Interaction of acetochlor with estrogen receptor in the rat uterus. Acetochlor - Possible endocrine modulator?

The aim of the present study was to investigate the ability of the chloroac etanilide herbicide acetochlor to interact with the endocrine system. The m odulation of the binding of [H-3]estradiol-17 beta to protamine sulphate-pr ecipitated uterine nuclear and cytoplasmic estrogen receptors was analysed for this purpose. Two different stages of reproductive life cycle of female rats, virgin and uniparous, were used. Our results demonstrate that acetoc hlor interacts in a specific manner with high-affinity limited-capacity ute rine estrogen receptors. A significant difference (p < 0.001) in estrogen r eceptor density was observed between two control groups: uniparous rats (B- max = 43.634 +/-9.516) and virgin rats (B-max = 154.375 +/- 21.462), sugges ting an intrinsic difference in the nuclear estrogen receptor levels betwee n female rats in different reproductive life cycle stages. Consequently, a different response to acetochlor treatment was noted. Exposure to acetochlo r significantly (p < 0.001) increased estrogen receptor binding activity in the nuclear fraction of uniparous female rats (B-max = 123.324 +/- 5.666) in comparison to control (B-max = 43.634 +/- 9.516). In exposed virgin fema le rats, no significant difference was detected when compared to the corres ponding control group. These results should prompt us to more thoroughly ev aluate potential hazards of acetochlor to human and wildlife endocrine syst ems.