THE EFFECTS OF THYROXINE AND CERTAIN METAL IONS UPON OXIDATION AND PHOSPHORYLATIONIN VITRO1

Abstract
Studies on the effects of thyroxine on respiration and oxidative phosphorylation in a rat heart homogenate system were extended. Thyroxine accelerated O2 uptake and uncoupled oxidative phosphorylation. Mg inhibited the uncoupling effect of thyroxine while calcium exerted an action similar to that of thyroxine. Mg did not restore phosphorylating ability in the presence of thyroxine and Ca. Other cations[long dash]Mn, Co, Sr and Be[long dash]had less marked effects on respiration and phosphorylation.