Hormonal determinants of sodium excretion in rats with experimental high-output heart failure.
The present study evaluates the inter-relationship between the alteration in atrial natriuretic factor (ANF) and the renal handling of Na in rats with chronic aortocaval (a-v) fistula, an experimental model of congestive heart failure. Balance studies in these animals showed two distinct patterns of Na excretion: some rats developed progressive Na retention [urinary sodium excretion (UNaV) less than 100 mueq/24 h], whereas others compensated and returned to normal Na balance (UNaV greater than 1,200 mueq/24 h). Base-line plasma ANF levels were equally elevated in Na-retaining and compensated rats with a-v fistula (588 +/- 70 vs. 621 +/- 114 pg/ml, P, NS). However, the response of the two groups to exogenous administration of synthetic rat ANF-(101-126) in incremental doses varied greatly. ANF infusion increased the fractional Na excretion (FENa) in compensated animals from 0.12 +/- 0.03 to 2.6 +/- 0.5%, whereas the rise in FENa in Na-retaining animals was markedly blunted (0.11 +/- 0.06 to 0.89 +/- 0.35%). A similar pattern of ANF action was observed on the glomerular filtration rate and urine flow. The blunted response to ANF in the Na-retaining animals was associated with a marked increase in plasma renin activity (PRA) (35.6 +/- 6.9 vs. 4.5 +/- 0.7 ng ANG I.ml-1.h-1 in sham control rats, P less than 0.05) and plasma aldosterone levels (729.3 +/- 28.2 vs. 42.6 +/- 18.4 ng/dl in sham control rats, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Winaver
J
J
Department of Physiology, Faculty of Medicine, Technion, Haifa, Israel.
Hoffman
A
A
Burnett
J C
JC
Haramati
A
A
D000450:Aldosterone / Q000097:blood; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001164:Arteriovenous Fistula / Q000503:physiopathology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006333:Heart Failure / Q000503:physiopathology*; D009318:Natriuresis / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System
D000806:Angiotensin-Converting Enzyme Inhibitors; D000450:Aldosterone; D009320:Atrial Natriuretic Factor; D012083:Renin