Comparative study on placental transfer and maternal distribution of organic and inorganic tin following oral administration in pregnant rats

Placental transfer and body distribution of triphenyl tin chloride (TPTC) and tin chloride (SnCl₂) were investigated in pregnant rats. Pregnant Wistar rats were orally administered TPTC at 0, 1.0 and 2.0 mg/rat/day during 6 ~ 10 and 14 ~ 18 days of gestation, and with SnCl₂ at 0 and 20 mg/rat/day on 7, 10 and 15 days of gestation (group treated 3 times) or 6 ~ 10 and 13 ~ 16 days of gestation at 0 and 20 mg/rat/day (group treated 9 times). On day 20 of gestation in rats treated with TPTC, and day 17 in rats with SnCl₂, fetuses, placentas, maternal blood and organs were obtained for analyses. Mean fetal tin levels from rats treated with 1.0 and 2.0 mg TPTC were 0.05 and 0.11 μg/g wet weight, respectively, these values being significantly (P < 0.01) higher than in the control group. The latter was higher than the former at a significance level of 5%. No significant difference between fetal tin levels from rats treated with SnCl₂ and the control group could be detected. Following oral TPTC administration, tin was present in maternal liver, kidney and brain in high concentrations. Following the oral administration of SnCl₂, the tin level was highest in bone and kidney, but none could be detected in the brain.