[Reactions of energy supply and thermogenesis in the tissues of animals born mature and immature].

In the heart and skeletal muscle homogenates of mature-born neonate and adult guinea pigs succinate is oxidized intensively with a low phosphorylation rate and NAD . H without ADP phosphorylation; both the substrates are oxidized without phosphorylation in the brown fat. In the heart homogenate of immature-born neonate rats succinate is oxidized with a high ADP phosphorylation; in the skeletal muscle homogenate these substrates are oxidized with a low rate and in the brown fat homogenate with a high rate and without ADP phosphorylation. The liver homogenate of all animals in characterized by succinate phosphorylating oxidation and low rate of NAD . H oxidation. These data suggest that in homothermic animals a number of tissues have, besides the phosphorylating, also the non-phosphorylating (uncoupled-oxidizing) respiration system which might be directly related to the provision for the organism's homothermic state.