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Uenoyama Y, Tsukamura H. KNDy neurones and GnRH/LH pulse generation: Current understanding and future aspects. J Neuroendocrinol 2023; 35:e13285. [PMID: 37232103 DOI: 10.1111/jne.13285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/31/2023] [Accepted: 04/26/2023] [Indexed: 05/27/2023]
Abstract
Uncovering the central mechanism underlying mammalian reproduction is warranted to develop new therapeutic approaches for reproductive disorders in humans and domestic animals. The present study focused on the role of arcuate kisspeptin neurones (also known as KNDy neurones) as an intrinsic gonadotropin-releasing hormone (GnRH) pulse generator, which plays a fundamental role in mammalian reproduction via the stimulation of pituitary gonadotropin synthesis and release and thereby in gametogenesis and steroidogenesis in the gonads of mammals. We also discuss the mechanism that inhibits pulsatile GnRH/gonadotropin release under a negative energy balance, considering that reproductive disorders often occur during malnutrition in humans and livestock.
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Affiliation(s)
| | - Hiroko Tsukamura
- Laboratory of Animal Reproduction, Nagoya University, Nagoya, Japan
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Tapia GP, Agostinelli LJ, Chenausky SD, Padilla JVS, Navarro VI, Alagh A, Si G, Thompson RH, Balivada S, Khan AM. Glycemic Challenge Is Associated with the Rapid Cellular Activation of the Locus Ceruleus and Nucleus of Solitary Tract: Circumscribed Spatial Analysis of Phosphorylated MAP Kinase Immunoreactivity. J Clin Med 2023; 12:2483. [PMID: 37048567 PMCID: PMC10095283 DOI: 10.3390/jcm12072483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/24/2023] [Accepted: 03/02/2023] [Indexed: 03/31/2023] Open
Abstract
Rodent studies indicate that impaired glucose utilization or hypoglycemia is associated with the cellular activation of neurons in the medulla (Winslow, 1733) (MY), believed to control feeding behavior and glucose counterregulation. However, such activation has been tracked primarily within hours of the challenge, rather than sooner, and has been poorly mapped within standardized brain atlases. Here, we report that, within 15 min of receiving 2-deoxy-d-glucose (2-DG; 250 mg/kg, i.v.), which can trigger glucoprivic feeding behavior, marked elevations were observed in the numbers of rhombic brain (His, 1893) (RB) neuronal cell profiles immunoreactive for the cellular activation marker(s), phosphorylated p44/42 MAP kinases (phospho-ERK1/2), and that some of these profiles were also catecholaminergic. We mapped their distributions within an open-access rat brain atlas and found that 2-DG-treated rats (compared to their saline-treated controls) displayed greater numbers of phospho-ERK1/2+ neurons in the locus ceruleus (Wenzel and Wenzel, 1812) (LC) and the nucleus of solitary tract (>1840) (NTS). Thus, the 2-DG-activation of certain RB neurons is more rapid than perhaps previously realized, engaging neurons that serve multiple functional systems and which are of varying cellular phenotypes. Mapping these populations within standardized brain atlas maps streamlines their targeting and/or comparable mapping in preclinical rodent models of disease.
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Affiliation(s)
- Geronimo P. Tapia
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
- Ph.D. Program in Bioscience, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Lindsay J. Agostinelli
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Sarah D. Chenausky
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
- M.S. Program in Biology, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Jessica V. Salcido Padilla
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
- M.S. Program in Biology, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Vanessa I. Navarro
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
- Ph.D. Program in Bioscience, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Amy Alagh
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Gabriel Si
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Richard H. Thompson
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
- School of Information, The University of Texas at Austin, Austin, TX 78701, USA
| | - Sivasai Balivada
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Arshad M. Khan
- UTEP Systems Neuroscience Laboratory, Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
- Border Biomedical Research Center, The University of Texas at El Paso, El Paso, TX 79968, USA
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Tsuchida H, Nonogaki M, Takizawa M, Inoue N, Uenoyama Y, Tsukamura H. Enkephalin-δ Opioid Receptor Signaling Mediates Glucoprivic Suppression of LH Pulse and Gluconeogenesis in Female Rats. Endocrinology 2023; 164:6967063. [PMID: 36592113 DOI: 10.1210/endocr/bqac216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023]
Abstract
Energy availability is an important regulator of reproductive function at various reproductive phases in mammals. Glucoprivation induced by 2-deoxy-D-glucose (2DG), an inhibitor of glucose utilization, as an experimental model of malnutrition suppresses the pulsatile release of GnRH/LH and induces gluconeogenesis. The present study was performed with the aim of examining whether enkephalin-δ-opioid receptor (DOR) signaling mediates the suppression of pulsatile GnRH/LH release and gluconeogenesis during malnutrition. The administration of naltrindole hydrochloride (NTI), a selective DOR antagonist, into the third ventricle blocked the suppression of LH pulses and part of gluconeogenesis induced by IV 2DG administration in ovariectomized rats treated with a negative feedback level of estradiol-17 β (OVX + low E2). The IV 2DG administration significantly increased the number of Penk (enkephalin gene)-positive cells coexpressing fos (neuronal activation marker gene) in the paraventricular nucleus (PVN), but not in the arcuate nucleus (ARC) in OVX + low E2 rats. Furthermore, double in situ hybridization for Penk/Pdyn (dynorphin gene) in the PVN revealed that approximately 35% of the PVN Penk-expressing cells coexpressed Pdyn. Double in situ hybridization for Penk/Crh (corticotropin-releasing hormone gene) in the PVN and Penk/Kiss1 (kisspeptin gene) in the ARC revealed that few Penk-expressing cells coexpressed Crh and Kiss1. Taken together, these results suggest that central enkephalin-DOR signaling mediates the suppression of pulsatile LH release during malnutrition. Moreover, the current study suggests that central enkephalin-DOR signaling is also involved in gluconeogenesis during malnutrition in female rats.
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Affiliation(s)
- Hitomi Tsuchida
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Miku Nonogaki
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Marina Takizawa
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Naoko Inoue
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yoshihisa Uenoyama
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Hiroko Tsukamura
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
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Tsuchida H, Kawai N, Yamada K, Takizawa M, Inoue N, Uenoyama Y, Tsukamura H. Central µ-Opioid Receptor Antagonism Blocks Glucoprivic LH Pulse Suppression and Gluconeogenesis/Feeding in Female Rats. Endocrinology 2021; 162:6322534. [PMID: 34270714 DOI: 10.1210/endocr/bqab140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 12/27/2022]
Abstract
Energetic status often affects reproductive function, glucose homeostasis, and feeding in mammals. Malnutrition suppresses pulsatile release of the gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) and increases gluconeogenesis and feeding. The present study aims to examine whether β-endorphin-μ-opioid receptor (MOR) signaling mediates the suppression of pulsatile GnRH/LH release and an increase in gluconeogenesis/feeding induced by malnutrition. Ovariectomized female rats treated with a negative feedback level of estradiol-17β (OVX + low E2) receiving 2-deoxy-D-glucose (2DG), an inhibitor of glucose utilization, intravenously (iv) were used as a malnutrition model. An administration of D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), a selective MOR antagonist, into the third ventricle blocked the suppression of the LH pulse and increase in gluconeogenesis/feeding induced by iv 2DG administration. Histological analysis revealed that arcuate Kiss1 (kisspeptin gene)-expressing cells and preoptic Gnrh1 (GnRH gene)-expressing cells co-expressed little Oprm1 (MOR gene), while around 10% of arcuate Slc17a6 (glutamatergic marker gene)-expressing cells co-expressed Oprm1. Further, the CTOP treatment decreased the number of fos-positive cells in the paraventricular nucleus (PVN) in OVX + low E2 rats treated with iv 2DG but failed to affect the number of arcuate fos-expressing Slc17a6-positive cells. Taken together, these results suggest that the central β-endorphin-MOR signaling mediates the suppression of pulsatile LH release and that the β-endorphin may indirectly suppress the arcuate kisspeptin neurons, a master regulator for GnRH/LH pulses during malnutrition. Furthermore, the current study suggests that central β-endorphin-MOR signaling is also involved in gluconeogenesis and an increase in food intake by directly or indirectly acting on the PVN neurons during malnutrition in female rats.
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Affiliation(s)
- Hitomi Tsuchida
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Narumi Kawai
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Koki Yamada
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Marina Takizawa
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Naoko Inoue
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yoshihisa Uenoyama
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Hiroko Tsukamura
- Laboratory of Animal Reproduction, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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