Anti-androgen effects of cypermethrin on the amino- and carboxyl-terminal interaction of the androgen receptor.

The pyrethroid insecticide, cypermethrin has been demonstrated to be an environmental anti-androgen in the androgen receptor (AR) reporter gene assay. The amino- and carboxyl-terminal (N/C) interaction is required for transcription potential of the AR. In order to characterize the anti-androgen effects of cypermethrin involved in the N/C interaction of AR, the mammalian two-hybrid assay has been developed in the study. The fusion vectors pVP16-ARNTD, pM-ARLBD and the pG5CAT Reporter Vector were cotransfected into the CV-1 cells. The assay displayed appropriate response to the potent, classical AR agonist 5α-dihydrotestosterone (DHT) and known AR antagonist nilutamide. The N/C interaction was induced by DHT from 10(-11)M to 10(-5)M in a dose-dependent manner. Nilutamide did not activate N/C interaction, while inhibited DHT-induced AR N/C interaction at the concentrations from 10(-7)M to 10(-5)M. Treatment of CV-1 cells with cypermethrin alone did not activate the reporter CAT. Cypermethrin significantly decreased the DHT-induced reporter CAT expression at the higher concentration of 10(-5)M. The mammalian two-hybrid assay provides a promising tool both for defining mechanism involved in AR N/C interaction of EDCs and for screening of chemicals with androgen agonistic and antagonistic activities. Cypermethrin exhibits inhibitory effects on the DHT-induced AR N/C interaction, while the potency is weaker than that of nilutamide.
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