[Age-related characteristics of the effect of insulin on the membrane potential of cells of the zona fasciculata of the adrenal cortex].

The value of the membrane potential of adrenocorticocytes (ACC) in zona fasciculata of isolated adrenal (IA) cortex and the activity of Na, K-ATPase of IA homogenate is determined in adult (6-7 months) and old (26-28 months) male Wistar rats. No significant age differences are found in the above indices. Administration of insulin in vivo (1.6 U/kg) and in vitro (0.1 U/ml) induced hyperpolarization of ACC plasmic membranes. Insulin increases the activity of Na, K-ATPase of IA in animals of both age groups. Ouabain and actinomycin D blocks the insulin-induced hyperpolarization of ACC, while 2-aminopyridine has no effect on this process. Insulin effect on the MP of IA ACC is less pronounced in old vs. adult animals.