Role of stearoyl-CoA desaturase in the modification of acyl composition of hepatic phosphatidylcholine by peroxisome proliferators.

The relative contribution of stearoyl-CoA desaturase and 1-acylglycerophosphocholine (1-acyl-GPC) acyltransferase, which are induced by peroxisome proliferators, to the increase in the proportion of oleic acid in C-2 position of phosphatidylcholine (PtdCho) in the liver of rats was investigated. Rats were administered either 4-chlorophenoxyisobutyric acid (clofibric acid), 2,2'-(decamethylenedithio)-di-ethanol (tiadenol) or perfluorooctanoic acid in varying doses. With administration of these peroxisome proliferators, the proportion of oleic acid in C-2 position of PtdCho in hepatic microsomes was increased in commensurate with the increase in activities of stearoyl-CoA desaturase and 1-acyl-GPC acyltransferase. Multiple regression analysis revealed that although there is a high correlation among the three parameters examined, the partial correlation between the proportion of oleic acid in the C-2 position and the activity of stearoyl-CoA desaturase is significantly higher than that between the proportion of oleic acid in the C-2 position and the activity of 1-acyl-GPC acyltransferase. The contribution of stearoyl-CoA desaturase to the increase in the proportion of oleic acid in the C-2 position thus appears greater than that of 1-acyl-GPC acyltransferase.