The livers of intact male or female rats bearing a transplanted osteogenic sarcoma contain elevated levels of tryptophan pyrrolase and tyrosine transaminase. Five days after adrenalectomy the enzyme levels become identical to those in nontumor-bearing rats. The results indicate that tumor-bearing is associated with increased pituitary-adrenal activity and that the rise in enzymes (inducible by hydrocortisone) in the tumor-bearing rats is a consequence of increased adrenocortical secretion. The metabolic consequences of this nonspecific effect of tumor on the host are discussed.

The activity of arginine phosphokinase, an important muscle enzyme in insects, was investigated with age in vestigial-winged and wild-type Drosophila melanogaster. Identical patterns of age-dependent activity changes were observed in the vestigial-winged flies as in the wild-type, even though vestigial-winged flies exhibit a 50% mortality approximately two thirds that of the wild-type as well as being incapable of flight. Results indicate that the age-dependent changes in arginine phosphokinase activity are intrinsically regulated within the cells of the flight muscle.