title: Assessment of estrogenic and androgenic activities of tetramethrin in vitro and in vivo assays.
abstract: 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.
authors.affiliation: National Institute of Toxicological Research, Korea Food and Drug Administration, Seoul.
authors.forename: Soon Sun
authors.initials: SS
authors.lastname: Kim
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Kwack
authors.forename: Rhee Da
authors.initials: RD
authors.lastname: Lee
authors.forename: Kwon Jo
authors.initials: KJ
authors.lastname: Lim
authors.forename: Gyu Seek
authors.initials: GS
authors.lastname: Rhee
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Seok
authors.forename: Byung Ho
authors.initials: BH
authors.lastname: Kim
authors.forename: Yong-Hyuck
authors.initials: YH
authors.lastname: Won
authors.forename: Geun-Shik
authors.initials: GS
authors.lastname: Lee
authors.forename: Eui-Bae
authors.initials: EB
authors.lastname: Jeung
authors.forename: Byung-Mu
authors.initials: BM
authors.lastname: Lee
authors.forename: Kui-Lea
authors.initials: KL
authors.lastname: Park
mesh_terms: 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
chemical_list: 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