title: Developmental programming: postnatal steroids complete prenatal steroid actions to differentially organize the GnRH surge mechanism and reproductive behavior in female sheep.
abstract: In female sheep, estradiol (E2) stimulates the preovulatory GnRH/LH surge and receptive behavior, whereas progesterone blocks these effects. Prenatal exposure to testosterone disrupts both the positive feedback action of E2 and sexual behavior although the mechanisms remain unknown. The current study tested the hypothesis that both prenatal and postnatal steroids are required to organize the surge and sex differences in reproductive behavior. Our approach was to characterize the LH surge and mating behavior in prenatally untreated (Control) and testosterone-treated (T) female sheep subsequently exposed to one of three postnatal steroid manipulations: endogenous E2, excess E2 from a chronic implant, or no E2 due to neonatal ovariectomy (OVX). All females were then perfused at the time of the expected surge and brains processed for estrogen receptor and Fos immunoreactivity. None of the T females exposed postnatally to E2 exhibited an E2-induced LH surge, but a surge was produced in five of six T/OVX and all Control females. No surges were produced when progesterone was administered concomitantly with E2. All Control females were mounted by males, but significantly fewer T females were mounted by a male, including the T/OVX females that exhibited LH surges. The percentage of estrogen receptor neurons containing Fos was significantly influenced in a brain region-, developmental stage-, and steroid-specific fashion by testosterone and E2 treatments. These findings support the hypothesis that the feedback controls of the GnRH surge are sensitive to programming by prenatal and postnatal steroids in a precocial species.
authors: Reproductive Sciences Program, University of Michigan, Ann Arbor, Michigan, USA.
authors: Leslie M
authors: LM
authors: Jackson
authors: Andrea
authors: A
authors: Mytinger
authors: Eila K
authors: EK
authors: Roberts
authors: Theresa M
authors: TM
authors: Lee
authors: Douglas L
authors: DL
authors: Foster
authors: Vasantha
authors: V
authors: Padmanabhan
authors: Heiko T
authors: HT
authors: Jansen
mesh_terms: D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology / Q000502:physiology; D025461:Feedback, Physiological; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000187:drug effects / Q000378:metabolism; D007986:Luteinizing Hormone / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010052:Ovariectomy; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011301:Preoptic Area / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D011374:Progesterone / Q000494:pharmacology; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology; D046468:Sexual Development / Q000187:drug effects / Q000502:physiology; D012756:Sheep; D013739:Testosterone / Q000494:pharmacology*; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: D000728:Androgens; D011960:Receptors, Estrogen; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone