabolic syndrome (MS) is a challenge, since non drug therapies are difficult to implement and optimal pharmacological treatment is not fully established. OBJECTIVE: To assess the blockade of the rennin angiotensin aldosterone system (RAAS) in blood pressure (BP) in renal function and morphology in an experimental model of MS induced by high fat diet. METHODS: Wistar rats were fed on high fat diet from the fourth week of life, for 20 weeks. The groups received Losartan or Spironolactone from the eighth week of life. We weekly evaluated the body weight and BP by tail plethysmography. At the end of the experiment oral glucose tolerance, lipid profile, creatinine clearance tests, and the direct measurement of BP were performed. A morphometric kidney analysis was performed. RESULTS: The administration of high-fat diet was associated with the development of MS, characterized by central fat accumulation, hypertension, hyperglycemia and hypertriglyceridemia. In this model there were no changes in renal histomorphometry. The blockade of angiotensin II (Ang II) receptor AT1 prevented the development of hypertension. The mineralocorticoid blockage did not have antihypertensive efficacy but was associated with reduction of abdominal fat. CONCLUSION: The dissociation of the antihypertensive response to the blockades of Ang II receptors and mineralocorticoid indicates the involvement of Ang II in the pathogenesis of hypertension associated with obesity. Reduction of central obesity with Spironolactone suggests the presence of mineralocorticoid adipogenic effect.

[Effect of ipriflavone on Wistar rats and their litters]. / Efeito da ipriflavona sobre ratas Wistar e suas ninhadas.

PURPOSE: Evaluate the effects of ipriflavone during fetogenesis, since no studies have been conducted to assess its effect during this period. METHODS: 60 pregnant rats were divided randomly into four groups (n=15). G-control (1 mL of distilled water) and three groups treated intragastrically with ipriflavone from the 16th to the 20th post coitus (PC) day: G-300 (300 mg/kg), G-1,500 (1,500 mg/kg) and G-3,000 (3,000 mg/kg). The animals were weighed, anaesthetized intraperitoneally with xylazine and ketamine at doses of 180 mg/kg and 10 mg/kg, respectively, and sacrificed by total exsanguination on the 21st day. A complete blood count was performed and serum cholesterol, triglycerides, AST, ALT, urea, creatinine, and glucose were determined in pregnant rats. After laparotomy, the liver, kidneys, adrenals, spleen and ovaries were removed and weighed; fetuses and placentas were also weighed to obtain the average weight of the litters. Four fetuses (two males and two females) were chosen at random for the determination of the length and weight of brain, liver, kidneys and lungs. STATISTICAL ANALYSIS: ANOVA followed by Dunnett's test. For raw data without normal distribution and homoscedasticity, we used the Kruskal-Wallis test followed by the Mann-Whitney test. Proportions were analyzed by the χ² test (p<0.05). RESULTS: Triglyceride levels (mg/dL) were: Control-G (138.8±21.8), G-300 (211.2±63.9) G-1,500 (251.5±65.2) G-3,000 (217.7±49.6); p<0.05. The body weight of fetuses (g) was: G-Control (male 3.3±0.3; female 3.1±0.3), G-300 (male 3.4±0.2; female 3.1±0.4), G-1,500 (male 3.5±0.3; female 3.2±0.3), G-3,000 (male 3.4±0.5; female 3.1±0.4). CONCLUSION: Ipriflavone did not cause maternal toxicity, but increased triglyceride levels and reduced hematocrit at higher doses. The body and organ weights of the fetuses did not change with dam treatment. There were no external malformations or fetal deaths.

Efeito da ipriflavona sobre ratas Wistar e suas ninhadas / Effect of ipriflavone on Wistar rats and their litters

OBJETIVO: Avaliar os efeitos da ipriflavona durante a fetogênese, já que não foram encontrados estudos visando avaliar seu efeito durante este período. MÉTODOS: Foram utilizadas 60 ratas prenhes, distribuídas aleatoriamente em quatro grupos (n=15). G-controle (1 mL de água destilada) e três grupos tratados com ipriflavona, via intragástrica, do 16º ao 20º dia pós-coito (PC): G-300 (300 mg/kg), G-1500 (1.500 mg/kg) e G-3000 (3.000 mg/kg). Os animais foram pesados e sacrificados no 21º dia por exsanguinação total sob anestesia (xilazina (10 mg/kg) e quetamina (90 mg/kg) via intraperitoneal. Foi realizado hemograma completo e dosagens séricas de colesterol, triglicérides, AST, ALT, ureia, creatinina e glicose das ratas prenhes. Após laparotomia foram removidos e pesados fígado, rim, suprarrenais, baço e ovários; os fetos e placentas foram pesados obtendo-se o peso médio das ninhadas. Quatro fetos (dois machos e duas fêmeas) por mãe foram aleatoriamente designados para obter-se o comprimento e peso de cérebro, fígado, rins e pulmões. Para a análise estatística utilizou-se o teste ANOVA seguido do teste de Dunnet; para dados não homocedásticos e sem distribuição normal, foi usado o teste de Kruskal-Wallis, seguido de Mann-Whitney; as proporções foram analisadas pelo teste do χ² (p<0,05) RESULTADOS: Níveis de triglicérides (mg/dL): G-Controle (138,8±21,8); G-300 (211,2±63,9); G-1500 (251,5±65,2); G-3000 (217,7±49,6); p<0.05. Peso corporal dos fetos (g): G-Controle (machos 3,3±0,3; fêmeas 3,1±0,3); G-300 (machos 3,4±0,2; fêmeas 3,1±0,4); G-1500 (machos 3,5±0,3; fêmeas 3,2±0,3); G-3000 (machos 3,4±0,5; fêmeas 3,1±0,4). CONCLUSÃO: A ipriflavona não causou toxicidade materna, mas elevou níveis de triglicérides e reduziu o hematócrito em doses elevadas, o tamanho, peso corporal e de órgãos fetais não foram alterados. Não foram observadas malformações externas nem mortes fetais.

PURPOSE: Evaluate the effects of ipriflavone during fetogenesis, since no studies have been conducted to assess its effect during this period. METHODS: 60 pregnant rats were divided randomly into four groups (n=15). G-control (1 mL of distilled water) and three groups treated intragastrically with ipriflavone from the 16th to the 20th post coitus (PC) day: G-300 (300 mg/kg), G-1,500 (1,500 mg/kg) and G-3,000 (3,000 mg/kg). The animals were weighed, anaesthetized intraperitoneally with xylazine and ketamine at doses of 180 mg/kg and 10 mg/kg, respectively, and sacrificed by total exsanguination on the 21st day. A complete blood count was performed and serum cholesterol, triglycerides, AST, ALT, urea, creatinine, and glucose were determined in pregnant rats. After laparotomy, the liver, kidneys, adrenals, spleen and ovaries were removed and weighed; fetuses and placentas were also weighed to obtain the average weight of the litters. Four fetuses (two males and two females) were chosen at random for the determination of the length and weight of brain, liver, kidneys and lungs. Statistical analysis: ANOVA followed by Dunnett's test. For raw data without normal distribution and homoscedasticity, we used the Kruskal-Wallis test followed by the Mann-Whitney test. Proportions were analyzed by the χ² test (p<0.05). RESULTS: Triglyceride levels (mg/dL) were: Control-G (138.8±21.8), G-300 (211.2±63.9) G-1,500 (251.5±65.2) G-3,000 (217.7±49.6); p<0.05. The body weight of fetuses (g) was: G-Control (male 3.3±0.3; female 3.1±0.3), G-300 (male 3.4±0.2; female 3.1±0.4), G-1,500 (male 3.5±0.3; female 3.2±0.3), G-3,000 (male 3.4±0.5; female 3.1±0.4). CONCLUSION: Ipriflavone did not cause maternal toxicity, but increased triglyceride levels and reduced hematocrit at higher doses. The body and organ weights of the fetuses did not change with dam treatment. There were no external malformations or fetal deaths.

[Dissociation of antihypertensive and metabolic response to losartan and spironolactone in experimental rats with metabolic sindrome]. / Dissociação da resposta anti-hipertensiva e metabólica à losartana e espironolactona em ratos com síndrome metabólica experimental.

INTRODUCTION: The treatment of arterial hypertension (AH) in patients with metabolic syndrome (MS) is a challenge, since non drug therapies are difficult to implement and optimal pharmacological treatment is not fully established. OBJECTIVE: To assess the blockade of the rennin angiotensin aldosterone system (RAAS) in blood pressure (BP) in renal function and morphology in an experimental model of MS induced by high fat diet. METHODS: Wistar rats were fed on high fat diet from the fourth week of life, for 20 weeks. The groups received Losartan or Spironolactone from the eighth week of life. We weekly evaluated the body weight and BP by tail plethysmography. At the end of the experiment oral glucose tolerance, lipid profile, creatinine clearance tests, and the direct measurement of BP were performed. A morphometric kidney analysis was performed. RESULTS: The administration of high-fat diet was associated with the development of MS, characterized by central fat accumulation, hypertension, hyperglycemia and hypertriglyceridemia. In this model there were no changes in renal histomorphometry. The blockade of angiotensin II (Ang II) receptor AT1 prevented the development of hypertension. The mineralocorticoid blockage did not have antihypertensive efficacy but was associated with reduction of abdominal fat. CONCLUSION: The dissociation of the antihypertensive response to the blockades of Ang II receptors and mineralocorticoid indicates the involvement of Ang II in the pathogenesis of hypertension associated with obesity. Reduction of central obesity with Spironolactone suggests the presence of mineralocorticoid adipogenic effect.