Reproductive tract defects induced in adult male rats by postnatal 1,2-dibromo-3-chloropropane exposure.

The reproductive tract of the male rat may be particularly susceptible to chemical injury during the early postnatal period since significant developmental changes occur in the tract at that time. The subcutaneous administration of relatively low doses of 1,2-dibromo-3-chloropropane (DBCP, 5-20 mg/kg) on alternate days, from 2 to 20 days of life, resulted in a marked dose-related reduction in the testis, epididymis, and seminal vesicle weights. Histological evaluation revealed degenerative cellular changes in the testes of the 5 mg/kg treated group and obliteration of the seminiferous tubules in the 10 mg/kg treated animals. Biochemical studies showed that the in vitro androgen production capacity per unit weight of testicular tissue was elevated, as a function of the DBCP dose, correlating with the apparent increases in the Leydig cell concentrations observed histologically in the treated animals. Due to the marked reduction in the testes weight of DBCP-treated animals, the in vitro testicular androgen production rate, when expressed on the basis of testes pair weight, was reduced; it was consistent with the observed DBCP-induced decrease in serum androgen levels. Early DBCP exposure also obliterated the androgen responsiveness of the seminal vesicle and epididymis in the adult rat, which may also contribute to the diminution in the weights of these androgen-dependent organs. The present study also indicated that immature rats were more susceptible than sexually matured male rats to DBCP toxicity. Moreover, the results of the critical period study indicated that the first 10 days of life are of particular importance in the reproductive tract toxicity of DBCP.