Metabolism of Glucose, Fructose and Pyruvate in Tissues of Weanling Rats with Hypothalamic Obesity

Abstract

Tissues from weanling rats with hypothalamic obesity (VMN) were incubated with U^-14C glucose at various substrate concentrations, with U^-14C fructose in the presence and absence of unlabeled glucose, with 1^-14C and 6^-14C glucose, with 1^-14C pyruvate and with 2^-14C pyruvate at various substrate concentrations. U^-14C glucose utilization by VMN rat adipose tissue was greater than normal at all glucose concentrations and this difference became more pronounced as substrate concentration was increased. Both 1^-14C and 6^-14C glucose were oxidized and incorporated into fatty acids and glycogen more rapidly by VMN than by normal rat adipose tissue. Pyruvate incorporation into glyceride-glycerol and glyceride fatty acids and oxidation of 2^-14C pyruvate through the Krebs cycle were decreased at all concentrations in VMN rat adipose tissue. Fructose oxidation and incorporation into glyceride-glycerol was greater than normal in VMN rat adipose tissue in the absence but not the presence of glucose. The rate of fructose oxidation was smaller in diaphragms from VMN rats than in those of the controls.

Key words

Hypothalamic Obesity - Glucose - Fructose - Pyruvate - Glycogen - Adipose Tissue - Diaphragm