Prolonged cerebellin administration inhibits the growth, but enhances steroidogenic capacity of rat adrenal cortex.

Cerebellin is a 16-amino acid peptide, that has been previously found to acutely stimulate steroid secretion from rat adrenal cortex in vivo and in vitro. We have investigated the effects of a prolonged cerebellin treatment (daily injections of 15 nmoles/kg for 6 consecutive days) on the growth and secretion of rat adrenal cortex. Cerebellin lowered adrenal weight, and morphometry showed that this was due to the decrease in the volume of each adrenocortical zone exclusively ensuing from the reduction in the number of its parenchymal cells. Cerebellin did not alter plasma concentration of ACTH, but it raised the levels of circulating aldosterone and corticosterone. The conclusion is drawn that cerebellin chronic administration evokes a marked hypoplastic atrophy of rat adrenocortical cells, that is coupled with an enhanced ACTH-independent steroidogenic capacity of the remaining parenchymal cells.