Further Observations on the Red Pigments of Pellagra Urines

Abstract

Conclusions1. The color noted in positive Beckh-Ellinger-Spies tests is not due to porphyrin. While a marked increase in urinary porphyrin, such as occurs in porphyria, would be productive of color, the color reaction as observed in pellagra and other diseases, is due to urorosein, first described by Nencki and Sieber. There is no evidence that the color reaction is due to any bile pigment derivative. 2. The urines of pellagra patients may contain either the chromogen of urorosein, or a red pigment extracted by the toluene preservative. It appears highly probable that this pigment is indirubin, although exact identification has not yet been made. 3. Both of the red substances may be noted in the urines of patients not having clinical pellagra. Further investigation is necessary to decide whether their appearance is related to deficiency of nicotinic acid or other essential substances.