Effect of chronic exposure to lead on estrogen action in the prepubertal rat uterus

Abstract

Lead is a widely spread environmental pollutant known to affect both male and female reproductive systems in humans and in experimental animals. The present study investigated the effect of a chronic exposure to lead on different parameters of estrogen stimulation in the uteri of prepubertal rats. Chronic exposure to lead enhanced some parameters of estrogen stimulation, inhibited other estrogenic responses, while the remainder were unaltered. Estrogen-induced uterine eosinophilia (24 h), the proportion of uterine eosinophils in the mesometrium (6 h), and luminal epithelial hypertrophy and RNA content (24 h) appeared to be enhanced by lead exposure, compared to lead-unexposed control animals. Eosinophilia in the endometrium (6 h), the proportion of uterine eosinophils in the endometrium (6 and 24 h), edema in superficial and deep endometria (6 h), luminal epithelial hypertrophy (6 h), and mitotic response (cell proliferation) in all uterine cell types were inhibited by lead exposure, whereas circular myometrial hypertrophy was not significantly modified. The effects of lead exposure on responses to estrogen found in this study showed some differences with those previously reported for acute or subacute exposure to lead. The results revealed an interaction with the different mechanisms of estrogen action in the uterus at various levels, suggesting that some uterine cell types are more sensitive to lead than others. The relevance of the results for lead-induced infertility is discussed in this article, and possible mechanisms of action are proposed.

Characterizing Golden Eagle Risk to Lead and Anticoagulant Rodenticide Exposure: A Review

“…PbB in these monkeys was approximately 35 μg/dL. Also, a study in rats showed that exposure to lead can enhance some parameters of estrogen stimulation, inhibit other estrogenic responses, and some responses remain unaltered (Tchernitchin et al 2003). In that study, female rats were administered lead acetate every 3 days from age 7 days and until they were 19 days old; the PbB in these rats was approximately 47 μg/dL.…”

Genistein Selectively Inhibits Estrogen-Induced Cell Proliferation and Other Responses to Hormone Stimulation in the Prepubertal Rat Uterus

“…This dissociation was reported under several experimental conditions in the rat uterus. 7,8,12,13 The lower incidence of breast cancer in Asian women than in western women, 14 which parallels the higher amount of phytoestrogens (including soybean products) consumed by Asian women, 14 was attributed to lifestyle but not to genetic factors. 15,16 In fact, in East and Southeast Asia, the average intake of phytoestrogens is estimated to be more than 10 times higher than in the United States or Europe, 17 and plasma isoflavone concentrations are higher in Japanese women than in Europeans.…”

Daidzein–Estrogen Interaction in the Rat Uterus and Its Effect on Human Breast Cancer Cell Growth

“…The various parameters of estrogen stimulation were evaluated at the times during which their maximal response to E 2 occurs. 22,44,45 Uterine eosinophilia reaches maximal response at 6 or 24 h; endometrial edema reaches maximal response at 6 h and declines thereafter; and uterine luminal epithelial, stromal, and myometrial cell proliferation reaches maximal level responses at 24 h after hormone treatment. To allow a comparison between the effects of daidzein among the different parameters of estrogen stimulation, all responses were expressed as % of response to E 2 , that is, the value of vehicle-treated animals was considered 0% response, and the value of response to E 2 -100% response.…”

“…42,43 Cell hypertrophy (increase in cell size) was evaluated morphometrically in the above cell-types. 22,33,42,44 Human breast cancer cell culture procedure…”

“…This dissociation was reported under several experimental conditions in the rat uterus. 13,14,[19][20][21][22][23] The lower incidence of several hormonally dependent cancers in Asian women than in Western women 24 was attributed to the higher amount of diet phytoestrogensincluding soybean products-consumed by Eastern Asian women, 24,25 and suggested their possible role in breast cancer prevention. 26 For this purpose, several plant extract preparations were registered as pharmaceuticals or nutraceuticals recommended for hormone-dependent cancer prevention in climacteric women.…”