CHRONIC ETHANOL INGESTION MODIFIES THE RENIN-ALDOSTERONE AXIS INDEPENDENT OF ALTERATIONS IN THE REGULATION OF ATRIAL-NATRIURETIC-PEPTIDE

Using an animal model, we have investigated the effects of chronic eth anol ingestion on the regulation of atrial natriuretic peptide (ANP) s ynthesis and release. Male Sprague-Dawley rats were maintained for 6 w eeks on a liquid diet of ethanol (up to 20% v/v) as part of a 2% solut ion of calf milk replacer. Weight-matched controls received an equal v olume of ethanol-free solution, and normal animals drank ad libitum. A ll animals received rat chow throughout the experiment. This model pro duced physiologically relevant levels of blood ethanol, as concentrati ons at the time of sacrifice were 171.98 +/- 39.26 mg/dl. Plasma renin activity was significantly elevated in response to ethanol treatment, whereas circulating aldosterone concentration was reduced. No alterat ions in the plasma or atrial tissue levels of ANP were evident, althou gh we did observe a significant increase in the ventricular tissue lev els of ANP from 45.1 to 71.8 ng/g as a consequence of ethanol treatmen t. Levels of both atrial and ventricular ANP mRNA were not different b etween alcohol-treated and liquid-restricted control animals, although both groups showed significant increases in the amount of transcript in comparison with rats drinking ad libitum. No significant increases in either arterial blood pressure or heart/body weight ratio were obse rved for ethanol-treated rats. These results suggest that modification s in the renin-aldosterone axis can occur independently of alterations in the regulation of ANP under the influence of chronic ethanol inges tion.