Effect of 3':5'-cyclic AMP on glucose transport in rat adipocytes.

An indirect method for obtaining a reliable measure of the rate of glucose transport into adipocytes is described. Evidence is presented that altered levels of 3':5'-cyclic AMP can influence the transport of glucose into adipocytes. When cyclic AMP levels were lowered with antilipolytic agents (insulin, nicotinic acid, or clofibrate), rates of glucose transport were increased. In contrast, when adipose tissue levels of cyclic AMP were elevated by lipolytic hormones or theophylline, glucose transport when cyclic AMP levels were elevated by lipolytic agents. Agents that can raise cyclic AMP but inhibit lipolytic (procaine, amitryptyline, and phenylethylbiguanide) reduced the rate of glucose transport. Other data are presented that are consistent with the conclusion that cyclic AMP inhibits glucose transport into adipocytes.