PARENT SESSION
1D Bioassays for specific hazards (estrogenic effects, genotoxicity, neurotoxicity, ...)
9:00 AM to 7:00 PM, Tuesday, 08 May 2001

(T/EH061) Alteration of the behavioral effects of sex steroids in rats after developmental PCB exposure.

Kaya, Hatice¹, Lilienthal, Hellmuth¹, Hany, Juergen¹, Fastabend, Annemarie¹, Roth-Haerer, Astrid¹, Winneke, Gerhard¹, ¹

ABSTRACT- Our previous results indicated an influence on sexual differentiation of the brain in male rat pups exposed to a PCB-mixture which was reconstituted according to the congeners found in human milk. The present presentation reports alterations of the behavioral effects of sex steroids in adult male offspring after dietary exposure of dams to the reconstituted mixture at doses of 0, 5, 20, or 40 mg/kg diet, resulting in an average daily intake of 0, 0.5, 2, or 4 mg/kg body wt. An additional group of rats received maternal treatment with single PCB congeners, PCB47 and PCB77, alone or in combination. Dams of this part were injected s.c. with 1.5 mg/kg PCB47, 1.5 mg/kg PCB77 or with a combination of 1.0 mg PCB47 + 0.5 mg PCB77/kg daily from gestational day 7-18. Male offspring of the PCB77- and the combined group exhibited less aversion against a saccharin solution when examined for conditioned taste aversion with estradiol (10 g/kg). In testosterone-conditioned place preference (70 g/kg), the reconstituted PCB mixture resulted in a preference for the testosterone-paired side at the highest exposure condition. Furthermore, a dose-dependent elevation of sweet preference was found in adult male offspring, indicating feminization of this sexually dimorphic behavior. In weanling female offspring, dose-dependent reductions of serum testosterone and estradiol levels were detected. Testosterone concentrations were reduced in a dose-dependent manner in adult male littermates. These results indicate long-lasting and dose-dependent changes in the behavioral effects of sex steroids and sexually dimorphic behavior together with reduced levels of sex steroids after developmental exposure to PCBs. (grants PUG 95003 and 97004, State of Baden-Wuerttemberg, Germany, to H.L.).

Key words: sex steroids, sexual differentiation, behavior, polychlorinated biphenyls