Manipulation of pre and postnatal androgen environments and anogenital distance in rats

We examined the anogenital distance (AGD) plasticity in rats through the manipulation of the androgen environment in utero and during puberty. Dams were treated from gestation days 13–20 with vehicle, flutamide (20 mg/kg/day), di-(2-ethylhexyl) phthalate (DEHP, 750 mg/kg/day), or testosterone (1.0 mg/kg/day). After weaning, male pups were randomly assigned to one of four postnatal groups, which received the same treatments given prenatally. Sixteen treatment groups were established based on the combination of pre- and postnatal exposures. The postnatal treatments were conducted from postnatal days 23–53. In utero flutamide and DEHP exposure significantly shortened male AGD, although this effect was more pronounced in flutamide-exposed rats. Postnatal flutamide, DEHP, and testosterone induced slight but significant reductions in male AGD. Our study indicates that AGD is a stable anatomical landmark that reflects the androgen action in utero, although it can also be slightly responsive to changes in the androgen environment following pubertal exposure.