COMPARATIVE TERATOLOGICAL STUDIES ON TCDD, ENDRIN AND LINDANE IN C57BL 6J AND DBA/2J MICE/

The teratogenic effects of endrin and lindane have been determined and compared to those induced by TCDD in the fetuses of C57BL/6J and DBA/ 2J mice after the administration of single oral doses to pregnant mice on day 12 of gestation. TCDD produced dose-dependent decreases in fet al weight, fetal thymic weight and placental weight, and dose-dependen t increases in fetolethality, cleft palate formation and hydro-nephros is at doses of 10-30 and 30-60 mu g/kg body weight in C57BL/6J and DBA /2J mice, respectively. No maternal death was observed at the given do ses in both strains of mice. Endrin (4.5 and 6 mg/kg body weight) and lindane (30 and 45 mg/kg body weight) produced significant decreases i n fetal weight and placental weight in C57BL/6J and DBA/2J mice, and d ose-dependent decreases in fetal thymic weight in C57BL/6J mice but no t DBA/2J mice. Endrin and lindane caused 0-25 and 14-25% maternal deat hs, respectively, at the above mentioned doses. Neither cleft plate no r hydronephrosis were induced by endrin or lindane in the two strains of mice. The results support the hypothesis that TCDD-induced cleft pl ate and hydronephrosis involve mechanisms that are Ah (aryl hydrocarbo n) receptor mediated. However, other fetotoxic effects induced by TCDD , and the fetotoxic effects induced by endrin and lindane may involve additional unknown mechanisms that are not related to the Ah-receptor.