[Effect of thioacetamide on the incorporation of 32P into phospholipids of rat liver].

The effect of thioacetamide on rat liver phospholipids biosynthesis was investigated using 32P as precursor. The incorporation of 32P-ortophosphate in the polar lipid fraction and the specific radioactivities of individual phospholipids in the liver fraction and the specific radioactivities of individual phospholipids in the liver of control rats and rats treated with thioacetamide were determined 75 min after intraperitoneal administration of 32P-ortophosphate. Intraperitoneal injection of thioacetamide (daily dose of 100 mg/kg body weight) in male Wistar rats resulted in an increase of 32P incorporation in the over-all phospholipids, after 8 doses administration and a significant decrease during the chronic intoxication. Specific activity of phosphatidylcholine decreased and a parellel increase in specific radioactivity of lisophosphatidylcholine was found after three days of thioacetamide treatment. There was also observed a marked increase in specific radioactivity of sphingomyelin, which could be due to a stimulation of CDP-choline: ceramide cholinephosphotransferase reaction with subsequent diminution of the rate of phosphatidylcholine synthesis via the CDP-amine pathway (involving cytidine diphosphocholine).