FURTHER EVALUATION OF THE DEVELOPMENTAL TOXICITY OF TRIBUTYLTIN CHLORIDE IN RATS

The objective of this study was to further evaluate the developmental toxicity of tributyltin chloride (TBTCl) in rats. Pregnant rats were g iven TBTCl by gastric intubation at a dose of 25, 50 or 100 mg/kg on d ays 7-9, days 10-12 or days 13-15 of pregnancy. A significant increase in the incidence of post-implantation loss was found in the groups tr eated with TBTCl on days 7-9 at 25 and 50 mg/kg and on days 10-12 at 1 00 mg/kg, but not in the groups treated with TBTCl on days 13-15. No s ignificant increase in the incidence of malformed fetuses was observed after treatment with TBTCl on days 7-9. A significantly increased inc idence of malformed fetuses was detected when TBTCl was given on days 10-12 at 100 mg/kg and on days 13-15 at 25, 50 and 100 mg/kg. The most predominant malformation was cleft palate. It could be concluded that the manifestation of deviant development induced by TBTCl varies with the developmental stage at the time of administration and TBTCl posse sses teratogenic potential with developmental phase specificity.