Characterization of the lipid composition of washed and percoll gradient centrifuged epididymal mouse sperm.

Abstract

Capacitation is an important yet poorly understood process during which the fluidity of the sperm membrane increases to prepare sperm for the acrosome reaction (AR) and subsequent sperm-egg binding. While cholesterol efflux may be partially responsible for this increase, modification of lipid components, such as remodeling of specific phospholipid (PL) bound unsaturated fatty acyl chains, may also be involved, since no change in the cholesterol:PL molar ratio following capacitation in mouse has been previously described. In this study, lipid classes (cholesterol, PL, sulfogalactosylglycerolipid (SGG), diacylglycerol and triacylglycerol) were quantified and the fatty acyl chain compositions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were characterized in washed non-capacitated (WS), washed capacitated (WCS), and Percoll gradient centrifuged (PGC) capacitated (PGCS) epididymal mouse sperm. Fatty acid methyl esters were generated from PC and PE by acid methanolysis and their identity was analyzed by gas chromatography. (Abstract shortened by UMI.)