In vivo regulation of enzymes controlling aldosterone synthesis in pregnant rats.
There are two main regulatory sites of aldosterone biosynthesis, the early rate-limiting step by the P450scc and the final steps by the P450aldo. We have already demonstrated that, during gestation, activity and mRNA levels of P450aldo are increased. It has been shown that changes in sodium and potassium in the diet modulate the expression of P450aldo in adrenal zona glomerulosa (ZG). In the present study, we compared the effects of low-sodium (Na+) and high-potassium (K+) diet on the expression of enzymes controlling aldosterone synthesis during gestation. Pregnant and nonpregnant rats were randomly assigned to control group or to group receiving low Na+ or high K+ diet during the last week of pregnancy. By the end of the treatment, the two diets induced increases of plasma aldosterone and P450aldo mRNA levels in nonpregnant and pregnant rats. However, plasma renin activity and P450scc mRNA levels were only in the pregnant group fed the low Na+ diet. High K+ diet had no effect on these parameters. We, thus, suggest that the renin-angiotensin system and the enzymes implicated in aldosterone synthesis are differently regulated during gestation.
Brochu
M
M
Research Center Ste-Justine Hospital and Department of Obstetrics-Gynecology, Université de Montréal, Québec, Canada.
Roy-Clavel
E
E
Picard
S
S
St-Louis
J
J
D000450:Aldosterone / Q000096:biosynthesis* / Q000097:blood; D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics; D004032:Diet; D004039:Diet, Sodium-Restricted; D004798:Enzymes / Q000378:metabolism*; D005260:Female; D011188:Potassium / Q000008:administration & dosage* / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012083:Renin / Q000097:blood
D004798:Enzymes; D012333:RNA, Messenger; D000450:Aldosterone; D019405:Cytochrome P-450 CYP11B2; D002786:Cholesterol Side-Chain Cleavage Enzyme; D012083:Renin; D011188:Potassium