[Effect of thyroxine on the energy processes of liver and heart tissue in embryogenesis]

The influence of various amounts (0.008; 0.0025; 0.25 microgram per 1 g of body weight of the embryo) of thyroxin on the energy processes of the embryonic tissue was studied. On the 10th, 13th, and 16th days of the embryonic development low and medium doses of thyroxin failed to alter the rate of respiration and of phosphorylation in the liver homogenates. An increase of the oxygen consumption intensity without the change of the respiratory control (RC), P/O in the succinate oxidation occurred in the heart tissue. On the 19th day thyroxin uncoupled the oxidative phosphorylation in the glutamate oxidation. High hormone doses decreased the rate of respiration, RC in the liver at all the embryogenesis stages, and failed to influence the heart.