Effect of ACTH on the proliferation of the rat adrenal gland

Abstract

Although the regulation of steroidogenesis in adrenal fasciculata and reticularis is stimulated by adrenocorticotrophic hormone (ACTH), its role on the proliferation of adrenocortical cell is not established. We thus investigated the effect of ACTH on the proliferation of adrenocortical cells by analyzing the expression of proliferating cell nuclear antigen (PCNA). Endogeneous secretion of ACTH was inhibited by treatment with dexamethasone for 5 days. At intervals after ACTH treatment, homogenate of the adrenal gland was subjected to Western blot analysis. PCNA expression was detected in control rat without any treatment. Dexamethasone administration for 5 days resulted in the reduction of PCNA expression. ACTH administration to the dexamethasone treated rats increased PCNA expression at 24 hr. It is thus demonstrated that ACTH increases cellular proliferation in aderenal cortex.