title: Ovarian endocrine disruption underlies premature reproductive senescence following environmentally relevant chronic exposure to the aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin.
abstract: The aryl hydrocarbon receptor (AHR) mediates the effects of many endocrine disruptors and contributes to the loss of fertility in polluted environments. While previous work has focused on mechanisms of short-term endocrine disruption and ovotoxicity in response to AHR ligands, we have shown recently that chronic exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces premature reproductive senescence in female rats without depletion of ovarian follicular reserves. In the current study, premature reproductive senescence was induced using a range of low-dose exposure to TCDD (0, 1, 5, 50, and 200 ng kg(-1) wk(-1)) beginning in utero and continuing until the transition to reproductive senescence. Doses of 50 and 200 ng TCDD kg(-1) wk(-1) delayed the age at vaginal opening and accelerated the loss of normal reproductive cyclicity with age without depletion of follicular reserves. Serum estradiol concentrations were decreased in a dose-dependent fashion (> or = 5 ng kg(-1) wk(-1)) across the estrous cycle in perisenescent rats still displaying normal cyclic vaginal cytology. Serum FSH, LH, and progesterone profiles were unchanged by TCDD. The loss of reproductive cyclicity following chronic exposure to TCDD was not accompanied by decreased responsiveness to GnRH. Ovarian endocrine disruption is the predominant functional change preceding the premature reproductive senescence induced by chronic exposure to low doses of the AHR-specific ligand TCDD.
authors.affiliation: Center for Reproductive Sciences, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
authors.forename: Zhanquan
authors.initials: Z
authors.lastname: Shi
authors.forename: Kelli E
authors.initials: KE
authors.lastname: Valdez
authors.forename: Alison Y
authors.initials: AY
authors.lastname: Ting
authors.forename: Anita
authors.initials: A
authors.lastname: Franczak
authors.forename: Steve L
authors.initials: SL
authors.lastname: Gum
authors.forename: Brian K
authors.initials: BK
authors.lastname: Petroff
mesh_terms: D000818:Animals; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000494:pharmacology*; D004958:Estradiol / Q000378:metabolism; D004971:Estrus / Q000378:metabolism; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006062:Gonadotropins / Q000378:metabolism; D010053:Ovary / Q000187:drug effects* / Q000503:physiopathology*; D010902:Pituitary Gland / Q000187:drug effects; D000072317:Polychlorinated Dibenzodioxins / Q000008:administration & dosage*; D011374:Progesterone / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018336:Receptors, Aryl Hydrocarbon / Q000819:agonists*; D012098:Reproduction / Q000187:drug effects*; D013997:Time Factors; D014621:Vagina / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology
chemical_list: D004785:Environmental Pollutants; D006062:Gonadotropins; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol