Estradiol valerate as a possible endocrine reproductive disruptor: evidence from an in vivo rat model.

We used an in vivo rat model to demonstrate that low-dose intradermal exposure to E(2) valerate has an inverse effect on the female's estrus cycle pattern and can significantly reduce litter size. These results suggest that, under certain circumstances, environmental exposure to exogenous estrogens may play a role as an endocrine disruptor and adversely affect reproductive outcome.