Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on serum inhibin concentrations and inhibin immunostaining during follicular development in female Sprague-Dawley rats.
Intact and hypophysectomized immature rats were pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 0 or 32 microg/kg p.o.) and sacrificed throughout synchronized follicular development (0, 12, 24, 48, and 72 h after equine chorionic gonadotropin, eCG). TCDD administration to intact rats resulted in a premature elevation of serum FSH and LH by 12 h post-eCG. In intact rats pretreated with TCDD, the intensity of ovarian immunoreactivity for inhibin and the number of ovarian follicles staining for inhibin in midsaggital ovarian sections were decreased at the time of eCG administration (24 h post-TCDD) in comparison to controls. However, this decreased ovarian staining for inhibin was not associated with alterations in serum inhibin concentrations. Serum inhibin was suppressed in TCDD-treated rats when compared to intact controls only at 24 h post-eCG. Hypophysectomized animals exhibited no effect of TCDD on serum inhibin at any timepoint but did have decreased estradiol concentrations during follicular development. In summary, TCDD reduced serum concentrations of inhibin after the premature increases in FSH and LH suggesting that inhibin is not important in the initial elevation of FSH following exposure to TCDD.
Petroff
Brian K
BK
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City 66160, USA.
Gao
Xin
X
Ohshima
Ken-Ichi
K
Shi
FangXiong
F
Son
Deok-Soo
DS
Roby
Katherine F
KF
Rozman
Karl K
KK
Watanabe
Gen
G
Taya
Kazuyoshi
K
Terranova
Paul F
PF
D000818:Animals; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007016:Hypophysectomy; D007150:Immunohistochemistry; D007265:Inhibins / Q000097:blood / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D010060:Ovulation / Q000502:physiology; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013723:Teratogens / Q000633:toxicity*
D000072317:Polychlorinated Dibenzodioxins; D013723:Teratogens; D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone