Ethanol-induced water diuresis is not prostaglandin dependent

Previous studies have demonstrated an effect of alcohol on arachidonic acid metabolism. These studies were undertaken to determine if the water diuresis of alcohol is due to enhanced prostaglandin E2 (PGE2) production, a known antidiuretic hormone antagonist. 6 rabbits, weighing between 2.5 and 3.2 kg, were studied in standard metabolic cages during 4 periods: control, indomethacin administration, ethanol administration, and ethanol and indomethacin. 10 ml of 100% alcohol was added to their water in periods 3 and 4, and 5 mg/kg indomethacin was given during periods 2 and 4. We recorded urine output, urine osmolality, sodium excretion, potassium excretion, and PGE2 excretion. Urine flow rate significantly increased in periods 3 and 4 from 79 +/- 7 to 177 +/- 13 and 165 +/- 11 cm3/day, respectively, p less than 0.001 for both, compared to control. Indomethacin, therefore, did not prevent the water diuresis. Urinary PGE2 excretion was low (125 +/- 13 ng/day) with ethanol administration compared to control (897 +/- 71 ng/day, p less than 0.001). Levels were similar to those seen with the inhibitor indomethacin (105 +/- 22 ng/day, n.s.). These low levels with ethanol were observed at the same time of the significant free water diuresis. We conclude that the water diuresis produced by acute ethanol administration is not mediated by enhanced renal PGE2 production.