Acute and chronic effect of ethanol on (Na + K)-ATPase activity and cyclic AMP response to vasopressin in rat papillary collecting duct cells.

1. We evaluated the effects of ethanol on (Na + K)-ATPase activity and cAMP response to vasopressin in native and cultured rat papillary collecting duct (PCD) cells. 2. A significant increase in (Na + K)-ATPase and Mg(2+)-ATPase activities was found in PCD cells either isolated from chronic ethanol-fed rats or cultured in the presence of ethanol. 3. Acute treatment with ethanol resulted in a biphasic effect on the activity of (Na + K)-ATPase, which was enhanced below 1% ethanol and inhibited at higher concentrations. 4. Chronic ethanol treatment did not change the cAMP response of PCD cells to vasopressin. Acutely, in turn, this response was enhanced by ethanol per se. 5. It is suggested that the antinatriuretic effect of ethanol could be at least in part mediated by a (Na + K)-ATPase enhancement in PCD cells. Acutely, ethanol could normalize water balance by its peripheral effects on distal nephron.