Adverse effects of diisooctyl phthalate on the male rat reproductive development following prenatal exposure

- Effects of DIOP (DIOP, CAS 27554-26-3) were examined in rats after prenatal exposure.
- DIOP induced dose-related reduction of fetal testicular testosterone production.
- DIOP produced reproductive abnormalities in male fetal and adult offspring.

In a first study, rats were given diisooctyl phthalate (DIOP, CAS 27554-26-3) at 0, 0.1, 0.5, and 1 g/kg/day, by gavage, on gestation days 6-20 (GD). There was a significant increase in resorptions at 1 g/kg/day and a reduction in fetal weights at 0.5 and 1 g/kg/day. Malpositioned testes were observed in fetuses at 1 g/kg/day, and supernumerary lumbar ribs and ossification delay at 0.5 and 1 g/kg/day. In a follow-up study, DIOP administered on GD 12-19 reduced fetal testicular testosterone at 0.1 g/kg/day and above. Finally, postnatal reproductive assessment was conducted in adult male offspring prenatally exposed to DIOP on GD 12-21. Abnormalities of reproductive system (e.g. hypospadias, non scrotal testes, and hypospermatogenesis) were observed in a few adult males at 0.5 g/kg/day, and with a high incidence at 1 g/kg/day. Thus, DIOP displayed an antiandrogenic activity and disrupted the male reproductive development.