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Dos-Santos RC, Reis LC, Perello M, Ferguson AV, Mecawi AS. The actions of ghrelin in the paraventricular nucleus: energy balance and neuroendocrine implications. Ann N Y Acad Sci 2019; 1455:81-97. [PMID: 31008525 DOI: 10.1111/nyas.14087] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/28/2019] [Accepted: 03/10/2019] [Indexed: 12/15/2022]
Abstract
Ghrelin is a peptide mainly produced and secreted by the stomach. Since its discovery, the impact of ghrelin on the regulation of food intake has been the most studied function of this hormone; however, ghrelin affects a wide range of physiological systems, many of which are controlled by the hypothalamic paraventricular nucleus (PVN). Several pathways may mediate the effects of ghrelin on PVN neurons, such as direct or indirect effects mediated by circumventricular organs and/or the arcuate nucleus. The ghrelin receptor is expressed in PVN neurons, and the peripheral or intracerebroventricular administration of ghrelin affects PVN neuronal activity. Intra-PVN application of ghrelin increases food intake and decreases fat oxidation, which chronically contribute to the increased adiposity. Additionally, ghrelin modulates the neuroendocrine axes controlled by the PVN, increasing the release of vasopressin and oxytocin by magnocellular neurons and corticotropin-releasing hormone by neuroendocrine parvocellular neurons, while possibly inhibiting the release of thyrotropin-releasing hormone. Thus, the PVN is an important target for the actions of ghrelin. Our review discusses the mechanisms of ghrelin actions in the PVN, and its potential implications for energy balance, neuroendocrine, and integrative physiological control.
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Affiliation(s)
- Raoni C Dos-Santos
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Luís C Reis
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Mario Perello
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, La Plata, Argentina
| | - Alastair V Ferguson
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - André S Mecawi
- Laboratory of Neuroendocrinology, Department of Biophysics, Paulista Medical School, Federal University of São Paulo, São Paulo, Brazil
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Engster KM, Kroczek AL, Rose M, Stengel A, Kobelt P. Peripheral injection of bombesin induces c-Fos in NUCB2/nesfatin-1 neurons. Brain Res 2016; 1648:46-53. [PMID: 27396908 DOI: 10.1016/j.brainres.2016.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 02/01/2023]
Abstract
As anorexigenic hormones bombesin and nucleobindin2 (NUCB2)/nesfatin-1 decrease food intake in rodents. Both hormones have been described in brain nuclei that play a role in the modulation of hunger and satiety, like the paraventricular nucleus of the hypothalamus (PVN) and the nucleus of the solitary tract (NTS). However, the direct interaction of the two hormones is unknown so far. The aim of study was to elucidate whether bombesin directly interacts with NUCB2/nesfatin-1 neurons in the PVN and NTS. Therefore, we injected bombesin intraperitoneally (ip) at two doses (26 and 32nmol/kg body weight) and assessed c-Fos activation in the PVN, arcuate nucleus (ARC) and NTS compared to vehicle treated rats (0.15M NaCl). We also performed co-localization studies with oxytocin or tyrosine hydroxylase. Bombesin at both doses increased the number of c-Fos positive neurons in the PVN (p<0.05) and NTS (p<0.05) compared to vehicle, while in the ARC no modulation was observed (p>0.05). In the PVN and NTS the number of c-Fos positive neurons colocalized with NUCB2/nesfatin-1 increased after bombesin injection compared to vehicle treatment (p<0.05). Moreover, an increase of activated NUCB2/nesfatin-1 immunoreactive neurons that co-expressed oxytocin in the PVN (p<0.05) or tyrosine hydroxylase in the NTS (p<0.05) was observed compared to vehicle. Our results show that peripherally injected bombesin activates NUCB2/nesfatin-1 neurons in the PVN and NTS giving rise to a possible interaction between bombesin and NUCB2/nesfatin-1 in the modulation of food intake.
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Affiliation(s)
- Kim-Marie Engster
- Charité Center for Internal Medicine and Dermatology, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Arthur L Kroczek
- Charité Center for Internal Medicine and Dermatology, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Matthias Rose
- Charité Center for Internal Medicine and Dermatology, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany
| | - Peter Kobelt
- Charité Center for Internal Medicine and Dermatology, Department of Psychosomatic Medicine, Charité - Universitätsmedizin Berlin, Germany.
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Miegueu P, St-Pierre DH, Munkonda MN, Lapointe M, Cianflone K. Amylin stimulates fatty acid esterification in 3T3-L1 adipocytes. Mol Cell Endocrinol 2013; 366:99-107. [PMID: 23261986 DOI: 10.1016/j.mce.2012.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 11/20/2012] [Accepted: 12/11/2012] [Indexed: 01/25/2023]
Abstract
Amylin is co-localized and co-secreted with insulin, however its direct effects on adipocytes are unexplored. In 3T3-L1 preadipocytes, amylin increased thymidine incorporation (174%; p<0.05) and Myc mRNA expression (378%; p<0.01). Amylin supplementation during differentiation enhanced triglyceride accumulation (272%; p<0.001). In 3T3-L1 adipocytes, amylin increased fatty acid uptake (238%; p<0.01) and further potentiated the effects of insulin (insulin 158%; p<0.01, amylin+insulin 335%; p<0.001 vs CTL, p<0.001 vs insulin). By contrast, amylin inhibited glycerol release in 3T3-L1 adipocytes (-50%; p<0.05) and primary adipocytes (-34%; p<0.05). Amylin stimulated cytokine secretion (monocyte chemotactic protein-1+166%, keratinocyte-derived chemokine+174%; both p<0.05) and mRNA expression of PPARγ (163%; p<0.01), C/EBPβ (121%, p<0.05), DGAT1 (157%; p<0.01), FABP4 (122%; p<0.01), and CD36 (122%; p<0.05). In human adipose tissue, mRNA expression of amylin receptor genes (CALCR and RAMP3) correlated with numerous lipid and insulin signaling genes, plasma glucose and HOMA. Altogether amylin directly stimulates fat cells, potentiates the effects of insulin and may influence insulin resistance.
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Affiliation(s)
- Pierre Miegueu
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Department of Medicine, Université Laval, Québec, QC, Canada
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Abstract
Amylin is a pancreatic B-cell hormone that plays an important role in the control of nutrient fluxes because it reduces food intake, slows gastric emptying, and reduces postprandial glucagon secretion. These actions seem to depend on a direct effect on the area postrema (AP). Subsequent to area AP activation, the amylin signal is conveyed to the forebrain via distinct relay stations. Within the lateral hypothalamic area, amylin diminishes the expression of orexigenic neuropeptides. Recent studies suggest that amylin may also play a role as a long term, adiposity signal. Similar to leptin or insulin, an infusion of amylin into the brain resulted in lower body weight gain than in controls, irrespective of the starting body weight. Interestingly, preliminary data also suggest that rats fed an energy-dense diet develop resistance to central amylin. In addition to amylin's action to control meal termination and to act as a potential adiposity signal, amylin and its agonist salmon calcitonin have recently been shown to increase energy expenditure under certain conditions. In summary, amylin may be an interesting target as a body weight lowering drug. In fact, recent studies provide evidence that amylin, especially when combined with other anorectic hormones (for example, peptide YY and leptin) has beneficial long-term effects on body weight.
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Veldhuis JD, Bowers CY. Integrating GHS into the Ghrelin System. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010:879503. [PMID: 20798846 PMCID: PMC2925380 DOI: 10.1155/2010/879503] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/30/2009] [Indexed: 12/21/2022]
Abstract
Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.
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Affiliation(s)
- Johannes D. Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN 55905, USA
| | - Cyril Y. Bowers
- Division of Endocrinology, Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Stengel A, Taché Y. Regulation of food intake: the gastric X/A-like endocrine cell in the spotlight. Curr Gastroenterol Rep 2010; 11:448-54. [PMID: 19903420 DOI: 10.1007/s11894-009-0069-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nutritional status influences hormone secretion from specialized enteroendocrine cells within the gut mucosa. These hormones regulate food intake by mediating information to central neurocircuitries in the brainstem and forebrain (eg, hypothalamic nuclei). Intestinal enteroendocrine cells were believed to be the main source of gut peptides regulating food intake. However, recent evidence highlights a specific endocrine cell within the oxyntic glands of the stomach as an important player in appetite control. Acylated ghrelin is the only known orexigenic hormone peripherally produced in gastric X/A-like cells and centrally acting to stimulate food intake. Recent advances led to the assumption that des-acylated ghrelin, coreleased with acylated ghrelin, is also involved in regulating food intake. This, and the novel observation that nesfatin-1, which inhibits food intake, is expressed in ghrelin-producing cells of the stomach, supports an important role for gastric X/A-like cells in regulating food intake. Another peptide, obestatin, was initially described as a ghrelin gene product inhibiting food intake, but subsequent studies produced controversial data and its action as an anorexic factor is doubtful. Importantly, synergistic interactions between ghrelin and intestinal peptides seem to orchestrate food intake and body weight regulation, which may have implications for understanding mechanisms leading to the treatment of obesity.
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Affiliation(s)
- Andreas Stengel
- Center for Ulcer Research and Education, Digestive Diseases Research Center, Center for Neurobiology of Stress, Building 115, Room 117, VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA
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Stengel A, Goebel M, Wang L, Taché Y. Ghrelin, des-acyl ghrelin and nesfatin-1 in gastric X/A-like cells: role as regulators of food intake and body weight. Peptides 2010; 31:357-69. [PMID: 19944123 PMCID: PMC3166546 DOI: 10.1016/j.peptides.2009.11.019] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 11/12/2009] [Accepted: 11/16/2009] [Indexed: 02/07/2023]
Abstract
Numerous peptides released from endocrine cells in the intestinal mucosa were established early on to be involved in the physiological regulation of food intake with a prominent role in termination of food ingestion when nutrients pass along the intestinal tract. Recently, peptides released from X/A-like endocrine cells of the gastric oxyntic mucosa were recognized as additional key players in the regulation of feeding and energy expenditure. Gastric X/A-like cells release the octanoylated peptide, ghrelin, the only known peripherally produced hormone stimulating food intake through interaction with growth hormone secretagogue 1a receptor (GHS-R1a). Additionally, non-octanoylated (des-acyl) ghrelin present in the circulation at higher levels than ghrelin is currently discussed as potential modulator of food intake by opposing ghrelin's action independent from GHS-R1a although the functional significance remains to be established. Obestatin, a ghrelin-associated peptide was initially reported as anorexigenic modulator of ghrelin's orexigenic action. However, subsequent reports did not support this contention. Interesting is the recent identification of nesfatin-1, a peptide derived from the nucleobindin2 gene prominently expressed in gastric X/A-like cells in different vesicles than ghrelin. Circulating nesfatin-1 levels vary with metabolic state and peripheral or central injection inhibits dark phase feeding in rodents. Overall, these data point to an important role of gastric X/A-like cells in food intake regulation through the expression of the orexigenic peptide ghrelin along with des-acyl ghrelin and nesfatin-1 capable of reducing food intake upon exogenous injection although their mechanisms of action and functional significance remain to be established.
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Affiliation(s)
- Andreas Stengel
- CURE: Digestive Diseases Research Center and Neurobiology of Stress, Digestive Diseases Division, David Geffen School of Medicine at University of California Los Angeles and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA.
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Stengel A, Goebel M, Wang L, Taché Y. Abdominal surgery activates nesfatin-1 immunoreactive brain nuclei in rats. Peptides 2010; 31:263-70. [PMID: 19944727 PMCID: PMC3166548 DOI: 10.1016/j.peptides.2009.11.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 11/17/2009] [Accepted: 11/17/2009] [Indexed: 02/06/2023]
Abstract
Abdominal surgery-induced postoperative gastric ileus is well established to induce Fos expression in specific brain nuclei in rats within 2-h after surgery. However, the phenotype of activated neurons has not been thoroughly characterized. Nesfatin-1 was recently discovered in the rat hypothalamus as a new anorexigenic peptide that also inhibits gastric emptying and is widely distributed in rat brain autonomic nuclei suggesting an involvement in stress responses. Therefore, we investigated whether abdominal surgery activates nesfatin-1-immunoreactive (ir) neurons in the rat brain. Two hours after abdominal surgery with cecal palpation under short isoflurane anesthesia or anesthesia alone, rats were transcardially perfused and brains processed for double immunohistochemical labeling of Fos and nesfatin-1. Abdominal surgery, compared to anesthesia alone, induced Fos expression in neurons of the supraoptic nucleus (SON), paraventricular nucleus (PVN), locus coeruleus (LC), Edinger-Westphal nucleus (EW), rostral raphe pallidus (rRPa), nucleus of the solitary tract (NTS) and ventrolateral medulla (VLM). Double Fos/nesfatin-1 labeling showed that of the activated cells, 99% were nesfatin-1-immunoreactive in the SON, 91% in the LC, 82% in the rRPa, 74% in the EW and VLM, 71% in the anterior parvicellular PVN, 47% in the lateral magnocellular PVN, 41% in the medial magnocellular PVN, 14% in the NTS and 9% in the medial parvicellular PVN. These data established nesfatin-1 immunoreactive neurons in specific nuclei of the hypothalamus and brainstem as part of the neuronal response to abdominal surgery and suggest a possible implication of nesfatin-1 in the alterations of food intake and gastric transit associated with such a stressor.
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Affiliation(s)
- Andreas Stengel
- CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles & Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA 90073, USA
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Interactions of gastrointestinal peptides: ghrelin and its anorexigenic antagonists. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010. [PMID: 20798884 PMCID: PMC2925274 DOI: 10.1155/2010/817457] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 10/13/2009] [Accepted: 10/19/2009] [Indexed: 12/21/2022]
Abstract
Food intake behaviour and energy homeostasis are strongly regulated by a complex system of humoral factors and nerval structures constituting the brain-gut-axis. To date the only known peripherally produced and centrally acting peptide that stimulates food intake is ghrelin, which is mainly synthesized in the stomach. Recent data indicate that the orexigenic effect of ghrelin might be influenced by other gastrointestinal peptides such as cholecystokinin (CCK), bombesin, desacyl ghrelin, peptide YY (PYY), as well as glucagon-like peptide (GLP). Therefore, we will review on the interactions of ghrelin with several gastrointestinal factors known to be involved in appetite regulation in order to elucidate the interdependency of peripheral orexigenic and anorexigenic peptides in the control of appetite.
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Inhoff T, Mönnikes H, Noetzel S, Stengel A, Goebel M, Dinh QT, Riedl A, Bannert N, Wisser AS, Wiedenmann B, Klapp BF, Taché Y, Kobelt P. Desacyl ghrelin inhibits the orexigenic effect of peripherally injected ghrelin in rats. Peptides 2008; 29:2159-68. [PMID: 18938204 PMCID: PMC2586396 DOI: 10.1016/j.peptides.2008.09.014] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 09/18/2008] [Accepted: 09/19/2008] [Indexed: 12/22/2022]
Abstract
Studies showed that the metabolic unlike the neuroendocrine effects of ghrelin could be abrogated by co-administered unacylated ghrelin. The aim was to investigate the interaction between ghrelin and desacyl ghrelin administered intraperitoneally on food intake and neuronal activity (c-Fos) in the arcuate nucleus in non-fasted rats. Ghrelin (13 microg/kg) significantly increased food intake within the first 30 min post-injection. Desacyl ghrelin at 64 and 127 microg/kg injected simultaneously with ghrelin abolished the stimulatory effect of ghrelin on food intake. Desacyl ghrelin alone at both doses did not alter food intake. Both doses of desacyl ghrelin injected separately in the light phase had no effects on food intake when rats were fasted for 12h. Ghrelin and desacyl ghrelin (64 microg/kg) injected alone increased the number of Fos positive neurons in the arcuate nucleus compared to vehicle. The effect on neuronal activity induced by ghrelin was significantly reduced when injected simultaneously with desacyl ghrelin. Double labeling revealed that nesfatin-1 immunoreactive neurons in the arcuate nucleus are activated by simultaneous injection of ghrelin and desacyl ghrelin. These results suggest that desacyl ghrelin suppresses ghrelin-induced food intake by curbing ghrelin-induced increased neuronal activity in the arcuate nucleus and recruiting nesfatin-1 immunopositive neurons.
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Affiliation(s)
- Tobias Inhoff
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology, Charité - Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany
| | - Hubert Mönnikes
- Department of Medicine and Institute of Neurogastroenterology, Martin-Luther-Hospital, Berlin, Germany
| | - Steffen Noetzel
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology, Charité - Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany
| | - Andreas Stengel
- Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division UCLA, and VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Miriam Goebel
- Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division UCLA, and VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Q. Thai Dinh
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | - Andrea Riedl
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | | | - Anna-Sophia Wisser
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology, Charité - Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany
| | - Bertram Wiedenmann
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology, Charité - Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany
| | - Burghard F. Klapp
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
| | - Yvette Taché
- Department of Medicine, CURE Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division UCLA, and VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Peter Kobelt
- Department of Medicine, Division Hepatology, Gastroenterology, and Endocrinology, Charité - Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany
- Department of Medicine, Division Psychosomatic Medicine and Psychotherapy; Charité, Campus Mitte; Universitätsmedizin Berlin, Germany
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Gonzalez N, Moody TW, Igarashi H, Ito T, Jensen RT. Bombesin-related peptides and their receptors: recent advances in their role in physiology and disease states. Curr Opin Endocrinol Diabetes Obes 2008; 15:58-64. [PMID: 18185064 PMCID: PMC2631407 DOI: 10.1097/med.0b013e3282f3709b] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Mammalian bombesin-related peptides, gastrin-releasing peptide and neuromedin B actions are mediated by two receptors (BB1-receptor, BB2-receptor), which are closely related to the orphan receptor BRS-3 (BB3-receptor). The purpose of this review is to highlight advances in the understanding of these peptides in physiology/disease states. RECENT FINDINGS Pharmacologic/receptor-knockout studies show involvement of these receptors in a number of new processes/diseases. Neuromedin B/BB1-receptor is an important physiological regulator of pituitary-thyroid function; in mediating behavior, especially feas/anxiety; in mediating satiety through different cascades than gastrin-releasing peptide/BB2 receptors and for its autocrine tumor-growth effects. Gastrin-releasing peptide/BB2-receptor plays important roles in mediating signals for pruritus, lung development/injury, small intestinal mucosal defense, and central nervous system processes such as learning/memory. The signaling mechanisms of its potent growth effects are being elucidated and their possible therapeutic targets identified. BB3-receptor knockout mice provided insights for their obesity/glucose intolerance and demonstrated that this receptor may be important in the lung response to injury, tumor growth and gastrointestinal motility. Each receptor is frequently overexpressed in human tumors and has potent growth effects. This effect is being explored to develop new antitumor treatments, such as bombesin-receptor ligands conjugated to cytotoxic agents. SUMMARY This receptor family is involved in an increasing number of central nervous system/peripheral processes physiologically and in disease states, and increased understanding of its role may lead to novel treatments.
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Affiliation(s)
- Nieves Gonzalez
- Digestive Diseases Branch, National Institutes of Health, Bethesda, Maryland 20892, USA
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Bibliography. Current world literature. Growth and development. Curr Opin Endocrinol Diabetes Obes 2007; 14:74-89. [PMID: 17940424 DOI: 10.1097/med.0b013e32802e6d87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Gourcerol G, St-Pierre DH, Taché Y. Lack of obestatin effects on food intake: should obestatin be renamed ghrelin-associated peptide (GAP)? ACTA ACUST UNITED AC 2007; 141:1-7. [PMID: 17321609 DOI: 10.1016/j.regpep.2006.12.023] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Revised: 12/23/2006] [Accepted: 12/23/2006] [Indexed: 12/28/2022]
Abstract
Obestatin is a newly identified ghrelin-associated peptide (GAP) that is derived from post-translational processing of the prepro-ghrelin gene. Obestatin has been reported initially to be the endogenous ligand for the orphan receptor G protein-coupled receptor 39 (GPR39), and to reduce refeeding- and ghrelin-stimulated food intake and gastric transit in fasted mice, and body weight gain upon chronic peripheral injection. However, recent reports indicate that obestatin is unlikely to be the endogenous ligand for GPR39 based on the lack of specific binding on GRP39 receptor expressing cells and the absence of signal transduction pathway activation. In addition, a number of studies provided convergent evidence that ghrelin injected intracerebroventricularly or peripherally did not influence food intake, body weight gain, gastric transit, gastrointestinal motility, and gastric vagal afferent activity, as well as pituitary hormone secretions, in rats or mice. Similarly, obestatin did not alter ghrelin-induced stimulation of food intake or gastric transit. Therefore, the present state-of-knowledge on obestatin and GPR39 is leaving many unanswered questions that deserve further consideration. Those relate not only to redefining the biological action of obestatin that should be renamed GAP, but also the identification of the native ligand for GPR39.
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Affiliation(s)
- G Gourcerol
- CURE: Digestive Diseases Research Center, and Center for Neurovisceral Sciences & Women's Health, David Geffen School of Medicine at UCLA, Division of Digestive Diseases, University of California, Los Angeles, USA
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