Interaction of estradiol and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in an ovulation model: evidence for systemic potentiation and local ovarian effects.
Immature rats were treated with estradiol cypionate, (ECP, 0, 0.1, 1, or 2 mg/kg s.c.) followed 24 h later by TCDD (0 or 10 microg/kg orally). Follicular development was induced with eCG [5 or 10 IU subcutaneously (s.c.)] followed by an ovulatory dose of hCG (10 IU s. c.). Inhibition of ovulation by TCDD was potentiated by ECP in hypophysectomized but not intact rats. Only hypophysectomized rats exposed systemically to TCDD and ECP exhibited weight loss. Pair feeding mimicked the combined effects of TCDD and ECP in hypophysectomized rats. In another experiment, intact rats received ECP s.c. (0 or 2 mg/kg) and TCDD into the ovarian bursa (0 or 250 ng). Another group of intact rats received TCDD orally (10 microg/kg) and ECP into the ovarian bursa (0 or 1.5 microg). Blockade of ovulation by systemic or local TCDD was alleviated by ECP pretreatment. Estrogen increased the systemic toxicity of TCDD in rats whereas antagonizing its direct ovarian effects.
Petroff
B K
BK
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, G011 Lied Building, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA.
Gao
X
X
Rozman
K K
KK
Terranova
P F
PF
D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004357:Drug Synergism; D004785:Environmental Pollutants / Q000633:toxicity*; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D007016:Hypophysectomy; D007279:Injections, Subcutaneous; D009929:Organ Size / Q000187:drug effects; D010053:Ovary / Q000187:drug effects* / Q000473:pathology; D010060:Ovulation / Q000187:drug effects*; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011374:Progesterone / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley
D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D011374:Progesterone; D004958:Estradiol