Stimulation by alcohols of cyclic AMP metabolism in human leukocytes. Possible role of cyclic AMP in the anti-inflammatory effects of ethanol

Abstract

In this study ethanol and certain other short-chain aryl (benzyl and phenethyl) and aliphatic (methyl, propyl, butyl, and amyl) alcohols produced up to 10-fold increases in cyclic AMP (cAMP) concentrations in purified human peripheral blood lymphocytes. Ethanol concentrations as low as 80 mg/dl produced significant elevations in lymphocyte cAMP. Significant but less marked augmentation of cAMP in response to alcohols was observed in human platelets, human granulocytes, and rabbit alveolar macrophages. The mechanism of the alcohol-induced cAMP accumulation is probably secondary to membrane perturbation and consequent activation of adenylate cyclase, because ethanol directly stimulated this enzyme in lymphocyte membrane preparations but had no effect on lymphocyte phosphodiesterase activity. Lysosomal enzyme release, by phagocytosing human leukocytes, and aminoisobutyric acid transport in mitogen-stimulated human lymphocytes were shown to be inhibited by ethanol and other alcohols at concentrations which also elevate cAMP. In general, the magnitude of the inhibition of these inflammatory processes correlated with the ability of the alcohol to elevate cAMP concentrations. Lectin-and anti-thymocyte globulin-induced lymphocyte mitogenesis was inhibited or unaffected depending upon both the concentration and type of mitogenic stimulus and the concentration and type of alcohol utilized. Inflammatory mediator release from rat mast cells also was inhibited by ethanol and certain other alcohols, but whole cell cAMP was not increased. Ethanol may alter these inflammatory responses and other biologic processes at least in part by modulating cellular levels of cAMP.