Evidence that endogenous somatostatin (SRIF) exerts a tonic inhibitory effect on the rat renin--angiotensin--aldosterone system.
The bolus ip. administration of a SRIF antagonist (SRIF-A) (60 nM/rat) significantly increased renin activity (PRA) and plasma aldosterone concentration (PAC) in rats, without affecting natremia, kalaemia and the blood levels of ACTH or corticosterone. SRIF-A also raised PAC in rats whose renin-angiotensin system had been pharmacologically interrupted by combined captopril/angiotensin-II infusion and in which PRA was very low. The ip. injection of an equimolar dose of SRIF completely reversed these effects of SRIF-A, but the administration of SRIF alone did not affect either PRA or PAC. Taken together, these data would suggest that, in the rat, endogenous SRIF exerts, under basal conditions, a two-fold maximum tonic inhibitory effect on both renin release by kidneys and aldosterone secretion by zona glomerulosa cells.
Department of Anatomy, University of Padua, Italy.
G
G
Mazzocchi
L K
LK
Malendowicz
V
V
Meneghelli
G G
GG
Nussdorfer
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000450:Aldosterone / Q000097:blood / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D003345:Corticosterone / Q000097:blood; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011188:Potassium / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000378:metabolism*; D012084:Renin-Angiotensin System / Q000187:drug effects*; D012964:Sodium / Q000097:blood; D013004:Somatostatin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D015384:Zona Glomerulosa / Q000187:drug effects / Q000378:metabolism
D000804:Angiotensin II; D000450:Aldosterone; D013004:Somatostatin; C020948:somatostatin, Trp(8)-Cys(14)-; D000324:Adrenocorticotropic Hormone; D002216:Captopril; D012964:Sodium; D012083:Renin; D011188:Potassium; D003345:Corticosterone