Control of adrenal medullary protein synthesis by corticosteroids

Abstract

It has previously been shown that hypophysectomy decreases the activity of the adrenal medullary enzyme, phenylethanolamine N- methyltransferase , which catalyzes the conversion of norepinephrine to epinephrine. This effect and the consequential decrease in adrenal epinephrine content and secretion can be reversed by treatment with adrenocorticotrophic hormone (ACTH) or glucocorticoids. This report examines the effect of glucocorticoids on adrenomedullary protein synthesis in general. Hypophysectomy causes a profound disaggregation of the polysomes in the rat adrenal and decreases ability of adrenal ribosomes to incorporate amino acids into peptide chains in vitro. Both effects are restored by in vivo treatment with dexamethasone, a potent synthetic glucocorticoid. The reaggregation of adrenal polysomes precedes the phenylethanolamine N- methyltransferase activity.