Chlordecone (Kepone) exposure in the neonate selectively alters brain and pituitary endorphin levels in prepuberal and adult rats.

It has been reported that the pituitary [Met5]-enkephalin system was regulated by estrogen. Since chlordecone exhibits estrogen-like activity, we explored the possibility that the pituitary level of [Met5]-enkephalin might be altered by this neurotoxicant. A single injection of chlordecone (1 mg/pup on day 4 of age) reduced the level of [Met5]-enkephalin at 70 and 120 days of age in male rats but not in females. Such treatment failed to alter the pituitary levels of beta-endorphin in either sex. However, the same treatment caused a transient reduction in the hypothalamic beta-endorphin level in both male and female rats without affecting the levels of other neuropeptides in the hypothalamus and other brain regions. These results suggest that hypothalamo-pituitary axis may be the primary neural target affected by chlordecone and estrogen-like activity may be related to the chlordecone-elicited decrease in pituitary [Met5]-enkephalin level.