ACUTE ETHANOL INGESTION MODIFIES THE CIRCULATING PLASMA-LEVELS OF ATRIAL-NATRIURETIC-PEPTIDE

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.