The effect of adrenalectomy and of cortisone administration on the metabolism of L-tryptophan.

Paper chromatography has provided an excellent method for the detection and identification of tryptophan and its fluorescing metabolites (1) and has proved helpful in the development of methods for the quantitative calorimetric estimation of tryptophan, kynurenine, and anthranilic acid (2). The purpose of this communication is to report the use of these techniques in determining the effect of adrenalectomy and cortisone administration upon the metabolism of n-tryptophan in the rat, as judged from urinalysis after feeding n-tryptophan and from the metabolism of n-tryptophan and n-kynurenine by liver and kidney slices. According to Porter, Stoerk, and Silber (3), adrenalectomy decreases the kynurenic acid output in the rat fed tryptophan, but does not alter the output of kynurenine and of xanthurenic acid. The administration of cortisone acetate to the adrenalectomized rat restores the kynurenic acid excretion to normal but does not affect the output of kynurenine and of xanthurenic acid. They therefore assumed that the effect of the hormone was to increase the rate of deamination or transamination whereby kynurenine was converted to kynurenic acid. In tests involving the use of liver homogenates from normal and adrenalectomized rats, Knox observed that the production of kynurenine from DLtryptophan was smaller with the latter animals (4). Subsequently, Knox and Auerbach reported that they were unable to find any other product of n-tryptophan oxidation besides kynurenine by methods which should have indicated the presence of anthranilic or kynurenic acid (5). Previous observations from our laboratory had indicated that both of these metabolites and kynurenine were formed by normal liver homogenates (2) and by normal liver slices (1) under conditions apparently similar to those used by Knox and Auerbach (5).