One-generation reproductive toxicity study of dietary 17 beta -estradiol (E2; CAS No. 50-28-2) in CD-1 super(()R) (Swiss) mice

There is no information on reproductive/developmental effects in mice from dietary estrogen. Therefore, 10 adult CD-1 super(()R) mice/sex/group were administered dietary 17 beta -estradiol (E2) at 0, 0.005, 0.05, 0.5, 2.5, 5, 10, and 50ppm for 2-week prebreed, mating, gestation, lactation. F1 weanlings (3/sex/litter) were necropsied and 2/sex /litter were retained, with exposure, until vaginal patency (VP) or preputial separation (PPS) and then necropsied. Results included complete infertility at 2.5-50ppm with normal mating indices. At 0.5ppm (and above), F0 adult female uterus plus cervix plus vagina weights (UCVW) were increased. At 0.5ppm: prolonged gestational length; increased F1 stillbirth index; reduced live birth index and litter size; decreased testes and epididymides weights at weaning; unaffected AGD on pnd 0 and 21; delayed PPS; increased undescended testes; unaffected prostate weight; accelerated VP; enlarged vaginas; fluid-filled uteri. At 0.05ppm: no F0 reproductive effects, increased F1 weanling UCVW; delayed PPS. The NOEL was 0.005ppm ( arrow right mu g/kg/day).