Metabolism of trans fatty acids by hepatocytes.
The present work was undertaken to study the metabolism of fatty acids with trans double bonds by rat hepatocytes. In liver mitochondria, elaidoyl-CoA was a poorer substrate for carnitine palmitoyltransferase I (CPT-I) than oleoyl-CoA. Likewise, incubation of hepatocytes with oleic acid produced a more pronounced stimulation of CPT-I than incubation with trans fatty acids. This was not due to a differential effect of cis and trans fatty acids on acetyl-CoA carboxylase (ACC) activity and malonyl-CoA levels. Elaidic acid was metabolized by hepatocytes at a higher rate than oleic acid. Surprisingly, compared to oleic acid, elaidic acid was a better substrate for mitochondrial and, especially, peroxisomal oxidation, but a poorer substrate for cellular and very low density lipoprotein triacylglycerol synthesis. Results thus show that trans fatty acids are preferentially oxidized by hepatic peroxisomes, and that the ACC/malonyl-CoA/CPT-I system for coordinate control of fatty acid metabolism is not responsible for the distinct hepatic utilization of cis and trans fatty acids.
Guzmán
M
M
Department of Biochemistry and Molecular Biology I, School of Biology, Complutense University, Madrid, Spain.
Klein
W
W
Gómez del Pulgar
T
T
Geelen
M J
MJ
D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar
D005227:Fatty Acids; D002334:Carnitine O-Palmitoyltransferase; D000103:Acetyl-CoA Carboxylase