Abnormal tryptophan metabolism in a family with a history of bladder cancer.

Abstract

Tryptophan metabolism was studied in a family in which a sister and brother had bladder cancer. Urinary tryptophan metabolites after administration of 2 g L-tryptophan were measured in 4 sisters and 1 brother, all free of disease when studied. One sister with and 2 without histories of bladder cancer had significantly elevated levels of kynurenine, acetylkynurenine, and 3-hydroxykynurenine. Administration of 100 mg pyridoxine hydrochloride returned the tryptophan metabolism to normal in these 3 individuals. One brother with a 1 sister without bladder cancer had normal metabolism. A repeat study 2 years later confirmed the abnormal metabolism in the 3 sisters. Two sisters with abnormal tryptophan metabolism were given 200 mg L-kynurenine sulfate orally to bypass the effects of tryptophan oxygenase activity. Both excreted elevated levels of kynurenine and 1 excreted elevated levels of 3-hydroxykynurenine.