Normal and Abnormal Puberty Horm Res 2003;60(suppl 3):15–20 DOI: 10.1159/000074495 The Neurobiology of Female Puberty Sergio R. Ojeda a Vincent Prevot b Sabine Heger c Alejandro Lomniczi a Barbara Dziedzic d Alison Mungenast a a Division of Neuroscience, Oregon National Primate Research Center/Oregon Health and Science University, Beaverton, Ore., USA; b INSERM U422, Lille, France; c Division of Pediatric Endocrinology, Department of Pediatrics, University Children’s Hospital, Kiel, Germany; and d Department of Physiology, Medical University of Lo ´ dz ´, Lo ´ dz ´, Poland Prof. Sergio R. Ojeda Division of Neuroscience, Oregon National Primate Research Center/ Oregon Health and Science University, 505 N.W. 185th Avenue Beaverton, OR 97006 (USA) Tel. +1 503 6905303, Fax +1 503 6905384, E-Mail ojedas@ohsu.edu ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2003 S. Karger AG, Basel 0301–0163/03/0609–0015$19.50/0 Accessible online at: www.karger.com/hre Key Words Astroglial cells W Growth factors W Hypothalamus W Sexual development W Glial-neuronal communication W Onset of puberty Abstract In this review, studies are described indicating that the increase in pulsatile release of gonadotropin releasing hormone that signals the initiation of puberty requires both changes in transsynaptic communication and the activation of glia-to-neuron signaling pathways. The ma- jor players in the transsynaptic control of puberty are neurons that utilize excitatory and inhibitory amino acids as transmitters. Glial cells employ a combination of tro- phic factors and small cell-cell signaling molecules to regulate neuronal function and thus promote sexual development. A neuron-to-glia signaling pathway me- diated by excitatory amino acids serves to coordinate the simultaneous activation of transsynaptic and glia-to-neu- ron communication required for the advent of sexual maturity. Copyright © 2003 S. Karger AG, Basel Introduction Puberty is initiated by events that occur within the cen- tral nervous system and that are set in motion without the need for gonadal influences [1–3]. As a consequence of these events, the release of pulsatile gonadotropin releas- ing hormone (GnRH) into the portal vasculature that links the hypothalamus to the pituitary gland increases and pituitary gonadotropin output is stimulated, resulting in the initiation of the pubertal process. In girls, gonadotropin output begins to increase in a circadian manner (with higher levels during sleep) be- tween 8 and 10 years of age and the first menstruation occurs at an average of 12 years of age, with the first ovu- lation taking place 6–12 months later [4]. In the female monkey, a nocturnal increase in circulating gonadotropin levels is first seen between 25 and 30 months of age, men- arche occurs between 30 and 40 months of age and the first ovulation is usually seen between 40 and 50 months of age [3]. In female rats, a diurnal increase in the pulsatile release of luteinizing hormone releasing hormone is ob- served by the end of the fourth week of postnatal life and the first ovulation takes place 34–38 days after birth [1]. The pubertal activation of pulsatile GnRH secretion is not initiated within the GnRH neuronal network itself but instead is brought about by events that take place in Downloaded by: Oregon Health Sci Univ.Library 137.53.241.26 - 12/5/2013 5:00:06 PM