[Quantitative evaluation of the mutagenic potential of benzo(a)pyrene by in vitro and in vivo tests].

The study was concerned with benzo(a)pyrene (BP) mutagenicity tests involving induction of direct genetic mutations in hypoxanthin-guanine phosphoribosyl transferase (HGPRT) loci in Chinese hamster cells V-79. Tests were carried out under the conditions of metabolic activation by mouse liver microsome enzymes. Micronuclei in polychromophilic erythrocytes of mouse bone marrow were counted. The number of genetic mutations induced by a mean toxic dose (TD50) of BP was 10 times the level of spontaneous mutations in cultured cells. Micronuclei in mouse polychromophilic erythrocytes were twice the number in controls following BP treatment in a dose amounting to one-third of the least lethal doses reported so far. In vitro and in vivo evaluation of BP mutagenicity was carried out in V-79/HGPRT system after Wood et al (1976).