Effect of ethanol treatment on the activity and amount of stimulatory GTP-binding regulatory protein (Gs) in S49 murine lymphoma cells and human erythrocytes.

Abstract

Treatment of wild-type S49 murine lymphoma cells with 50 mM ethanol for 24 hr caused a 14% decrease in the Gs activity (an ability to compensate the deficiency of stimulatory GTP-binding regulatory protein, Gs, in membrane from CYC-S49 murine lymphoma cells) and a 29% decrease in the amount of alpha-subunit of Gs, Gs alpha. The Gs activity also decreased by treatment of the cells with methanol, propan-1-ol and butan-1-ol with an increasing efficiency according to the carbon chain length of each alcohol. A metabolite of ethanol, acetate, showed no reduction in either the Gs activity or the amount of Gs alpha. The Gs activity in membrane preparations from S49 cells was stable in a solution containing 50-250 mM ethanol or 0.01-10 mM acetaldehyde. When human erythrocytes were treated with 50 or 100 mM ethanol under the same conditions used for S49 cells, the Gs activity did not decrease but rather increased slightly, without any change in the Gs alpha content. These results indicate that the reduction in Gs activity and in Gs alpha content depends on the altered metabolism of S49 cells that can be induced by ethanol itself. Human erythrocytes lack such a responsiveness.