2001 年 14 巻 1 号 p. 83
Effects of estrogenic endocrine disrupting chemicals (EDCs) on the female reproductive tract, in addition to uterine carcinogenesis, in rats exposed at adulthood or perinatal period were investigated. In adult normal cycling and ovariectomized (OVX) rats, high dose exposure to p-tert octylphenol (OP) directly exerted estrogenic activity on the uterus and vagina, the minimum effective level being lower in OVX rats than normal cycling ones. Serum concentrations of OP were detected at similar levels in both normal cycling and OVX rats and the effects increased with a dose- and time-dependent manner, indicating that the OVX rats are more sensitive for detection of estrogenic activity of chemicals. Neonatal exposure to high dose OP showed irreversible effects on the female reproductive tract of rats. Various effects such as persistent estrus, atrophic and polycystic ovary and luminal-epithelial hyperplasia were considered to be due to disruption of the hypothalamus-pituitary-gonadal control system, whereas the inhibition of uterine gland-genesis might be direct estrogenic action of OP. Our data of perinatal or adulthood exposure to high dose estrogenic EDCs with or without carcinogen using Donryu rats provided that the EDCs promoted uterine carcinogenesis in rats.
