BODY ORGAN CYTOCHROME OXIDASE ACTIVITY IN COLD- AND WARM-ACCLIMATED RATS

Publisher Website
Google Scholar
Abstract
The cytochrome oxidase activity was estimated in homogenates of the whole body and in nine body organs of cold- and warm-acclimated rats. The total body cytochrome oxidase activity expressed in terms of oxygen consumption was similar in cold- and warm-acclimated rats. In cold-acclimated animals the total cytochrome oxidase activity did not differ from maximal steady state metabolism measured in vivo, while in warm-acclimated rats the total cytochrome oxidase activity was almost twice as great as the maximal steady state metabolism. The results indicate that warm-acclimated rats do not utilize the full capacity of the cytochrome system and that cold-acclimation makes full exploitation of the oxidase capacity possible. In cold-acclimated rats the cytochrome oxidase activity of the muscles comprised 57% of the total, the liver 22.5%, and the skin 6%, with smaller roles for other organs. The role of the liver was greater in cold-acclimated than in warm-acclimated rats.