Alanine Turnover in Normal and Diabetic Dogs

Summary

The rate of turnover of alanine was determined in normal and insulin-deprived pancreatectomized dogs using a primed constant infusion of U^-14 C-alanine. In the diabetic group, alanine levels and turnover rates were closely correlated suggesting that alanine production is a major determinant of its concentration. Alanine metabolism varied according to the degree of hyperglycaemia: when glucose levels were < 22 mmol/l, alanine fluxes and concentrations remained normal as observed in previously published studies. In contrast, when glucose levels exceeded 25 mmol/l, alanine concentrations and fluxes tended to be markedly elevated (up to 4-5 times the normal values). This finding suggests that in severely hyperglycaemic animals in which hepatic glucose production is likely to be strikingly elevated, an excessive rate of transport of alanine from muscle to the liver might contribute to the accelerated rate of gluconeogenesis.

Key-Words:

Diabetes - Pancreatectomy - Alanine Turnover - ¹⁴C-Alanine - Gluconeogenesis - Glutamine