Urinary aldosterone excretion rate and plasma aldosterone concentration in the rat: effect of ACTH, DOC, furosemide and of changes in sodium balance.
In rats kept under standard conditions urinary aldosterone exretion rate (UAER) and plasma aldosterone concentration (PAC) showed a circadian rhythm with peak values at the beginning of the dark perioith a single dose of DOC (2 mg/kg sc) or given saline as drinking water UAER and PAC decreased to very low levels. Restriction of dietary sodium for 5 weeks increased UAER and PAC 60-fold and 100-fold, respectively. Treatment with ACTH (250 or 500 microng/kg iv) stimulated UAER 8 h following injection and PAC 1 h after injection. In rats treated with a single dose of furosemide (25 mg/kg sc) PAC increased to maximal values within 90 min and reached control values within 24 h. Twenty-four hours-UAER also increased after furosemide treatment. UAER paralleled PAC under all experimental conditions tested. Therefore, our results suggest that UAER is a reliable index of the activity of the renin-angiotensin-aldosterone system in rats under conditions of low and high aldosterone secretion. Measurement of UAER is a useful tool for studies on aldosterone levels in rats over a long period of time.
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000450:Aldosterone / Q000097:blood / Q000378:metabolism* / Q000652:urine; D000818:Animals; D002940:Circadian Rhythm; D003900:Desoxycorticosterone / Q000494:pharmacology*; D004039:Diet, Sodium-Restricted; D005665:Furosemide / Q000494:pharmacology*; D008297:Male; D051381:Rats; D012965:Sodium Chloride / Q000652:urine; D014882:Water-Electrolyte Balance / Q000187:drug effects
D003900:Desoxycorticosterone; D012965:Sodium Chloride; D000450:Aldosterone; D005665:Furosemide; D000324:Adrenocorticotropic Hormone