Vitamin a status and metabolism of benzo[α]pyrene in the rat

Male Sprague‐Dawley rats were maintained on a vitamin A‐deficient diet for a period of five weeks. At the end of that time, hepatic cytochrome P₄₅₀ levels in vitamin A‐deficient rats were 65% that of rats fed a complete diet. However, the hepatic rate of benzoa]pyrene metabolism was significantly greater (2 times) in vitamin A‐deficient rats compared with those fed a complete diet. The pattern of metabolites separable by thin‐layer chromatography was similar in both groups of rats. Benzoa]pyrene induced its own metabolism by a slightly greater amount in the vitamin‐sufficient rats, but it was not to the level of the deficient group, although the levels of cytochrome P₄₅₀ were still below those of the deficient rats. In discussing lung microsomes, benzoa]pyrene pre‐treatment of deficient rats resulted in slightly elevated levels of cytochrome P₄₅₀ and a slightly greater rate of metabolism of benzoa]pyrene compared with rats fed the complete diet.