Pregnant rats were allowed to deliver naturally; day of birth was
considered postnatal day (PND) 0. At culling (PND4), pups were
redistributed to dams such that littermates were spread across litters.
While litters contained both males and females, only male pups were
tested. For the adult studies, male rats were received at 80–82 days of
age and tested 6–8 days after arrival.