title: Re-evaluation of the role of aldosterone in mechanism of natriuresis induced by extracellular fluid volume expansion.
abstract: 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.
mesh_terms: 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*
chemical_list: D013148:Spironolactone; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium