Changes in Succinic Dehydrogenase Activity and Fatty Acid Composition of Rat Liver Mitochondria in Essential Fatty Acid Deficiency

Abstract

The effects of feeding diets containing corn oil, coconut oil, tuna oil, or no fat on the sequence of development of growth inhibition and altered mitochondrial fatty acid compositions and succinic dehydrogenase activities were studied. The mitochondrial succinic dehydrogenase activities of rats fed tuna oil were higher than those of the control (corn oil) rats, but lower than those of the other EFA-deficient rats throughout the experiment. Suggestive differences between control and deficient mitochondria were noted after one week of the experiment and were marked after 2 weeks. The exposure to water, the addition of calcium ion, or the addition of snake venom elevated the mitochondrial succinic dehydrogenase activities, and eliminated or reduced the differences between the control and EFA-deficient rats. The appearance of eicosatrienoic acid and a reduction of arachidonic and linoleic acids in mitochondrial lipids from the fat-free and coconut oil groups occurred within one week after initiating the experiment. The feeding of tuna oil resulted in significant amounts of a highly polyunsaturated fatty acid of calculated carbon number 23.4, which was, perhaps, eicosapentaenoic acid, but not of eicosatrienoic acid in mitochondrial lipid. The alterations of mitochondrial fatty acid composition in EFA deficiency preceded slightly the appearance of elevated succinic dehydrogenase activity.