Depressions by dietary phospholipids of soybean and egg yolk origins of hepatic triacylglycerol and fatty acid synthesis in fasted-refed rats.

Effects of various phospholipid preparations from soybean and egg yolk origins on various indices for lipid biosynthesis in the liver were compared in fasted-refed rats. Phospholipid preparations employed were soybean phospholipid mainly consisting of phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidic acid (soybean PL), egg phospholipid mainly consisting of phosphatidylcholine and phosphatidylethanolamine (egg PL) and purified phosphatidylcholines from soybean (soybean PC) and egg yolk (egg PC) origins. The diet containing 3% fatty acids as soybean and egg PLs compared to the those containing the same amount of fatty acids as the fat blend simulating fatty acid composition of soybean PL and no fatty acids profoundly decreased hepatic concentration of triacylglycerol and liver microsomal concentration of diacylglycerol. Soybean and egg PCs compared to the fat blend also decreased the concentrations of these lipid components in the liver but with the much less extents. Soybean and egg PLs compared to the fat blend also profoundly decreased the activities of enzymes in fatty acid synthesis and of microsomal glycerol 3-phosphate acyltransferase in the liver. These phospholipid preparations compared to the fat blend also significantly decreased the activity of microsomal diacylglycerol acyltransferase when it was measured with endogenous microsomal diacylglycerol substrate. The purified PCs from soybean and egg yolk origins compared to the fat blend also significantly decreased some of these parameters in lipid biosynthesis in the liver but with the much less extents.(ABSTRACT TRUNCATED AT 250 WORDS)