title: The effect of intraovarian injection of benzo(a)pyrene on primordial oocyte number and ovarian aryl hydrocarbon [benzo(a)pyrene] hydroxylase activity.
abstract: The effect of intraovarian (io) injection of benzo(a)pyrene (BP) on primordial oocyte number, ovarian aryl hydrocarbon hydroxylase (AHH, EC 1.14.14.1) activity, and hepatic AHH activity and P-450 content was investigated in C57BL/6N (B6) and DBA/2N (D2) mice. Ovaries were exteriorized through dorsolumbar incisions under ether anesthesia, and 1.0 microliters of corn oil or corn oil containing BP was injected directly into the ovary. Bilateral io injection of BP was ovotoxic in a time and dose dependent manner. Primordial oocyte destruction was maximal 8 days after injection in both B6 and D2 mice. Unilateral io injection of BP destroyed oocytes only in the treated ovary. The threshold dose for primordial oocyte destruction was similar in both strains, approximately 50 ng/ovary. However, ED50's were different; 1.1 micrograms/ovary in B6 and 8.9 micrograms/ovary in D2 mice. Intraperitoneal treatment with alpha-naphthoflavone (80 mg/kg) inhibited the oocyte destruction by io treatment with BP (10 micrograms/ovary) in both B6 and D2 mice. In B6 mice, ovarian AHH activity was induced by BP in the treated ovary after either bilateral, or unilateral io treatment. However, io BP treatment did not change ovarian AHH activity in D2 mice. Hepatic AHH activity and P-450 content was not altered by io BP treatment in either mouse strain. These results strengthen the hypothesis that the ovary has the capability of metabolizing BP to ovotoxic products.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D001564:Benzo(a)pyrene / Q000494:pharmacology*; D001571:Benzoflavones / Q000494:pharmacology; D002452:Cell Count; D004305:Dose-Response Relationship, Drug; D005260:Female; D007267:Injections; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009865:Oocytes / Q000187:drug effects*; D010053:Ovary / Q000187:drug effects*
chemical_list: D001571:Benzoflavones; D001564:Benzo(a)pyrene; C011512:alpha-naphthoflavone; D001189:Aryl Hydrocarbon Hydroxylases