The Effects of Injected Biotin and Dethiobiotin on Butter Yellow Carcinogenesis in Rats Fed a Protective Diet

Abstract

Following the discovery of the carcinogenicity of the azo dye butter yellow (N,N-dimethyl-p-aminoazobenzene), a number of investigators (Nakahara, Mori, and Fujiwara 1938a, 1938b) established that feeding yeast or liver extracts to rats afforded them considerable protection against tumor formation by the dye. Working with purified diets, two further groups (Gyorgy, Poling, and Goldblatt 1941; Kensler et al. 1941) demonstrated that excess casein and riboflavin together were also highly protective against the action of the dye. However, du Vigneaud et al. (1942) have reported that the daily addition of 2 p,g of crystalline biotin to such a diet destroys its protection. This finding was confirmed in more extensive experiments by Burk et al. (1943), though Kline, Miller, and Rusch (1945) demonstrated that the dietary casein could be replaced by egg white and injections of 6 p,g of biotin weekly without affecting the protection.