Effect of a high glucose diet on insulin binding and insulin action in rat adipocytes

Abstract

To elucidate the mechanisms whereby changes in dietary composition affect the action of insulin on glucose metabolism, insulin binding and glucose uptake and oxidation have been studied in epididymal fat pad adipocytes from rats fed high glucose diets for 5 and 10 days. After 5 days, insulin binding was increased, due mainly to an increased number of receptors (3.4×10⁵ vs. 2.4×10⁵ sites per cell) in spite of increased plasma insulin levels (3.0±0.2 vs. 2.1±0.1 μg/l; p5 cells/2h; p<0.01) and the dose-response curve of glucose uptake was shifted to the left. After 10 days, receptor number decreased to the control level and the effect of insulin on glucose uptake and oxidation (% basal) were similar to controls. Thus, in the early stage of high glucose feeding, insulin receptor number, insulin sensitivity of glucose uptake, and insulin responsiveness of glucose oxidation were increased.