5-Methyltryptophan and Darkening of the Hair in Yellow A^y/a Mice

Abstract

PREVIOUS experiments have shown that powdered preparations of the skin and hair of yellow (A^y/a) mice oxidize L- (but not D-) tryptophan and also DL-5-hydroxytryptophan with the production of yellow solutions^1,2. To obtain further evidence on the question of whether tryptophan, or a derivative, might be implicated in the production of yellow pigment in the hairs of this strain of mice, in vivo experiments were carried out using an antimetabolite of tryptophan³. Starting at 3–4 days of age, daily subcutaneous injections of DL-5-methyltryptophan were made in these mice for a period of 7–10 days. This is a period of vigorous pigment production. (Mice were obtained from the R. B. Jackson Memorial Laboratories, Bar Harbor, Maine. DL-5-methyl-tryptophan was a product of Sigma Chemical Co., St. Louis, Mo.)