Since ethanol ingestion is associated with a disruption of water and e
lectrolyte balance in a variety of species, we sought to evaluate the
regulatory control of atrial natriuretic peptide (ANP) in response to
acute doses of ethanol. Male Sprague-Dawley rats were administered a 5
-g/kg dose of ethanol (40% w/v) via a gastric tube, while control anim
als received an equivalent volume of water. Expressed as a percentage
of control, plasma ANP levels were 39.0%, 28.5%, and 23.6% in the etha
nol-treated animals at 30, 60, and 120 min postintubation, respectivel
y. Ethanol-treated animals displayed blood alcohol concentrations of 8
9.0, 137.6, and 214.1 mg/dl at the same time periods. After 120 min, p
lasma renin activity was elevated from 8.7 to 20.3 ng/ml/h in conjunct
ion with an increase in the levels of circulating aldosterone from 16.
3 to 42.5 ng/dl and an increase in plasma vasopressin from 2.2 to 3.6
pg/ml. Levels of atrial ANP mRNA remained consistent over the time cou
rse of the experiment, and no changes in the amount of ventricular ANP
transcript were observed. Tissue ANP levels were similar between etha
nol-treated and water-loaded control animals. In vitro experiments usi
ng cultured cardiac myocytes suggest that ethanol exposure may not dir
ectly affect ANP secretion. We propose that acute ethanol treatment ma
y inhibit atrial distension and subsequently modify the control of ANP
release under volume loading conditions.