Metabolic action of cortisone; D-amino acid oxidase and apparent creatinine formation

Data are presented demonstrating that the d-amino acid oxidase of rat liver is lowered on adrenalectomy and restored to normal by treatment with cortisone. This reaction is responsible for data obtained which indicated that creatine and creatinine formation were under the control of cortisone. The α-keto-γ-methiolbutyric acid formed from the oxidation of methione reacts in the Jaffe reaction as “creatinine.” During the course of incubation of the liver enzyme system a portion of the α-keto-γ-methiolbutyric acid appears in a bound form and is measured by way of the Jaffe reaction as “creatine.” Measurements of creatine formation by a method not subject to these errors show that creatine formation in the rat liver enzyme is very small although creatine formation in guinea pig liver can readily be demonstrated.