Investigations on the effects of long-term administration of a methionine-enkephalin analogue on the adrenal zona fasciculata of rats treated with dexamethasone or dexamethasone and ACTH.
Prolonged (7 days) methionine-enkephalin (DALA) treatment provoked a dose-dependent increase in the volume of zona fasciculata cells of dexamethasone-administered rats, along with a notable rise in the plasma concentration of corticosterone and the activity of 11 beta-hydroxylase. Comparable dose-dependent effects were observed after chronic administration of ACTH to dexamethasone-suppressed rats. The chronic administration of the maximum dose of DALA (500 micrograms/kg/day) was found to significantly further the trophic action of ACTH on the zona fasciculata of dexamethasone-treated animals. It is suggested that enkephalins act independently of and synergistically with ACTH in stimulating the growth and steroidogenic capacity of the rat adrenal zona fasciculata.
D000302:Adrenal Cortex / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D003345:Corticosterone / Q000097:blood; D003907:Dexamethasone / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013252:Steroid 11-beta-Hydroxylase / Q000378:metabolism; D013997:Time Factors
D004744:Enkephalin, Methionine; C022118:enkephalinamide-Met, Ala(2)-; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D013252:Steroid 11-beta-Hydroxylase; D003345:Corticosterone