Effects of diethanolamine on phosphatidylcholine biosynthetic enzymes of rat liver microsomes

Abstract 1. 1. The effect of administration of diethanolamine on the phosphatidylcholine biosynthetic enzymes. phosphatidylethanolamine methyltransferase, phosphatidyldimethylethanolamine methyltransferase and choline phosphotransferase of liver microsomes was measured in rats. 2. 2. In animals fed a stock diet for 3 days plus 0.5 mmol of diethanolamine by intraperitoneal injection. a significant stimulation of the activity of phosphatidylethanolamine methyltransferase was observed. There was a significant inhibition of choline phosphotransferase. 3. 3. Rats stomach tubed with 1 mmol diethanolamine for 3 days showed a significant stimulation of phosphatidylethanolamine methyltransferase and phosphatidyldimethylethanolamine methyltransferase activities. There was a significant inhibition of choline phosphotransferase. 4. 4. A cholinemethionine deficient diet was used to facilitate the incorporation of diethanolamine into an atypical phospholipid fraction. Feeding this diet containing 1% diethanolamine for 7 days resulted in a significant decrease in the in vitro activity of the methylating enzymes phosphatidylethanolamine methyltransferase, phosphatidylmonomethylethanolamine methyltransferase and phosphatidyldimethylethanolamine methyltransferase.