Maternal exposure of low dose of TCDD modulates the expression of estrogen receptor subunits of male gonads in offspring.
We have analyzed the effects of low-dose transplacental and lactational exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gene expression relating to the dioxin and sexual hormone cascade, and demonstrated the effects on testicular growth and sexual maturation in male offspring rats. TCDD (10 ng/kg) was administered to dams on Days 7 and 14 of gestation, and on Days 0, 7 and 14 after delivery. Gene expression of cytochrome P450 family 1 subfamily A polypeptide 1 (CYP1A1) in the liver of 17-day-old rats was significantly increased compared with controls. Furthermore, expression of estrogen receptors (ER)alpha and ERbeta was significantly increased at 17 and 42 days old, respectively in the testis of TCDD-administered rats compared with controls. Although testicular weight and the seminiferous tubule diameter were increased in 17-day-old rats, there was no difference in the number of germ cells between TCDD-treated and control animals. The expressions of androgen receptor and inhibin subunit genes were not significantly changed. These findings suggest that low-dose exposure of TCDD leads to unusual development of the testis by perturbation of steroid hormone homeostasis.
Ohyama
Kenji
K
Interdisciplinary Graduate School of Medical and Engineering Sciences, University of Yamanashi, Yamanashi, Japan.
Ohta
Masanori
M
Sano
Tomoaki
T
Sato
Kazumasa
K
Nakagomi
Yoshiko
Y
Shimura
Yoshie
Y
Yamano
Yoshiaki
Y
D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000235:genetics / Q000378:metabolism; D001835:Body Weight; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D008099:Liver / Q000378:metabolism; D008297:Male; D009929:Organ Size; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011944:Receptors, Androgen / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000187:drug effects*
C497398:ARNT protein, rat; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D011944:Receptors, Androgen; D011960:Receptors, Estrogen; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D019363:Cytochrome P-450 CYP1A1