Polyunsaturated fatty acids and ethanol.

Ethanol exposure leads to a loss in membrane polyunsaturated fatty acids (PUFA). It is proposed that polyunsaturated species of phospholipids are not randomly distributed, but are concentrated in the cytosolic leaflets of the plasma membrane and are preferentially associated with membrane proteins. These lipids affect the physical state of environments surrounding membrane proteins and thereby serve to regulate many cellular functions. Disruption of these environments may occur even when a small percentage of total polyunsaturates is lost due to ethanol exposure. One possible mechanism of ethanol-induced polyunsaturate loss may be activation of a phospholipase A2 enzyme which is selective for these species of phospholipids. Fatty acids released would stimulate the production of prostaglandins and/or leukotrienes. Similarly, the released docosahexaenoate can be metabolized by rat brain to leukotriene-like compounds which are biologically active in smooth muscle systems. This metabolism is stimulated by ethanol in human platelets, in vitro.