Altered prostate growth and daily sperm production in male mice exposed prenatally to subclinical doses of 17 alpha-ethinyl oestradiol

Approximately 2 million women in the USA and Europe continue taking oral co ntraceptives each year during undetected pregnancy due primarily to non-com pliance and also to individual variation in sensitivity to hormones in the contraceptives. Prenatal exposure to oral contraceptives containing 17 alph a -ethinyl oestradiol (EE) has generally not been associated with an increa sed incidence of externally observable malformations at birth. The purpose of this study was to assess effects on reproductive organs in adult male mi ce that had been exposed during gestation day 0 through 17 (equivalent to g estation week 16 in humans) to clinically relevant (similar to0.5 mug/kg/da y) and lower doses of EE. Doses used in this study ranged from 0.002 to 2 m ug/kg/day. By 5 months of age, prostate weight was significantly (P < 0.05) higher than controls in most treatment groups of EE (0.02-2 <mu>g/kg). Pro static androgen receptor populations were significantly elevated only in th e 0.02 mug/kg group, suggesting different mechanisms for the increase in pr ostate weight at different doses. Daily sperm production (DSP) and DSP per gramme of testis were reduced in all treatment groups during adolescence, b ut not later in adulthood. These findings are consistent with prior studies showing that prenatal exposure of mice to very low doses of a number of oe strogenic chemicals can alter the adult male reproductive system without ca using gross external malformations.