Effect of exercise on the metabolism of fatty acids in the dog

Abstract

Dogs with indwelling arterial and venous catheters worked on a treadmill for 25–30 min. Exercise decreased the plasma free fatty acid (FFA) concentration and increased the blood glucose. In the postexercise period, the plasma inorganic P showed a significant decrease. Experiments with C14-palmitate and C14-oleate showed that the decrease of the plasma FFA was due partly to an elevated uptake and partly to a reduced rate of release into the blood. Infusions of Na lactate to resting dogs induced a marked increase in specific activity of plasma FFA, due to an inhibition of release. In spite of the reduced rate of release of FFA, the oxidation of the C14-fatty acid was considerably increased during exercise (three- to fourfold). No direct relationship seems to exist between the turnover rate of plasma FFA and the rate of oxidation of fatty acids.