The role of different fatty acids in the regulation of mitochondrial respiration in situ

Abstract

The role of fatty acids (both saturated and unsaturated and of various chain length) in the regulation of mitochondrial respiration in situ using saponinpermeabilized rat cardiac fibers was investigated. We have found that the oxidation of both saturated nonactivated fatty acid decanoate and unsaturated fatty acid ester oleoyl-CoA induces a marked (3–4-fold) decrease in app. Km for ADP, if compared to pyruvate + malate oxidation. In conclusion, our present and previous data show that different fatty acids (saturated and unsaturated, activated or not, long and medium chain) similarly decrease app. Km ADP. Based on these findings and the similarity of effects obtained previously with saturated fatty acids, we conclude that this property is common to all fatty acids. Keywords: saponin-permeabilized heart muscle fibers, outer mitochondrial membrane permeability, fatty acid oxidation; oxidative phosphorylation