Effects of chronic and acute ethanol exposure on renal (Na+K)-ATPase in the rat

1. We evaluated the effects of chronic ethanol consumption on the kinetic properties of renal (Na+K)-ATPase and compared them with acute inhibition by ethanol in vitro. 2. When adult rats were fed 20% ethanol for 10 weeks, renal (Na+K)-ATPase activity increased but the sensitivity of the enzyme to ethanol inhibition in vitro was not altered. 3. V-max was increased by ethanol consumption, whereas K-0.5 and n(H) were not changed. The kinetic parameters of Mg2+-ATPase were not affected under the same conditions. 4. We concluded that ethanol induced tolerance or enhancement of renal (Na+K)-ATPase or both can be explained on the basis of an increase in V-max. (C) 1997 Elsevier Science Inc.