Influence of fatty acids on microsomal diacylglycerol acyltransferase activity in primary cultures of hepatocytes.
The regulation of triacylglycerol synthesis by various long-chain fatty acids was studied using primary cultures of hepatocytes. The activity of diacylglycerol acyltransferase was measured after 72-h incubation with various fatty acids in equimolar concentrations (0.5 mM): oleate, linoleate, linolenate, palmitate, stearate and arachidonate increased enzyme activity to 191%, 161%, 148%, 124%, 116% and 114%, respectively, compared to controls. Cellular triacylglycerol levels showed the same changes, suggesting a regulatory function of diacylglycerol acyltransferase in triacylglycerol synthesis. Elaidate lowered the enzyme activity by 57%. The addition of different fatty acids to the incubation medium did not influence the distribution of enzyme activity in the 30 000 x g pellet which was routinely discarded and the microsomal fraction (105 000 x g), where the enzyme was predominantly localized (91%). The release of lactate dehydrogenase into the culture medium of hepatocyte monolayers as well as ketone body production was not affected by any of the fatty acids.
D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D051048:Diacylglycerol O-Acyltransferase; D005227:Fatty Acids / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D005227:Fatty Acids; D007770:L-Lactate Dehydrogenase; D000217:Acyltransferases; D051048:Diacylglycerol O-Acyltransferase