Alterations in phospholipid biosynthesis by polychlorinated biphenyls and polychlorinated biphenylols

Inhibition and stimulation of synthesis of phospholipids by polychlorinated biphenyls (PCB) have been reported by several authors. The mode of action of PCB on the synthesis of phospholipids has not been determined. Results of experiments in the present report indicate that both PCB and polychlorinated biphenylols alter the activities of key enzymes of glyceride and phospholipid synthesis. 4-Chloro-4-biphenylol (CB-OH), 2',3',4',5,5'-pentachlorobiphenylol (PCB-OH) and 2,4,5,2',4',5'-hexachlorobiphenyl (HCB) inhibited sn-glycerol-3-phosphate acyltransferase activity. Inhibition by PCB-OH was noncompetitive with apparent Ki of 2.6 X 10(-4) M. PCB-OH stimulated phosphatidase activity, but no apparent change was observed with CB-OH. PCB inhibited phosphorylcholine glyceride transferase activity, but had no significant effect on diglyceride acyl transferase.