TRIACYLGLYCEROL AND FATTY-ACID SYNTHESIS IN HEPATOCYTES IN SUSPENSION ISOLATED FROM RATS FED SOYBEAN PHOSPHOLIPID

The rates of triacylglycerol and fatty acid synthesis in hepatocytes in suspension isolated from rats fed dietary soybean phospholipid were compared with those from the animals fed soybean oil. The rats were fed the experimental diets containing either soybean phospholipid or soybean oil (the dietary levels correspond to 3% fatty acids, 5.1 and 3.2% on weight bases for the phospholipid and the oil, respectively) for 10 days. Dietary soybean phospholipid compared to the oil decreased the rate of incorporation of [2-H-3]glycerol into triacylglycerol in isolated hepatocytes. However, the difference disappeared when the incubation mixture was fortified with oleate substrate (1 mM). The dietary phospholipid compared to the oil greatly decreased the rate of incorporation of [1-C-14]acetate into fatty acids while it increased that of the tracer into cholesterol. The rate of ketone body production from oleate substrate was decreased in rats fed soybean phospholipid compared to those fed the oil. Thus, dietary soybean phospholipid compared to soybean oil appears to reduced the availability of fatty acids for triacylglycerol synthesis in rat liver through the depression in the rate of fatty acid synthesis.