Determination of acyl-CoA esters and acyl-CoA synthetase activity in mouse brain areas by liquid chromatography-electrospray ionization-tandem mass spectrometry.

The acyl-CoA levels and the acyl-CoA synthetase activities in 7 areas of mouse brain were determined by liquid chromatography-electrospray ionization-tandem mass spectrometry. Twenty-one acyl-CoA esters of C2:0, C4:0, C6:0, C8:0, C10:0, C12:0, C14:1, C14:0, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C20:0, C20:4, C20:5, C22:0, C22:5, C22:6 and C24:0 were detected in the olfactory bulb, cerebral cortex, hippocampus, cerebellum, hypothalamus, midbrain and medulla oblongata. The brain areas contained primarily the acyl-CoAs of the C16:0, C18:0, C18:1, C20:4 and C22:6 species. The relative abundances of the acyl-CoAs of C16:0, C18:0 and C18:1 were considerably higher than those of C20:4 and C22:6. The levels of medium-chain acyl-CoAs were only 1.2% that of the long-chain acyl-CoAs. The differences in the acyl-CoA synthetase activities in each area of mouse brain were less dramatic. The order of the acyl-CoA synthetase activities for fatty acids of different chain lengths was palmitic acid>arachidonic acid>docosahexaenoic acid>octanoic acid. The analytical method proved to be very useful for the analysis of the acyl-CoA profile of tissues. Our results have important implications for understanding the regulation of acyl-CoA synthetase activity and long-chain fatty acid turnover in the phospholipids in the brain.