title: The Central Effect of β-Endorphin and Naloxone on The Biosynthesis of GnRH and GnRH Receptor (GnRHR) in The Hypothalamic-Pituitary Unit of Follicular-Phase Ewes.
abstract: The effects of prolonged, intermittent infusion of β-endorphin or naloxone into the third cerebral ventricle of follicular-phase ewes on the expression of genes encoding GnRH and GnRHR in the hypothalamus and GnRHR in the anterior pituitary gland (AP) were examined by an enzyme-linked immunoabsorbent assay. Activation or blockade of μ-opioid receptors significantly decreased or increased the GnRH concentration and GnRHR abundance in the hypothalamus, respectively, and affected in the same way GnRHR quantity in the AP gland. The changes in the levels of GnRH and GnRHR after treatment with β-endorphin as well as following action of naloxone were reflected in fluctuations of plasma LH concentrations. On the basis of these results, it is suggested that β-endorphinergic system in the hypothalamus of follicular-phase ewes affects directly or via β-endorphin-sensitive interneurons GnRH and GnRHR biosynthesis leading to suppression in secretory activity of the hypothalamic-pituitary axis.
authors.affiliation: Department of Pharmacology and Toxicology, The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Ciechanowska
authors.affiliation: Department of Pharmacology and Toxicology, The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Łapot
authors.affiliation: Department of Pharmacology and Toxicology, The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology, Warsaw, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Mateusiak
authors.affiliation: Department of Pharmacology and Toxicology, The General Karol Kaczkowski Military Institute of Hygiene and Epidemiology, Warsaw, Poland.
authors.forename: E
authors.initials: E
authors.lastname: Paruszewska
authors.affiliation: Polish Academy of Sciences, The Museum and Institute of Zoology, Warsaw, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Malewski
authors.affiliation: Department of Neuroendocrinology, Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, Jabłonna, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Krawczyńska
authors.affiliation: Department of Neuroendocrinology, Polish Academy of Sciences, The Kielanowski Institute of Animal Physiology and Nutrition, Jabłonna, Poland.
authors.forename: F
authors.initials: F
authors.lastname: Przekop
mesh_terms: D000818:Animals; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D009270:Naloxone / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000502:physiology; D011966:Receptors, LHRH / Q000235:genetics / Q000378:metabolism*; D012756:Sheep / Q000502:physiology*; D001615:beta-Endorphin / Q000494:pharmacology*
chemical_list: D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; D009270:Naloxone; D001615:beta-Endorphin; D007986:Luteinizing Hormone