title: 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.
authors.affiliation: Laboratory of Experimental Endocrinology and Environmental Pathology, Center for Research on Environment and Biomedicine (CIMAB) and Institute of Biomedical Sciences (ICBM), University of Chile Medical School, Casilla 21104, Correo 21, Santiago, Chile.
authors.forename: Nina N
authors.initials: NN
authors.lastname: Tchernitchin
authors.forename: Andrea
authors.initials: A
authors.lastname: Clavero
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Mena
authors.forename: Cristina
authors.initials: C
authors.lastname: Unda
authors.forename: Rebeca
authors.initials: R
authors.lastname: Villagra
authors.forename: Miguel
authors.initials: M
authors.lastname: Cumsille
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Tchernitchin
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004487:Edema / Q000139:chemically induced; D004802:Eosinophilia / Q000139:chemically induced; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006652:Histological Techniques; D008938:Mitosis / Q000187:drug effects; D009942:Organometallic Compounds / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus / Q000378:metabolism*
chemical_list: D009942:Organometallic Compounds; D004958:Estradiol; C008261:lead acetate