Persistent vaginal estrus and serum hormones after chlordecone (kepone) treatment of adult female rats.

The effects of chlordecone on vaginal estrus and neuroendocrine responses were examined in adult ovariectomized and intact females. Persistent vaginal estrus was seen in females given 50 mg/kg or more of chlordecone. The development of vaginal estrus was similar to that seen in ovariectomized females after treatment with estrogen. Since chlordecone is known to have estrogen-like effects on the reproductive system, the persistent vaginal estrus probably results from this estrogen-like action and chlordecone's long half-life in the organism. Neuroendocrine effects of chlordecone also resembled, to some degree, estrogen's effects on pituitary secretions. Chlordecone increased serum prolactin and decreased serum luteinizing hormone (LH) in ovariectomized females 30 to 36 hr after a single exposure to 50 mg/kg of the pesticide. Basal LH levels were not altered in intact females, but the proestrous LH surge was suppressed by 36 hr after treatment. Both basal and proestrous levels of prolactin were suppressed. Unlike the effects of estrogen, serum follicle stimulating hormone was not altered by chlordecone. These results indicate an effect on the hypothalamic pituitary axis by chlordecone treatment and offer a possible explanation for the reduced fertility seen in adult females after chlordecone exposure. However, blockage of the proestrous LH surge was not obligatory for the appearance of vaginal estrus. Although chlordecone produced peripheral changes in the vaginal smear pattern as well as neuroendocrine alterations, the peripheral changes were not always indicative of the neuroendocrine events.