ANTIESTROGENIC ACTIVITY OF LEAD

Lead is a widely spread environmental pollutant known to affect both m ale and female reproductive systems in humans and experimental animals . The present study investigated the effect of an acute exposure to le ad (75 mg lead per gram of body weight) 1 or 24 h before hormone treat ment on different parameters of estrogen stimulation in the rat uterus . Lead pretreatment enhanced some parameters of estrogen stimulation a nd inhibited other estrogenic responses, and the remaining parameters were unaltered. The interaction with responses to estrogen was differe nt depending on whether lead pretreatment was 1 or 24 h before hormone stimulation. The estrogenic responses mostly affected were uterine eo sinophilia, endometrial edema, uterine luminal epithelial hypertrophy, and mitosis in various-but not all-uterine cell types. In some cell t ypes, estrogen-induced mitotic response developed earlier under the ef fect of lead exposure. Results revealed an interaction with the differ ent mechanisms of estrogen action in the uterus at various levels, tha t some cell types are more sensitive to lead than others, and that the effect of exposure changed with time after lead pretreatment. The rel evance of the results are discussed in relation to lead-induced infert ility, mutagenicity, and carcinogenicity; possible mechanisms of actio n are proposed. (C) 1998 by John Wiley & Sons, Inc.