Re-evaluation of the role of aldosterone in mechanism of natriuresis induced by extracellular fluid volume expansion.
Acute experiments were performed in thiobarbiturate (Inactin, PROMONTA) anaesthesia in 21 male rats. It was found that the attenuation of the antinatriuretic effect of aldosterone by a spironolactone Aldactone (BOEHRINGER) in a dose of 10 mg per rat in 1 h i.v. enhanced urine (V) and sodium (UNaV) excretion following the extracellular fluid volume expansion (ECFV) with intravenous infusion of saline. Max. V = 81.44 +/- +/- 7.46 mul min-1 was obtained in Aldactone treated rats as compared to 54.95 + 7.24 mul min-1 in controls: UNaV = 9.89 +/- 1.26 muval min-1 vs. 6.17 +/- 0.73 muval min-1, respectively. The urinary Na/K ratio was also significantly higher in the same samples of Aldactone treated rats (6.15 +/- +/- 1.22 vs. 2.68 +/- 0.19). It is concluded that endogenous aldosterone blunts nriuresis induced by the ECFV expansion.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004231:Diuresis / Q000187:drug effects; D005919:Glomerular Filtration Rate / Q000187:drug effects; D007263:Infusions, Parenteral; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009318:Natriuresis / Q000187:drug effects*; D011188:Potassium / Q000652:urine; D051381:Rats; D012964:Sodium / Q000652:urine; D012965:Sodium Chloride / Q000494:pharmacology; D013148:Spironolactone / Q000494:pharmacology*; D014882:Water-Electrolyte Balance / Q000187:drug effects*
D013148:Spironolactone; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium