Studies on the mechanism underlying the influence of alanine infusion on glucose dynamics in the dog

L. Sacca, B. Trimarco, G. Perez, F. Rengo

Research output: Contribution to journalArticle

Abstract

These experiments have been designed to study the influence of alanine infusion on glucose dynamics in the dog and to further elucidate the role of pancreatic hormones in the interaction of alanine with glucose homeostasis. The primed constant infusion of glucose-2-t was used in order to quantitate the rates of glucose production by the liver (Ra) and glucose utilization (Rd). In a first group of experiments, the intravenous infusion of alanine at the rate of 2 mg./kg./min. produced a moderate enhancement of plasma insulin (IRI), while pancreatic glucagon (IRG) increased more consistently. This different pattern of IRI and IRG response caused the insulin/glucagon molar ratio to decline progressively throughout the experiment. Both rates of glucose turnover increased significantly during alanine infusion. Since Ra rose more rapidly than Rd did initially, hyperglycemia developed. Later, glucose production slowly decreased and, in spite of the sustained hyperglucagonemia, reached levels very close to the baseline in the second part of the experiment. A significant direct correlation between Ra and IRG was found, while the changes in Ra correlated inversely with those in L/G molar ratio. In a second group of experiments, alanine was infused at the same dose together with 0.4 μg./kg./min. of cyclic somatostatin. In the first part of the infusion, IRG fell more than IRI did, so that I/G ratio increased. Later, IRI levels maintained at low values while IRG returned slowly to the baseline and consequently I/G ratio significantly decreased. Glucose production fell rapidly soon after the beginning of the infusion, and therefore hypoglycemia developed. Later, Ra increased progressively to levels above baseline and plasma glucose returned to the preinfusion levels. As in the first group of experiments, a significant direct correlation between Ra and IRG and an inverse correlation between the changes in Ra and I/G ratio were observed. These experiments demonstrate that alanine infusion produces an acceleration of glucose turnover and that a clear interrelationship between the release of glucose by the liver and the mobilization of pancreatic hormones exists. Finally, the experiments with somatostatin indicate that hyperglucagonemia is one of the mechanisms underlying the stimulatory effect of alanine on glucose production.

Original languageEnglish
Pages (from-to)262-270
Number of pages9
JournalDiabetes
Volume26
Issue number4
Publication statusPublished - 1977

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Internal Medicine

Fingerprint Dive into the research topics of 'Studies on the mechanism underlying the influence of alanine infusion on glucose dynamics in the dog'. Together they form a unique fingerprint.

  • Cite this

    Sacca, L., Trimarco, B., Perez, G., & Rengo, F. (1977). Studies on the mechanism underlying the influence of alanine infusion on glucose dynamics in the dog. Diabetes, 26(4), 262-270.