title: Central estrogen action sites involved in prepubertal restraint of pulsatile luteinizing hormone release in female rats.
abstract: The present study aimed to determine estrogen feedback action sites to mediate prepubertal restraint of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) release in female rats. Wistar-Imamichi strain rats were ovariectomized (OVX) and received a local estradiol-17β (estradiol) or cholesterol microimplant in several brain areas, such as the medial preoptic area (mPOA), paraventricular nucleus, ventromedial nucleus and arcuate nucleus (ARC), at 20 or 35 days of age. Six days after receiving the estradiol microimplant, animals were bled to detect LH pulses at 26 or 41 days of age, representing the pre- or postpubertal period, respectively. Estradiol microimplants in the mPOA or ARC, but not in other brain regions, suppressed LH pulses in prepubertal OVX rats. Apparent LH pulses were found in the postpubertal period in all animals bearing estradiol or cholesterol implants. It is unlikely that pubertal changes in responsiveness to estrogen are due to a change in estrogen receptor (ER) expression, because the number of ERα-immunoreactive cells and mRNA levels of Esr1, Esr2 and Gpr30 in the mPOA and ARC were comparable between the pre- and postpubertal periods. In addition, kisspeptin or GnRH injection overrode estradiol-dependent prepubertal LH suppression, suggesting that estrogen inhibits the kisspeptin-GnRH cascade during the prepubertal period. Thus, estrogen-responsive neurons located in the mPOA and ARC may play key roles in estrogen-dependent prepubertal restraint of GnRH/LH secretion in female rats.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Uenoyama
authors.forename: Akira
authors.initials: A
authors.lastname: Tanaka
authors.forename: Kenji
authors.initials: K
authors.lastname: Takase
authors.forename: Shunji
authors.initials: S
authors.lastname: Yamada
authors.forename: Vutha
authors.initials: V
authors.lastname: Pheng
authors.forename: Naoko
authors.initials: N
authors.lastname: Inoue
authors.forename: Kei-ichiro
authors.initials: K
authors.lastname: Maeda
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tsukamura
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D015914:Estrogen Replacement Therapy; D025461:Feedback, Physiological / Q000187:drug effects; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000097:blood / Q000378:metabolism; D007700:Kinetics; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009928:Organ Specificity; D010052:Ovariectomy / Q000009:adverse effects; D011301:Preoptic Area / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D012741:Sexual Maturation
chemical_list: D004343:Drug Implants; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; C520305:Gper1 protein, rat; D009419:Nerve Tissue Proteins; D043562:Receptors, G-Protein-Coupled; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone