Predominant role of the hypothalamic-pituitary axis, not the ovary, in different types of abnormal cycle induction by postnatal exposure to high dose p-tert-octylphenol in rats.

To determine whether it is the hypothalamic-pituitary axis or the ovary that plays the predominant role in abnormal estrous cycling induction by postnatal exposure to estrogenic compounds, female rats were subcutaneously injected with 100mg/kg p-tert-octylphenol or vehicle for 5 or 15 days after birth (OP-PND5, OP-PND15 or control). Ovaries were exchanged between control and treated groups on PND28. Controls receiving control or OP-PND5 ovaries showed normal cycles within 4 weeks after the exchange, and corpora lutea were detected in transplanted ovaries.

Dietary indole-3-carbinol promotes endometrial adenocarcinoma development in rats initiated with N-ethyl-N'-nitro-N-nitrosoguanidine, with induction of cytochrome P450s in the liver and consequent modulation of estrogen metabolism.

Indole-3-carbinol (I3C), found in cruciferous vegetables, has been shown to suppress or promote carcinogenesis depending on various animal models. Regarding its preventive effects, I3C acts as an anti-estrogen and can induce apoptosis, but precise mechanisms remain to be determined. Since I3C induces cytochrome P450 enzymes in the liver, it affects hydroxylation of estrogens and might therefore be expected to influence endometrial adenocarcinoma development.

Maternal exposure to low doses of bisphenol a has no effects on development of female reproductive tract and uterine carcinogenesis in Donryu rats.

Effects of maternal exposure to low doses of bisphenol A (BPA), including those comparable with human exposure levels, on growth and development of the female reproductive system and uterine carcinogenesis in Donryu rats were investigated. Dams were administered BPA (0, 0.006 and 6 mg/kg/day) daily by gavage from gestation day 2 up to the day before weaning (postnatal day 21 at offspring).

Effects of estrogens and metabolites on endometrial carcinogenesis in young adult mice initiated with N-ethyl-N'-nitro-N-nitrosoguanidine.

The present study assessed effects of estrogens and their steroid metabolites on the endometrial carcinogenesis in young adult mice initiated with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG). A total of 272 female CD-1 (ICR) mice were used and equally divided into 17 groups. Mice were implanted cholesterol pellets to the back subcutis at 9 weeks of age.