Acute effects of alpha-MSH on the rat zona glomerulosa in vivo.
alpha-MSH acutely enhanced the plasma concentration of aldosterone (but not that of corticosterone) in the rat, with a maximal response at a dose of 100 micrograms/kg. This dose of alpha-MSH increased the blood level o aldosterone and the activity of 11 beta-hydroxylase and 18-hydroxylase of capsular adrenals in rats infused for 24 h with dexamethasone, dexamethasone plus ACTH, or captopril plus angiotensin II, but not in animals treated with captopril alone. The plasma concentration of corticosterone and the activity of 11 beta-hydroxylase in the inner adrenal layers were not changed. These findings indicate that alpha-MSH is specifically involved in the acute stimulation of the late steps of the secretory activity of the rat zona glomerulosa, and that this action of alpha-MSH requires a normal level of circulating angiotensin II.
D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000097:blood; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D003345:Corticosterone / Q000097:blood; D019405:Cytochrome P-450 CYP11B2; D003907:Dexamethasone / Q000494:pharmacology; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013252:Steroid 11-beta-Hydroxylase / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000378:metabolism
D000804:Angiotensin II; D000450:Aldosterone; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D002216:Captopril; D013250:Steroid Hydroxylases; D019405:Cytochrome P-450 CYP11B2; D013252:Steroid 11-beta-Hydroxylase; D003345:Corticosterone