Effect of spironolactone on the renin-aldosterone system in rats.
PRA, PRC and the plasma concentration of aldosterone (Aldo) were measured in rats (Sp-rats) receiving a daily sc injection of Spironolactone, (Sp, 20 mg in olive oil) and in control rats (C-rats) receiving olive oil only. Animals were studied one day after starting treatment, 5 days on treatment or after 5 weeks on the study. PRA, PRC and Aldo were significantly increased in Sp-rats as compared to C-rats throughout all the study. In additional Sp-rats and C-rats, the urine volume, serum Na+ and K+ concentration, Na+ and K+ intake and the urinary excretion of Na+, K+ and aldosterone-18-glucuronide (UAldV) were serially measured during 5 weeks. The total radioactivity plasma clearance after an i.v. bolus injection of 3H-aldosterone was subsequently measured in (5 Sp-rats and 5 C-rats). No significant differences in serum Na+ and K+ concentration and in Na+ and K+ balance were observed between Sp-rats and C-rats. UAldV was significantly higher in Sp-rats than in C-rats during all the study. After 5 weeks on treatment the total radioactivity plasma clearance was significantly higher in Sp-rats than in C-rats. These results indicate that Sp, at high dosage, stimulates renin release and aldosterone secretion by a mechanism unrelated to alterations in Na+ and K+ balance.
Jiménez
W
W
Laboratorio de Hormonas y Unidad de Hepatología, Hospital Clínico Provincial, Barcelona, Spain.
Martínez-Pardo
A
A
Arroyo
V
V
Gaya
J
J
Rivera
F
F
D000450:Aldosterone / Q000097:blood* / Q000652:urine; D000818:Animals; D008297:Male; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood*; D012084:Renin-Angiotensin System / Q000187:drug effects; D012964:Sodium / Q000378:metabolism; D013148:Spironolactone / Q000494:pharmacology*
D013148:Spironolactone; D000450:Aldosterone; D012964:Sodium; D012083:Renin; D011188:Potassium