Studies on the interrelated stimulation of microsomal omega-oxidation and peroxisomal beta-oxidation in rat liver with a partially hydrogenated fish oil diet.
To investigate the mechanism for initiation of peroxisomal beta-oxidation by high-fat diets the time-courses of peroxisomal beta-oxidation and microsomal omega-oxidation stimulated by 20% (w/w) partially hydrogenated fish oil were studied. The relative stimulation of these two activities developed in a very similar way. We also observed an elevated level of long-chain acyl-CoA with partially hydrogenated fish oil, but not of free fatty acids. There was, however, a significant shift in the composition of free fatty acids to a higher amount of monoenes and lower amounts of 18:2 and 20:4 fatty acids. In peroxisomes purified by Nycodenz gradient centrifugation there was no lauric acid hydroxylation. This study indicates that with partially hydrogenated fish oil we obtain a parallel stimulation of reactions in two different cellular compartments. Dicarboxylic fatty acids, which are products of the omega-oxidation, had only a slight stimulatory effect on peroxisomal beta-oxidation. Therefore, the primary stimulatory agent of peroxisomal beta-oxidation and microsomal omega-oxidation is still unknown. It was speculated that this agent may activate a gene-locus responsible for both reactions.
D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D002458:Cell Fractionation; D003998:Dicarboxylic Acids / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism*; D005395:Fish Oils / Q000494:pharmacology*; D007700:Kinetics; D008099:Liver / Q000648:ultrastructure*; D008297:Male; D008830:Microbodies / Q000187:drug effects / Q000378:metabolism*; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains
D000214:Acyl Coenzyme A; D003998:Dicarboxylic Acids; D004041:Dietary Fats; D005227:Fatty Acids; D005395:Fish Oils