[Antiandrogenic effects of cypermethrin and beta-cypermethrin].
OBJECTIVE
To investigate the antiandrogenic activities of cypermethrin and beta-cypermethrin in vitro and in vivo.


METHODS
Transcriptional activation assay based on MDA-kb2 cell was used to determine the antiandrogenic effect of cypermethrin and beta-cypermethrin in vitro. The cells were treated by 10(-8), 10(-7), 10(-6) and 10(-5) mol/L of cypermethrin and beta-cypermethrin with 1.0 nmol/L DHT at the same time. The effects of antagonism towards the androgenic receptor were studied. In in vivo assays, Hershberger assay was used to determine the antiandrogenic activities of cypermethrin and beta-cypermethrin. Six-week-old castrated male SD rats were administered by cypermethrin (7, 21 and 63 mg/kg) and beta-cypermethrin (6, 18 and 54 mg/kg). After 7-day treatments, all rats were euthanized and androgen-responsive tissues were excised and weighed respectively.


RESULTS
The in vitro experiments showed that 10(-6) and 10(-5) mol/L cypermethrin could inhibit significantly the antagonism activity towards the androgenic receptor of DHT. In in vivo tests, the weight of seminal vesicle, ventral prostate, dorsolateral prostate and preputial glands in the 63 mg/kg cypermethrin [(52.8 +/- 7.1), (42.4 +/- 8.9), (36.6 +/- 4.5) and (43.4 +/- 11.1) mg] decreased significantly compared with those in the control group. In 21 mg/kg cypermethrin treated group only the weights of ventral prostate and dorsolateral prostate decreased significantly, and in 7 mg/kg cypermethrin only the weight of dorsolateral prostate decreased (P < 0.05). For beta-cypermethrin, any antiandrogen effect in in vivo and in vitro experiments was not found in all the groups.


CONCLUSIONS
Cypermethrin is a moderate antiandrogen that elicits antiandrogenic effects at least partly by antagonizing AR and beta-cypermethrin is not an antiandrogen in our experiments.
Wu
Wei
W
Institute of Infectious Disease, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Zhang
Jun
J
Zhu
Wei
W
Zheng
Yi-fan
YF
Zhu
Hui-juan
HJ
Xu
Mei
M
Zhu
Xin-qiang
XQ
D000726:Androgen Antagonists / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D008297:Male; D009929:Organ Size; D011467:Prostate / Q000187:drug effects*; D011722:Pyrethrins / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011944:Receptors, Androgen / Q000187:drug effects; D012669:Seminal Vesicles / Q000187:drug effects
D000726:Androgen Antagonists; D011722:Pyrethrins; D011944:Receptors, Androgen; C017160:cypermethrin