A NOVEL ALDEHYDE REDUCTASE WITH ACTIVITY TOWARDS A METABOLITE OF AFLATOXIN-B1 IS EXPRESSED IN RAT-LIVER DURING CARCINOGENESIS AND FOLLOWINGTHE ADMINISTRATION OF AN ANTIOXIDANT

In contrast with fractions from control animals, an aldehyde reductase , which catalyses the reduction of aflatoxin B1-dihydrodiol, in the di aldehyde form at physiological pH values, to aflatoxin B1-dialcohol, i s expressed in cytosolic fractions prepared from rat livers bearing pr e-neoplastic lesions, or following treatment with the anti-oxidant eth oxyquin. This expression parallels the development of resistance to th e toxin. Unlike the aflatoxin B1-dihydrodiol, the dialcohol does not u ndergo binding to protein. This enzyme activity could play a mechanist ic role in hepatocarcinogenesis and chemoprotection in the rat. Correl ated n.m.r. and m.s. spectra are provided in Supplementary Publication SUP 50171 (3 pages), which has been deposited at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Bioc hem. J. (1993) 289. 9.