Sodium Dependency of Insulin-Stimulated Glucose Transport in Isolated Fat Cells.

Abstract

The metabolic effects of insulin on muscle and adipose tissue are well established. However, its site and mode of action are still subjected to much discussion. Some tend to explain all its metabolic effects as a consequence of a stimulated transport of specific substrates while others would tend to explain the metabolic actions by a direct stimulation of the enzymatic processes. In fat tissues, it has been shown that glucose transport is a carrier mediated process having the characteristics of facilitated diffusion (1) on which insulin acts, in an unknown fashion, while also favoring K retention and Na efflux (2). In order to investigate the possible relationships between glucose transport and cations on insulin stimulated fat tissue, we have incubated isolated fat cells in the presence of various amounts of the different cations ‘normally found in the body fluids and submitted them to insulin stimulation.