Effect of retinoic acid, butylated hydroxytoluene, selenium and sorbic acid on azo-dye hepatocarcinogenesis.

Groups of male Sprague-Dawley rats were maintained on a basal diet containing 0.05% 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) for 9 weeks. The diets of these groups were supplemented at certain stages of the study with retinoic acid, butylated hydroxytoluene (BHT), or sorbic acid. In other groups, selenium (as sodium selenite) was added to the drinking water. The study was terminated after 9 weeks and the livers evaluated for pre-cancerous changes and presence of tumors. 38/42 animals in the control groups given the diet containing the 3'-MeDAB developed liver tumors. Only 3/27 rats given the 3'-MeDAB regimen supplemented with retinoic acid had liver tumors. A similar reduction was obtained with BHT, while sorbic acid exerted no protective effect against hepatocarcinogenesis. Se supplementation afforded some protection if given throughout or during the early stages of azo-dye administration and a lesser effect if given during the later stages of dye feeding.