Effects of L-alanyl-glutamine upon in vivo metabolites concentrations in rats subjected to hind limb ischemia followed by reperfusion

A study has been conducted to investigate the effects of L-alanyl-glutamine upon blood and tissue concentrations of metabolites (pyruvate, lactate, glucose, acetoacetato, 3-hydroxybutyrate, ketone bodies and ATP) in Wistar rats subjected to ischemia/reperfusion of hind limb. Ninety-six adult male rats were randomized in 4 groups and pre-treated with saline 2.0 mL (G-1,G-3) or L-alanyl-glutamine solution 0.75 mgKg-1(G-2, G-4) during 7 days. One-hour after the last gavage all rats were submitted to clamping of the left iliac artery or sham operation. The clamp was removed after 3 h; sham rats were operated once more. Muscle, liver, kidney and blood samples were collected at the end of ischemia and at 1-3-6 h during reperfusion. Metabolites were submitted to enzymatic analyses. Results were expressed as Mean ± S.E.M. Non-parametric tests (Mann-Whitney and Kruskal-Wallis/Dunn) were utilized for statistical analyses. P<0.05 was accepted as significant. Lactate, pyruvate and glucose concentrations did not increase during ischemia or reperfusion in rats pre-treated with saline (G-1 vs. G-2). On the other hand ketone bodies concentrations were decreased in T-0 and blood glucose was elevated during reperfusion. Liver lactate and muscle glucose were increased and lactate concentration was decreased in L-alanyl-glutamine pre-treated rats. Ketone bodies were elevated in the liver, muscle and blood and renal lactate was also elevated in the aforementioned rats. It is concluded that the model utilized in this study promotes significant metabolic alterations due to ischemia/reperfusion injury. L-Ala-Gln dipeptide induced increased hepatic lactate and muscle glucose concentrations and decreased of muscle lactate concentrations point out to increased turnover of glucose. L-Ala-Gln also induced increased ketogenesis, ketonemia and ketone bodies uptake during reperfusion along with increased lactacidemia and kidney lactate concentrations. Increased glycolytic activity in peripheral tissues via malate-aspartate shuttle activation lead to decreased insulin resistance with possible decrease in plasma insulin levels and increased ketogenesis.Foram investigados os efeitos metabólicos da L-alanil-glutamina nas concentrações sanguíneas e teciduais dos metabólitos (piruvato, lactato, glicose, acetoacetato, 3-hidroxibutirato, corpos cetônicos e ATP) em ratos Wistar submetidos à isquemia/reperfusão do membro pélvico. Utilizaram-se 96 ratos adultos, machos, distribuídos aleatoriamente em 4 grupos numericamente iguais e pré-tratados com solução salina 2,0 mL (G-1 e G-3) ou L-alanil-glutamina 0,75 g Kg-1(G-2 e G-4), durante 7 dias. Uma hora após a última gavagem, todos os ratos foram submetidos ao pinçamento da artéria ilíaca esquerda ou operação simulada. Após 3 horas a pinça foi removida; nos grupos simulados realizou-se nova intervenção cirúrgica. Amostras (músculo, fígado, rim e sangue) foram coletadas ao final da isquemia máxima (T-0) e durante a reperfusão (1, 3 e 6h). Os metabólitos foram determinados por ensaio enzimático e expressos como Média ± E.P.M. Testes não paramétricos (Mann-Whitney e Kruskal-Wallis/Dunn) foram utilizados para a análise estatística. O nível de significância foi de p