Cytochrome Oxidase Activity and Body Weight in Rats and in Three Species of Large Animals

Abstract

Study of the relationship of cytochrome oxidase activity of certain tissues to the body weight has been extended to include three species of large animals. In the comparison of rats, sheep, swine and cattle, the cytochrome oxidase activity of skeletal muscle (principally of the gracilis) was found to be roughly an inverse function of body weight. A logarithmic regression of –0.239 was calculated. Although the cytochrome oxidase activity per unit weight of liver in the sheep, swine and cattle series does not reflect the variation in body mass, the regression of the logarithm of total liver cytochrome oxidase activity on the logarithm of body weight was calculated to be 0.674. The data support the concept that the summated total measurable cytochrome oxidase activity is very nearly proportional to body weight to the 3/4 power and, hence, to basal metabolism.