Assessment of estrogenic and androgenic activities of tetramethrin in vitro and in vivo assays.
Tetramethrin, a synthetic pyrethroid insecticide, is used globally for agriculture, and thus potential environmental exposure to tetramethrin is a concern. Environmental chemicals that are hormonally active (particularly estrogen or androgen) may adversely affect the reproductive and endocrine systems. However, little is known about the estrogenic and androgenic activities of tetramethrin. In this study, uterine CaBP-9k gene expression assay and a uterotrophic assay were conducted for estrogenic activity assessment of tetramethrin, and a Hershberger assay was conducted for androgenic activity. Estrogen receptor (ERalpha and ERbeta) protein levels were also measured in tetramethrin-treated rat uteri. Northern blot analysis showed reduction in uterine CaBP-9k mRNA levels in response to tetramethrin, as well as when rats were given both tetramethrin and 17beta-estradiol (E2). In the uterotrophic assay using 18-d-old female Sprague-Dawley rats, subcutaneous treatment with tetramethrin (5 to 800 mg/kg/day) for 3 d led to a statistically significant decrease in absolute and relative uterine wet weights at all doses tested. Moreover, tetramethrin blocked the effect of E2 on uterine weights. In addition, tetramethrin reduced absolute and relative vaginal wet weights, and also inhibited the increases of vaginal weights produced by E2. Tetramethrin showed no androgenic on antiandrogenic activities in the Hershberger assay. These results suggest that tetramethrin might exert endocrine-disrupting effects on female rats through antiestrogenic action.
Kim
Soon Sun
SS
National Institute of Toxicological Research, Korea Food and Drug Administration, Seoul.
Kwack
Seung Jun
SJ
Lee
Rhee Da
RD
Lim
Kwon Jo
KJ
Rhee
Gyu Seek
GS
Seok
Ji Hyun
JH
Kim
Byung Ho
BH
Won
Yong-Hyuck
YH
Lee
Geun-Shik
GS
Jeung
Eui-Bae
EB
Lee
Byung-Mu
BM
Park
Kui-Lea
KL
D000726:Androgen Antagonists / Q000633:toxicity; D000818:Animals; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D020847:Estrogen Receptor Modulators / Q000633:toxicity*; D047628:Estrogen Receptor alpha / Q000032:analysis / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000032:analysis / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D005837:Genitalia, Male / Q000033:anatomy & histology / Q000187:drug effects; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011722:Pyrethrins / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D014621:Vagina / Q000187:drug effects / Q000473:pathology
D000726:Androgen Antagonists; D002135:Calcium-Binding Proteins; D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D007306:Insecticides; D011722:Pyrethrins; D012333:RNA, Messenger; C009424:tetramethrin