Murine strain differences in ovotoxicity following intraovarian injection with benzo(a)pyrene, (+)-(7R,8S)-oxide, (-)-(7R,8R)-dihydrodiol, or (+)-(7R,8S)-diol-(9S,10R)-epoxide-2.

Murine ovarian tumors produced by polycyclic aromatic hydrocarbons like benzo(a)pyrene (BP) require small oocyte destruction. Small oocyte destruction was evaluated in C57BL/6N (B6), DBA/2N (D2), and C57BL/6J X DBA/ 2JF1 (B6D2F1) mice following intraovarian injection with BP, (+)-( 7R ,8S)-oxide, (-)-( 7R , 8R )-dihydrodiol [(-)-DHD], or (+)-( 7R ,8S)-diol-(9S, 10R )-epoxide-2 [(+)- DE2 ] at doses ranging from 0.01 to 30 micrograms/ovary. BP, (-)-DHD, and (+)- DE2 produced small oocyte destruction in a dose-dependent fashion. The (+)-( 7R ,8S)-oxide did not destroy small oocytes at the highest dose tested (10 micrograms/ovary). The rank orders of the calculated doses which resulted in the destruction of 50% of the small oocytes (ED50S) for small oocyte destruction were BP approximately equal to (-)-DHD greater than (+)- DE2 in all three groups of mice. However, the ED50S for BP and (-)-DHD differed considerably among B6, D2, B6D2F1 mice; ED50S were smallest in B6 mice and largest in D2 mice. The ED50S for oocyte destruction in B6D2F1 mice were intermediate or similar to ED50S for B6 mice, depending on the method used for calculation. In spite of large strain differences in ED50S for BP and (-)-DHD, the ED50S for (+)- DE2 were similar in B6, D2, and B6D2F1 mice. The similar ED50 for (+)- DE2 suggests that it is an ultimate ovotoxin and ovarian carcinogen and that the target molecule(s) and mechanism(s) of detoxification are similar in B6, D2, and B6D2F1 mice.