Adrenal enkephalin biosynthesis regulated by glucocorticoid

Denervation of the rat adrenal results in a 10 to 20-fold increase in enkephalin-containing EC peptides 4 days after surgery. This denervation-induced rise in medullary EC peptides is blocked by hypophysectomy (hypox) and partially reinstated by dexamethasone or ACTH treatment. Culture of adrenal medullary explants (glands) for 4 days in serum-free medium without dexamethasone resulted in a 6-fold increase in EC peptides in glands from hypox rats while the addition of dexamethasone (10-5M) produced a 29 fold increase. These results indicate that a loss of depolarizing stimuli produced by denervation in vivo or explanation in vitro initiates a pretranslational event which requires glucocorticoid for the full expression of EC peptide biosynthesis.