INDUCTION OF COENZYME-A-DEPENDENT TRANSACYLATION ACTIVITY IN RAT-LIVER MICROSOMES BY ADMINISTRATION OF CLOFIBRATE

The effect of administration of clofibrate on the activity of coenzyme A-dependent (CoA-dependent) transacylation of 1-acyl-glycerophosphoch oline (1-acyl-GPC) was examined in rat liver microsomes. Administratio n of clofibrate to rats increased the activity of CoA-dependent transa cylation of 1-[C-14]acyl-GPC and the activity reached a value (8.37 nm ol/min per mg protein) twice that in control rats (3.95 nmol/min per m g protein) without any changes in apparent K(m) values for CoA (1.2 mu M in control and 1.0 muM in clofibrate-treated) and 1-acyl-GPC (33.4 m uM in control and 27.8 muM in clofibrate-treated). The rate of CoA-dep endent transfer of [C-14]arachidonic acid (20:4) from 1-acyl-2-[C-14]2 0:4-glycerophosphoethanolamine (GPE) or 1-acyl-2-[C-14]20:4-glyceropho sphoinositol (GPI) to 1-acyl-GPC (synthesis of 1-acyl-2-[C-14]20:4-GPC ) was also increased by treatment with clofibrate (1.9-fold and 1.5-fo ld increases, respectively). These results suggest that a CoA-dependen t transacylation system of 1-acyl-GPC was induced by treatment with cl ofibrate.