The effect of fatty acid exposure on the biosynthesis of glycerolipids by cultured hepatocytes.
Incubation of hepatocyte monolayers with oleate or palmitate (1.0 mM) for 2-48 h, increased (20 to 80%) the incorporation of [1,3-14C]glycerol and palmitate into triacyglycerol but not phosphatidylcholine. The effect of fatty acids on liver cell triacylglycerol formation correlated well (r = 0.990) with a simultaneous rise (2-4-fold) in phosphatidate phosphatase (EC 3.1.3.4) activity. Phosphatidate phosphatase activity and triacylglycerol biosynthesis are also increased (2-fold) after hepatocyte monolayers are incubated for 24 h with cyclic GMP in the absence of fatty acids. Fatty acid-dependent increases in liver cell triacylglycerol formation and phosphatidate phosphatase activity are not blocked by cycloheximide. Phosphatidylcholine biosynthesis was also elevated in homogenates of liver cells exposed (24-48 h) to 1.0 mM oleate when exogenous CDPcholine was added to the incubation mixture. Apparently, the phosphatidate phosphatase-dependent rise in diacylglycerols that occurs after fatty acid exposure is primarily shunted into triacylglycerols because liver cell CDPcholine content is not correspondingly increased, and high levels of diacylglycerol acyltransferase (EC 2.3.1.20) and fatty acyl-CoA derivatives are present.
D000818:Animals; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D005227:Fatty Acids / Q000378:metabolism* / Q000494:pharmacology; D008099:Liver / Q000378:metabolism*; D008297:Male; D010713:Phosphatidylcholines / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000096:biosynthesis*
D005227:Fatty Acids; D010713:Phosphatidylcholines; D014280:Triglycerides