Glycemia recovery with oral amino acid administration during experimental short-term insulin-induced hypoglycemia

Abstract

Aim The acute effects of the oral administration of l-alanine ( l-ala), l-glutamine ( l-gln), l-ala+ l-gln, and l-alanyl- l-glutamine (AGP) on glycemia recovery during short-term insulin-induced hypoglycemia (IIH) were compared. Methods For this purpose, the blood glucose levels of 24-h-fasted rats that received intraperitoneal injections of regular insulin (IIH group) or saline [control (COG) group] and, 15 min later, oral administration of l-ala (100 mg/kg), l-gln (100 mg/kg), l-ala (50 mg/kg)+ l-gln (50 mg/kg), or AGP (100 mg/kg) were compared. Liver perfusion experiments and blood collection to measure blood glucose levels were performed 30 min after insulin (1.0 U/kg) or saline injection. Livers from the IIH and COG groups were perfused with saturating concentrations of l-ala, l-gln, l-ala+ l-gln, or AGP, and the maximal hepatic production of glucose, urea, ammonia, l-lactate, and pyruvate was evaluated. Results In contrast with l-gln, l-ala+ l-gln, or AGP, the oral administration of l-ala promoted glycemia recovery. In agreement with these results, livers from IIH rats showed maximal hepatic production of glucose and urea from l-ala with 50% of the amount used to obtain the maximal hepatic production of glucose and urea in livers from COG rats. In contrast with l-gln, l-ala+ l-gln, or AGP, the maximal hepatic production of urea from l-ala occurred in the absence of ammonia accumulation. Conclusion The results indicate that the best glycemia recovery promoted by the oral administration of l-ala was a consequence of the higher efficiency of the livers from IIH rats in producing glucose from l-ala.