Effect of Endurance Training on the Capacity of Red and White Skeletal Muscle of Mouse to Oxidize Carboxyl-14C-labelled Palmitate

Abstract

Groups (3) of mice were trained for 1, 4 and 5 mo. according to different running programs on a motor driven treadmill and the fatty acid oxidation capacity (FAO) and the activities of some enzymes of energy metabolism (cytochrome c oxidase, malate dehydrogenase, triosephosphate dehydrogenase and lactate dehydrogenase) were determined from quadriceps femoris muscle (MQF). Endurance training increased the FAO [5 mo. training, 4 days/wk, 30 min/day 22% (P < 0.05); 1 mo. training, 7 days/wk, 150 min/day 37% (P < 0.001); 4 mo. training, 5 days/wk, 60 min/day 24% (P < 0.05)]. The activities of cytochrome c oxidase and malate dehydrogenase increased approximately 30% (P < 0.001) whereas triosephosphate dehydrogenase and lactate dehydrogenase activities were not prominently influenced by training. The predominantly red part of MQF of untrained animals oxidized palmitate 4 times faster than the predominantly white part. The activities of cytochrome c oxidase and malate dehydrogenase were 2 times higher showing pronounced FAO in the red part. Endurance training increased the FAO and activities of oxidative enzymes in the red and white parts and in the whole muscle relatively equally resulting in similar differences between the muscle types after training. The absolute increase in the FAO of the red muscle was manyfold when compared in chemical units to the white muscle.