Countertransport of 3-O-methyl glucose in incubated rat epididymal adipose tissue

Abstract

An incubated rat epididymal adipose tissue preparation was used for evaluation of the transmembrane distribution of 3-O-methyl-14C-glucose as a function of the glucose concentration in the incubation medium. Such steady-state observations were made both in the presence and absence of insulin. The data indicated that in this tissue the magnitude of 3-O-methyl glucose countertransport was quantitatively related to the magnitude of the transmembrane glucose gradient. Furthermore, for any given glucose concentration of the incubation medium the transmembrane glucose gradient was decreased by insulin. This was interpreted as supporting the view that in this tissue the major effect of insulin on glucose uptake is an acceleration of the transport of glucose across the cell membrane.