Adverse effects of dibutyltin dichloride on initiation and maintenance of rat pregnancy

The present study was conducted to evaluate the adverse effects of dibutylt in dichloride (DBTCl) on initiation and maintenance of pregnancy after mate rnal exposure during early pregnancy in rats. After successful mating, fema le rats were given DBTCl by gastric intubation on Days 0 to 3 or on Days 4 to 7 of pregnancy at 0, 3.8, 7.6, or 15.2 mg/kg. Food-restricted pregnant r ats were given an amount of feed equal to the feed intake of female rats tr eated with DBTCl at 15.2 mg/kg on Days 0 to 3 or on Days 4 to 7 of pregnanc y. Female rats were sacrificed on Day 20 of pregnancy and pregnancy outcome was determined. After administration of DBTCl on Days 0 to 3, the rate of nonpregnant females and the incidence of preimplantation embryonic loss in the 7.6 mg/kg group were significantly higher than those in the control gro up, and those in the 15.2 mg/kg group were significantly higher than those in the control and pair-fed groups. In females with implantations, the numb ers of implantations and live fetuses and the incidence of postimplantation embryonic loss in the groups given DBTCl on Days 0 to 3 were not significa ntly different from those in the control group. The incidence of postimplan tation embryonic loss in the groups given DBTCl on Days 4 to 7 at 7.6 and 1 5.2 mg/kg was significantly higher than that in the control and pair-fed gr oups. It can be concluded that DBTCl adversely affects initiation and maint enance of pregnancy when administered during early pregnancy and that the m anifestations of the adverse effects of DBTCl vary with the gestational sta ge at the time of maternal exposure. (C) 2000 Elsevier Science Inc. All rig hts reserved.