Endocrinology and Physiology of Reproduction PDF
Preview Endocrinology and Physiology of Reproduction
EN DOCRI NOLOGY AND PHYSIOLOGY OF REPRODUCTION EN DOCRI NOLOGY AND PHYSIOLOGY OF REPRODUCTION Edited by c. P. K. Leung The University of British Columbia Vancouver, British Columbia, Canada D. T. Armstrong University of Western Ontario London, Ontario, Canada K. B. Ruf and W. H. Moger Dalhousie University Halifax, Nova Scotia, Canada and H. G. Friesen University of Manitoba Winnipeg, Manitoba, Canada Springer Science+Business Media, LLC Library of Congress Cataloging In Publication Data Endocrinology and physiology and reproduction. Most chapters were presented as plenary lectures or symposium talks at the 1986 30th Congress of the International Union of Physiological Sciences in Van- couver, B.C. Includes bibliographies and indexes. 1. Human reproduction—Endocrine aspects—Congresses. 2. Human reproduc- tion—Congresses. I. Leung, P. C. K. II. International Union of Physiological Sciences. Congress (30th: 1986: Vancouver, B.C.) [DNLM: 1. Endocrine Glands —physiology—congresses. 2. Reproduction—congresses. W3 IN84 30th 1986 / WQ 205 E565 1986] QP252.E53 1987 612'.6 87-11280 ISBN 978-1-4899-1973-1 ISBN 978-1-4899-1973-1 ISBN 978-1-4899-1971-7 (eBook) DOI 10.1007/978-1-4899-1971-7 © 1987 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1987 Softcover reprint of the hardcover 1st edition 1987 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher FOREWORD Most of the following chapters were presented as plenary lectures or symposium talks at the 1986 XXXth Congress of the International Union of Physiological Sciences in Vancouver, B.C. A distinguished international group of endocrinologists and physiologists have contributed up-to-date reviews of their particular fields. The early chapters are largely concerned with the brain and neuroendocrine mechanisms controlling the secretion of gonadotropin releasing hormone (GnRH) and its action on the anterior pitui tary gland. Later chapters focus on the gonads themselves and the systemic and intrinsic hormones influencing the functional cytology of ovarian and testicular cells. Such comprehensive subjects as sex differentiation, puberty, placentation and parturition are also discussed authoritatively. According to Pfaff and Cohen and Arai et al., gonadal steroids, especially estrogen, exert multiple effects on certain hypothalamic and preoptic neurons, including growth, protein synthesis and electrical changes, which promote plasticity and facilitate synaptogenesis. The electrophysio logy of the hypothalamic GnRH pulse generator in the rhesus monkey is reviewed more specifically by Knobil. In ovariectomized ewes, Clarke finds both positive and negative effects of estrogen on hypothalamic release of GnRH as well as on pituitary responsiveness to the peptide. Flerk6 et al. and Motta et al. describe mechanisms by which brain and pituitary peptides can influence hypothalamic function by short and ultrashort feedback circuits to modulate neural control of pituitary gonadotropin release. An involvement of the amino acid neurotransmitter y-aminobutyric acid in the control of GnRH release is also proposed by Wuttke et al. In a study of hypothalamic biogenic amines, eoen emphasizes the importance of adrenergic nerves in stimulating GnRH release. Admitting the stimulatory effects, Bergen and Leung demonstrate that electrical stimulation of the ascending dorsal midbrain noradrenergic pathway, but not the ventral tract, markedly inhibits pulsatile LH release in ovariectomized rats, supporting the existence of an inhibitory noradrenergic system in the modulation of GnRH discharge'. In the developing female rat approaching puberty, Ojeda et al. describe the inter play of ovarian estrogen, norepinephrine (NE) and vasoactive intestinal peptide (VIP) in evoking the release of sufficient GnRH to activate a proestrous ovulatory LH surge. Estrogen enhances both NE-induced prosta glandin E2 (PGE2) synthesis and PGE2-induced GnRH release. A protein kinase C-mediated pathway may also be activated in the hypothalamus and participate in stimulating GnRH discharge. Millar et al. review structural and functional characteristics of a recently discovered precursor of GnRH, as well as the biological activity of non-GnRH synthetic peptide sequences of the GnRH precursor. Two chapters by Catt et al. and Naor are concerned with biochemical mechanisms by which GnRH stimulates LH release. They agree that GnRH first stimulates a rapid phosphodiester hydrolysis of phosphatidylinositol v 4,5-biphosphate (PIP2) to inositol-triphosphate (IP3) and diacylglycerol (DG). 1P3 appears to mobilize cellular Ca2+ while DG activates protein kinase C. These findings suggest that the LH response to GnRH is mediated by two intracellular pathways involving Ca2+ and diacylglycerol as second messengers. Four chapters are concerned with mechanisms by which local and circulating hormones influence ovarian cell functions such as steroido genesis, inhibin secretion, oogenesis and luteolysis. Hsueh and colleagues have studied extensively the effects of follicle-stimulating hormone on ovarian granulosa cells in culture and find that the ability of a selected follicle(s) to become dominant while the majority of follicles become atretic cannot be explained on the basis of gonadotropin levels alone. Local modula tory factors are also important. Likewise, Armstrong et al. find that folli cular steroid biosynthesis is influenced by the local action of the Qvarian steroids themselves. Steroids represent one of the mechanisms by which follicular recruitment, growth, atresia, and ovulation may be influenced by local intraovarian factors. Dekel suggests that meiosis is arrested in the intrafollicular oocyte by the paracrine transfer of cAMP from the surrounding cumulus cells, and that the preovulatory surge of LH releases the meiotic inhibition by breaking down the communication between cumulus and oocyte. Cumulus-free oocytes resume meiosis and become fertilizable. Sheldrick and Flint propose that in the sheep oxytocin secreted by the corpus luteum may contribute to luteolysis by stimulating the release of the ovine luteolysin, prostaglandin F2Q' The oxytocin receptors in the uterus develop at the appropriate stage in the estrous cycle, and the short circuit interchange between corpus luteum and uterus may involve countercurrent distribution of the peptide and prostaglandin in the ovarian and uterine veins and arteries. Four chapters focus on the testis and its specialized cells involved in steroidogenesis and spermatogenesis. Moger et al. review the evidence that androgen steroidogenesis by the interstitial Leydig cells is influenced by catecholamines. Pomerantz and Jansz find that disruption of spermatogenesis by unilateral surgical cryptorchidism induces a hyperresponsiveness of the Leydig cells in both testes to treatment with LH in vitro. This suggests an intergonadal transfer of the influence of unilateral aspermatogenesis caused by the cryptorchidism. According to Bergh and Damber, treatment of the male rat with hCG/LH induces a rapid rise in testosterone secretion which in turn causes the local formation of at least two factors influencing testicular blood vessels, one affecting arteriolar and one increasing venular permeabi lity by attracting polymorphonuclear leukocytes. The nature and physiolo gical roles of the factors is unknown. The descent of the testis has been restudied by Wensing. The essential outgrowth of the gubernaculum appears to depend on some unknown testicular hormone other than testosterone. However, there are indications that testosterone plays a major role in the subsequent regression of the gubernaculum. Josso et al. describe the factors responsible for sexual differentiation of the fetus. Genetic and hormonal stimuli including an early anti-Mullerian hormone secreted by Sertoli cells and testosterone produced subsequently by Leydig cells induce the male alterations in organs that would otherwise develop autonomously as female structures. Female organogenesis is disrupted by exposure to male hormones such as may occur in congenital adrenal hyper plaSia. Two placental lactogens have been demonstrated by Duckworth et al. in the rat. The first, with a mGlecular weight of about 40,000 daltons, peaks at 12 days of pregnancy and is inhibited by the maternal pituitary. The second, of about half the molecular weight of the first, appears at about day 11 and peaks at day 20. Its level is markedly increased by maternal hypophysectomy or ovariectomy at midpregnancy but strongly suppressed by fetectomy. The structural relations of these and other lactogen-related molecules in the rat placenta are under study with genetic coding techniques. The volume closes with a review of hormonal influences on fetal and perinatal water metabolism, by Perks and Cassin, and Thorburn's essay on the comparative physiology of mechanisms controlling the timing of parturition. The mammalian fetus is usually successful in delaying parturition by suppres sing excitatory prostaglandin release from the maternal reproductive tract until its organ systems needed for extrauterine survival are sufficiently mature. This important process requiring precisely programmed interactions between fetus and mother exemplifies many of the neuroendocrine mechanisms encountered repeatedly in the physiology of reproduction. C.H. Sawyer Department of Anatomy University of California Los Angeles, California, USA 90024 CONTENTS SECTION I: HYPOTHALAMUS AND OTHER BRAIN AREAS Estrogen Acting on Hypothalamic Neurons May Have Trophic Effects on Those Neurons and the Cells on Which They Synapse 1 D.W. Pfaff and R.S. Cohen Gonadal Steroid Control of Synaptogenesis in the Neuroendocrine Brain ••••••• 13 Y. Arai, A. Matsumoto, and M. Nishizuka The Electrophysiology of the Hypothalamic Gonadotropic Hormone Releasing Hormone (GnRH) Pulse Generator in the Rhesus Monkey • • • • . • • • • . • . . • 23 E. Knobil Ovarian Feedback Regulation of Gonadotropin-Releasing Hormone Secretion and Action • • . • . • • • • . 27 I.J. Clarke Short and Ultrashort Feedback Control of Gonadotropin Secretion • • • • • • • • • 37 B. Flerk6, I. Merchanthaler, and G. Set&16 The Hypothalamo-Pituitary-Gonadal System: Role of Peptides and Sex Steroids •• . • • 51 M. Motta, D. Dondi, R. Maggi, E. Messi, Z. Zoppi, M. Zanisi, and F. Piva Involvement of GABA in the Neuroendocrinology of Reproduction • . • . • • • • • • • • . • • 65 W. Wuttke, H. Jarry, J. Demling, R. Wolf, and E. DUker SECTION II: PITUITARY Hypothalamic Biogenic Amines and the Regulation of Luteinizing Hormone Release in the Rat .•• 71 C.W. Coen Dual Action of Norepinephrine in the Control of Gonadotropin Release •••••••• • • • • • • • • 99 H. Bergen and P.C.K. Leung Physiological and Biochemical Dissection of Mechanisms Underlying Puberty • • • • • • • • • • • • • • • •• 113 S.R. Ojeda, H.F. Urbanski, C.E. Ahmed, L. Rogers, and D. Gonzalez Biological Activity on Non-GnRH Synthetic Peptide Sequences of the GnRH Precursor •••••••••••• • • • • 127 R.P. Millar, P.J. Wormald, M.J. Abrahamson, R.C. deL. Milton, and K. Waligora Mechanisms of GnRH Action: Interactions between GnRH-Stimulated Calcium-Phospholipid Pathways Mediating Gonadotropin Secretion • • • • 135 J.P. Chang, E. McCoy, R.O. Morgan, and K.J. Catt Phosphoinositide Turnover, Ca2+ Mobilization, and Protein Kinase C Activation in GnRH Action on Pituitary Gonadotropin Release • • • • • • • • • • • • • • • • 155 z. Naor SECTION III: GONADS The Ovarian Granulosa Cell as a Follicle-Stimulating Hormone Target Tissue • • • • • • • • • • 163 B. Kessel, X.C. Jia, J.B. Davoren, and A.J.W. Hsueh Intra-ovarian Actions of Steroids in the Regulation of Follicular Steroid Biosynthesis • • • • • • 177 D.T. Armstrong, S.A.J. Daniel, and R.E. Gore-Langton Interaction between the Oocyte and the Granulosa Cells in the Preovulatory Follicle ••••• 197 N. Dekel Secretion of Oxytocin by the Corpus Luteum and its Role in Luteolysis in the Sheep • 211 E.L. Sheldrick and A.P.F. Flint Catecholamine Effects on Leydig Cell Steroidogenesis: A Review. • • • • • • • • • • • •••• 221 W.H. Moger, 0.0. Anakwe, and P.R. Murphy Evidence for Intratesticular Factors Which Mediate the Response of Leydig Cells to Disruption of Spermatogenesis • • • • • • • • • 233 D.K. Pomerantz and G.F. Jansz hCG/LH-Induced Changes in Testicular Blood Flow, Microcirculation and Vascular Permeability in Adult Rats •• 243 A. Bergh and J.E. Damber Morphology of Normal and Abnormal Testicular Descent and the Regulation of This Process • • 261 C.J.G. Wensing x SECTION IV: FETUS AND PLACENTA Sex Differentiation 273 N. Josso The Placental Lactogen Gene Family: Structure and Regulation • • • • • • • • • •••• • • 289 M.L. Duckworth, M.C. Robertson, arid H.G. Friesen Hormonal Influences on Fetal and Perinatal Water Metabolism • • 303 A.M. Perks and S. Cassin The Orchestration of Parturition: Does the Fetus play the Tune? 331 G.D. Thorburn Author Index • 355 Subj ect Index 357 xi
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