The Effect of Octanoate and Palmitate on the Metabolism of Valine in Perfused Hindquarter of Rat

Abstract

The effect of octanoate and plamitate on the oxidation of 14C-labeled valine was studied in perfused hindquarter of rat. The oxidation rate of valine increases 30 times when the concentration of valine is increased from 0.1 to 5 mM. Octanoate at a 5 mM concentration effected a 10-fold increase in the flux through the .alpha.-keto-isovalerate dehydrogenase step and a 5-fold increase of 0.5 mM concentration. Palmitate (1 mM) effects only a moderate increase in the valine oxidation. With no octanoate there was a great accumulation of .alpha.-ketoisovalerate in both the muscle and the perfusion medium. With octanoate little .alpha.-ketoisovalerate accumulated whereas 3-hydroxyisobutyrate was found in high concentration both in the muscle and in the medium. Octanoate stimulated the production of citric-acid-cycle intermediates and lactate. The results are discussed in relation to valine metabolism in the body.