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Song J, Choi SY. Arcuate Nucleus of the Hypothalamus: Anatomy, Physiology, and Diseases. Exp Neurobiol 2023; 32:371-386. [PMID: 38196133 PMCID: PMC10789173 DOI: 10.5607/en23040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 12/24/2023] [Accepted: 12/27/2023] [Indexed: 01/11/2024] Open
Abstract
The hypothalamus is part of the diencephalon and has several nuclei, one of which is the arcuate nucleus. The arcuate nucleus of hypothalamus (ARH) consists of neuroendocrine neurons and centrally-projecting neurons. The ARH is the center where the homeostasis of nutrition/metabolism and reproduction are maintained. As such, dysfunction of the ARH can lead to disorders of nutrition/metabolism and reproduction. Here, we review various types of neurons in the ARH and several genetic disorders caused by mutations in the ARH.
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Affiliation(s)
- Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Hwasun 58128, Korea
| | - Seok-Yong Choi
- Department of Biomedical Sciences, Chonnam National University Medical School, Hwasun 58128, Korea
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2
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Kovács DK, Eitmann S, Berta G, Kormos V, Gaszner B, Pétervári E, Balaskó M. Aging Changes the Efficacy of Central Urocortin 2 to Induce Weight Loss in Rats. Int J Mol Sci 2023; 24:8992. [PMID: 37240340 PMCID: PMC10219457 DOI: 10.3390/ijms24108992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/04/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Middle-aged obesity and aging cachexia present healthcare challenges. Central responsiveness to body-weight-reducing mediators, e.g., to leptin, changes during aging in a way, which may promote middle-aged obesity and aging cachexia. Leptin is connected to urocortin 2 (Ucn2), an anorexigenic and hypermetabolic member of the corticotropin family. We aimed to study the role of Ucn2 in middle-aged obesity and aging cachexia. The food intake, body weight and hypermetabolic responses (oxygen consumption, core temperature) of male Wistar rats (3, 6, 12 and 18 months) were tested following intracerebroventricular injections of Ucn2. Following one central injection, Ucn2-induced anorexia lasted for 9 days in the 3-month, 14 days in the 6-month and 2 days in the 18-month group. Middle-aged 12-month rats failed to show anorexia or weight loss. Weight loss was transient (4 days) in the 3-month, 14 days in the 6-month and slight but long-lasting in the 18-month rats. Ucn2-induced hypermetabolism and hyperthermia increased with aging. The age-dependent changes in the mRNA expression of Ucn2 detected by RNAscope in the paraventricular nucleus correlated with the anorexigenic responsiveness. Our results show that age-dependent changes in Ucn2 may contribute to middle-aged obesity and aging cachexia. Ucn2 shows potential in the prevention of middle-aged obesity.
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Affiliation(s)
- Dóra K. Kovács
- Institute for Translational Medicine, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
| | - Szimonetta Eitmann
- Institute for Translational Medicine, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
| | - Gergely Berta
- Department of Medical Biology, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
| | - Viktória Kormos
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
| | - Balázs Gaszner
- Department of Anatomy, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Szigeti út 12., 7624 Pecs, Hungary
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3
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Garnsey MR, Smith AC, Polivkova J, Arons AL, Bai G, Blakemore C, Boehm M, Buzon LM, Campion SN, Cerny M, Chang SC, Coffman K, Farley KA, Fonseca KR, Ford KK, Garren J, Kong JX, Koos MRM, Kung DW, Lian Y, Li MM, Li Q, Martinez-Alsina LA, O'Connor R, Ogilvie K, Omoto K, Raymer B, Reese MR, Ryder T, Samp L, Stevens KA, Widlicka DW, Yang Q, Zhu K, Fortin JP, Sammons MF. Discovery of the Potent and Selective MC4R Antagonist PF-07258669 for the Potential Treatment of Appetite Loss. J Med Chem 2023; 66:3195-3211. [PMID: 36802610 DOI: 10.1021/acs.jmedchem.2c02012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The melanocortin-4 receptor (MC4R) is a centrally expressed, class A GPCR that plays a key role in the regulation of appetite and food intake. Deficiencies in MC4R signaling result in hyperphagia and increased body mass in humans. Antagonism of MC4R signaling has the potential to mitigate decreased appetite and body weight loss in the setting of anorexia or cachexia due to underlying disease. Herein, we report on the identification of a series of orally bioavailable, small-molecule MC4R antagonists using a focused hit identification effort and the optimization of these antagonists to provide clinical candidate 23. Introduction of a spirocyclic conformational constraint allowed for simultaneous optimization of MC4R potency and ADME attributes while avoiding the production of hERG active metabolites observed in early series leads. Compound 23 is a potent and selective MC4R antagonist with robust efficacy in an aged rat model of cachexia and has progressed into clinical trials.
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Affiliation(s)
| | - Aaron C Smith
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Jana Polivkova
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Autumn L Arons
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Guoyun Bai
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | | | - Markus Boehm
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Leanne M Buzon
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Sarah N Campion
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Matthew Cerny
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Shiao-Chi Chang
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Karen Coffman
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | | | - Kari R Fonseca
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Kristen K Ford
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Jeonifer Garren
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Jimmy X Kong
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Martin R M Koos
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Daniel W Kung
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Yajing Lian
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Monica M Li
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Qifang Li
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | | | | | - Kevin Ogilvie
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Kiyoyuki Omoto
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Brian Raymer
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Matthew R Reese
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Tim Ryder
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | - Lacey Samp
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
| | | | | | - Qingyi Yang
- Pfizer, Incorporated, Cambridge, Massachusetts 02139, United States
| | - Kaicheng Zhu
- Pfizer, Incorporated, Groton, Connecticut 06340, United States
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4
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Füredi N, Mikó A, Gaszner B, Feller D, Rostás I, Tenk J, Solymár M, Balaskó M, Pétervári E. Activity of the Hypothalamic Melanocortin System Decreases in Middle-Aged and Increases in Old Rats. J Gerontol A Biol Sci Med Sci 2019; 73:438-445. [PMID: 29099963 DOI: 10.1093/gerona/glx213] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/27/2017] [Indexed: 01/22/2023] Open
Abstract
Appearance of middle-aged obesity and aging anorexia both in humans and rodents suggests a role for regulatory alterations. Hypothalamic melanocortin agonist, α-melanocyte-stimulating hormone (α-MSH) produced in the arcuate nucleus (ARC), reduces body weight via inducing hypermetabolism and anorexia mainly through melanocortin 4 receptors (MC4Rs) in the paraventricular nucleus (PVN). Orexigenic ARC-derived agouti-related protein (AgRP) is an inverse agonist on MC4R in the PVN. Previously, we demonstrated that characteristic age-related shifts in the catabolic effects of α-MSH may contribute both to middle-aged obesity and aging anorexia. Responsiveness to α-MSH decreases in middle-aged rats compared with young adults, whereas in old age it rises again significantly. We hypothesized corresponding age-related dynamics of endogenous melanocortins. Therefore, we quantified mRNA gene expression and peptide or protein level of α-MSH, AgRP, and MC4R in the ARC and PVN of male Wistar rats of five age groups (from young to old). Immunofluorescence and quantitative reverse transcriptase polymerase chain reaction were applied. α-MSH and MC4R immunoreactivities in the ARC and PVN declined in middle-aged and increased together with their expressions in aging rats. AgRP gene expression but not its immunoreactivity increased in aging rats. Our results demonstrate that age-dependent changes of endogenous melanocortins contribute to middle-aged obesity and aging anorexia.
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Affiliation(s)
- Nóra Füredi
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary.,Department of Anatomy, Medical School, University of Pécs, Hungary
| | - Alexandra Mikó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Balázs Gaszner
- Department of Anatomy, Medical School, University of Pécs, Hungary
| | - Diána Feller
- Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, University of Pécs, Hungary
| | - Ildikó Rostás
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Judit Tenk
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Margit Solymár
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
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5
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Differential effects of chronic stress in young-adult and old female mice: cognitive-behavioral manifestations and neurobiological correlates. Mol Psychiatry 2018; 23:1432-1445. [PMID: 29257131 DOI: 10.1038/mp.2017.237] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 10/01/2017] [Accepted: 10/10/2017] [Indexed: 02/07/2023]
Abstract
Stress-related psychopathology is highly prevalent among elderly individuals and is associated with detrimental effects on mood, appetite and cognition. Conversely, under certain circumstances repeated mild-to-moderate stressors have been shown to enhance cognitive performance in rodents and exert stress-inoculating effects in humans. As most stress-related favorable outcomes have been reported in adolescence and young-adulthood, this apparent disparity could result from fundamental differences in how aging organisms respond to stress. Furthermore, given prominent age-related alterations in sex hormones, the effect of chronic stress in aging females remains a highly relevant yet little studied issue. In the present study, female C57BL/6 mice aged 3 (young-adult) and 20-23 (old) months were subjected to 8 weeks of chronic unpredictable stress (CUS). Behavioral outcomes were measured during the last 3 weeks of the CUS protocol, followed by brain dissection for histological and molecular end points. We found that in young-adult female mice, CUS resulted in decreased anxiety-like behavior and enhanced cognitive performance, whereas in old female mice it led to weight loss, dysregulated locomotion and memory impairment. These phenotypes were paralleled by differential changes in the expression of hypothalamic insulin and melanocortin-4 receptors and were consistent with an age-dependent reduction in the dynamic range of stress-related changes in the hippocampal transcriptome. Supported by an integrated microRNA (miRNA)-mRNA expression analysis, the present study proposes that, when confronted with ongoing stress, neuroprotective mechanisms involving the upregulation of neurogenesis, Wnt signaling and miR-375 can be harnessed more effectively during young-adulthood. Conversely, we suggest that aging alters the pattern of immune activation elicited by stress. Ultimately, interventions that modulate these processes could reduce the burden of stress-related psychopathology in late life.
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6
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Feichtinger RG, Pétervári E, Zopf M, Vidali S, Aminzadeh-Gohari S, Mayr JA, Kofler B, Balaskó M. Effects of alpha-melanocyte-stimulating hormone on mitochondrial energy metabolism in rats of different age-groups. Neuropeptides 2017; 64:123-130. [PMID: 27614713 DOI: 10.1016/j.npep.2016.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 12/12/2022]
Abstract
Hypothalamic alpha-melanocyte-stimulating hormone (α-MSH) is a key catabolic mediator of energy homeostasis. Its anorexigenic and hypermetabolic effects show characteristic age-related alterations that may be part of the mechanism of middle-aged obesity and geriatric anorexia/cachexia seen in humans and other mammals. We aimed to investigate the role of α-MSH in mitochondrial energy metabolism during the course of aging in a rodent model. To determine the role of α-MSH in mitochondrial energy metabolism in muscle, we administered intracerebroventricular (ICV) infusions of α-MSH for 7-days to different age-groups of male Wistar rats. The activities of oxidative phosphorylation complexes I to V and citrate synthase were determined and compared to those of age-matched controls. We also quantified mitochondrial DNA (mtDNA) copy number and measured the expression of the master regulators of mitochondrial biogenesis, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and peroxisome proliferator-activated receptor gamma (PPARγ). The peptide reduced weight gain in juvenile rats to one fifth of that of controls and increased the weight loss in older animals by about five fold. Mitochondrial DNA copy number inversely correlated with changes in body weight in controls, but not in α-MSH-treated animals. The strong increase in body weight in young rats was associated with a low mtDNA copy number and high PPARγ mRNA levels in controls. Expression of PGC-1α and PPARγ declined with age, whereas OXPHOS and citrate synthase enzyme activities were unchanged. In contrast, α-MSH treatment suppressed OXPHOS enzyme and citrate synthase activity. In conclusion, our results showed age-related differences in the metabolic effects of α-MSH. In addition, administration of α-MSH suppressed citrate synthase and OXPHOS activities independent of age. These findings suggest that α-MSH exposure may inhibit mitochondrial biogenesis.
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Affiliation(s)
- René G Feichtinger
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Michaela Zopf
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Silvia Vidali
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Sepideh Aminzadeh-Gohari
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Johannes A Mayr
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Laura Bassi Centre of Expertise-THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
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7
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Mikó A, Füredi N, Tenk J, Rostás I, Soós S, Solymár M, Székely M, Balaskó M, Brunner SM, Kofler B, Pétervári E. Acute central effects of alarin on the regulation on energy homeostasis. Neuropeptides 2017; 64:117-122. [PMID: 27625299 DOI: 10.1016/j.npep.2016.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/04/2016] [Indexed: 12/17/2022]
Abstract
Hypothalamic neuropeptides influence the main components of energy balance: metabolic rate, food intake, body weight as well as body temperature, by exerting either an overall anabolic or catabolic effect. The contribution of alarin, the most recently discovered member of the galanin peptide family to the regulation of energy metabolism has been suggested. Our aim was to analyze the complex thermoregulatory and food intake-related effects of alarin in rats. Adult male Wistar rats received different doses of alarin (0.3; 1; 3 and 15μg corresponding approximately to 0.1, 0.33, 1, and 5 nmol, respectively) intracerebroventricularly. Regarding thermoregulatory analysis, oxygen consumption (indicating metabolic rate), core temperature and heat loss (assessed by tail skin temperature) were recorded in an Oxymax indirect calorimeter system complemented with thermocouples and Benchtop thermometer. In order to investigate potential prostaglandin-mediated mechanisms of the hyperthermic effect of alarin, effects of intraperitoneally applied non-selective (indomethacin, 2mg/kg) or selective cyclooxygenase inhibitor (COX-2 inhibitor meloxicam, 1; 2mg/kg) were tested. Effects of alarin on daytime and nighttime spontaneous food intake, as well as, 24-h fasting-induced re-feeding were recorded in an automated FeedScale system. Alarin increased oxygen consumption with simultaneous suppression of heat loss leading to a slow coordinated rise in core temperature. Both applied COX-inhibitors suppressed this action. Alarin failed to induce daytime food intake, but suppressed spontaneous nighttime and also fasting-induced re-feeding food intake. Alarin appears to elicit a slow anorexigenic and prostaglandin-mediated, fever-like hyperthermic response in rats. Such a combination would characterize a catabolic mediator. The potential involvement of alarin in sickness behavior may be assumed.
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Affiliation(s)
- Alexandra Mikó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Nóra Füredi
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Judit Tenk
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Ildikó Rostás
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Szilvia Soós
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Margit Solymár
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Miklós Székely
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Susanne M Brunner
- Laura Bassi Centre of Expertise - THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kofler
- Laura Bassi Centre of Expertise - THERAPEP, Research Program for Receptor Biochemistry and Tumor Metabolism, Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria.
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary.
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Melanocortin 4 receptor ligands modulate energy homeostasis through urocortin 1 neurons of the centrally projecting Edinger-Westphal nucleus. Neuropharmacology 2017; 118:26-37. [DOI: 10.1016/j.neuropharm.2017.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 02/15/2017] [Accepted: 03/02/2017] [Indexed: 11/24/2022]
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9
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Yehuda S, Rabinovitz S. The Role of Essential Fatty Acids in Anorexia Nervosa and Obesity. Crit Rev Food Sci Nutr 2017; 56:2021-35. [PMID: 26068122 DOI: 10.1080/10408398.2013.809690] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The two basic questions in food intake study are what we eat, and how much do we eat. Most research is directed toward the control of how much is eaten. This is likely the result of the increased number of individuals with eating disorders in the Western world. Feeding behavior is highly complex, and is controlled by many psychological, physiological, biochemical, and immunological factors. The aim of this review is to clarify the involvement of fatty acids in eating disorders such as anorexia and binge eating disorder. The review will describe the modified fatty acid profile observed in individuals with anorexia or binge eating disorder, and discuss on what factors fatty acids can exert beneficial effects. In addition, the differences and similarities between anorexia and binge eating disorder will be discussed. We suggest that beneficial effects of essential fatty acids on both anorexia and binge eating disorder can be explained by the stabilizing effect of those fatty acids on the neuronal membrane fluidity index.
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Affiliation(s)
- Shlomo Yehuda
- a Psychopharmacology Lab , Department of Psychology, Bar Ilan University , Ramat Gan , Israel
| | - Sharon Rabinovitz
- a Psychopharmacology Lab , Department of Psychology, Bar Ilan University , Ramat Gan , Israel.,b School of Criminology, University of Haifa , Mount Carmel , Israel
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Tenk J, Rostás I, Füredi N, Mikó A, Solymár M, Soós S, Gaszner B, Feller D, Székely M, Pétervári E, Balaskó M. Age-related changes in central effects of corticotropin-releasing factor (CRF) suggest a role for this mediator in aging anorexia and cachexia. GeroScience 2017; 39:61-72. [PMID: 28299639 PMCID: PMC5352590 DOI: 10.1007/s11357-017-9962-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/20/2016] [Indexed: 11/29/2022] Open
Abstract
Hypothalamic corticotropin-releasing factor (CRF) lays downstream to catabolic melanocortins and at least partly mediates their catabolic effects. Age-related changes in the melanocortin system (weak responsiveness in middle-aged and a strong one in old rats) have been shown to contribute to middle-aged obesity and later to aging anorexia and cachexia of old age groups. We hypothesized that catabolic (anorexigenic and hypermetabolic) CRF effects vary with aging similarly to those of melanocortins. Thus, we aimed to test whether age-related variations of CRF effects may also contribute to middle-aged obesity and aging anorexia leading to weight loss of old age groups. Food intake, body weight, core temperature, heart rate, and activity were recorded in male Wistar rats of young, middle-aged, aging, and old age groups (from 3 to 24 months) during a 7-day intracerebroventricular CRF infusion (0.2 μg/μl/h) in a biotelemetric system. In addition, CRF gene expression was also assessed by quantitative RT-PCR in the paraventricular nucleus (PVN) of intact animals of the same age groups. The infusion suppressed body weight in the young, aging, and old rats, but not in middle-aged animals. Weak anorexigenic and hypermetabolic effects were detected in the young, whereas strong anorexia (without hypermetabolism) developed in the oldest age groups in which post mortem analysis showed also a reduction of retroperitoneal fat mass. CRF gene expression in the PVN increased with aging. Our results support the potential contribution of age-related changes in CRF effects to aging anorexia and cachexia. The role of the peptide in middle-aged obesity cannot be confirmed.
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Affiliation(s)
- Judit Tenk
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Ildikó Rostás
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Nóra Füredi
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Alexandra Mikó
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Margit Solymár
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Szilvia Soós
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Balázs Gaszner
- Department of Anatomy, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Diana Feller
- Department of Pharmaceutical Biotechnology, Medical School, University of Pecs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Miklós Székely
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, 12 Szigeti str, Pécs, H-7624, Hungary.
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11
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Navarro M. The Role of the Melanocortin System in Drug and Alcohol Abuse. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2017; 136:121-150. [DOI: 10.1016/bs.irn.2017.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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12
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Tenk J, Rostás I, Füredi N, Mikó A, Soós S, Solymár M, Gaszner B, Székely M, Pétervári E, Balaskó M. Acute central effects of corticotropin-releasing factor (CRF) on energy balance: Effects of age and gender. Peptides 2016; 85:63-72. [PMID: 27637621 DOI: 10.1016/j.peptides.2016.09.005] [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: 06/06/2016] [Revised: 09/12/2016] [Accepted: 09/12/2016] [Indexed: 10/21/2022]
Abstract
Previously demonstrated age-related changes in the catabolic melanocortin system that may contribute to middle-aged obesity and aging anorexia, raise the question of the potential involvement of corticotropin-releasing factor (CRF) in these phenomena, as this catabolic hypothalamic mediator acts downstream to melanocortins. Catabolic effects of CRF were shown to be mediated by both CRF1 (hypermetabolism) and CRF2 (anorexia) receptors. To test the potential role of CRF in age-related obesity and aging anorexia, we investigated acute central effects of the peptide on energy balance in male and female rats during the course of aging. Effects of an intracerebroventricular CRF injection on food intake (FI), oxygen-consumption (VO2), core- and tail skin temperatures (Tc and Ts) were studied in male and female Wistar rats of five different age-groups (from 3- to 24-month). Anorexigenic responsiveness was tested during 180-min re-feeding (FeedScale) following 24-h fasting. Thermoregulatory analysis was performed by indirect calorimetry (Oxymax) complemented by thermocouples recording Tc and Ts (indicating heat loss). CRF suppressed FI in 3-month male and female animals. In males, CRF-induced anorexia declined with aging, whereas in females it was maintained in all groups. The peptide increased VO2 and Tc in all male age-groups, while the weaker hypermetabolic response characterizing 3-month females declined rapidly with aging. Thus, age-related alterations in acute central anorexigenic and hypermetabolic effects of CRF show different non-parallel patterns in males and females. Our findings underline the importance of gender differences. They also call the attention to the differential age-related changes in the CRF1 and CRF2 receptor systems.
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Affiliation(s)
- Judit Tenk
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Ildikó Rostás
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Nóra Füredi
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Alexandra Mikó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Szilvia Soós
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Margit Solymár
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Balázs Gaszner
- Department of Anatomy, Medical School, University of Pécs, Hungary
| | - Miklós Székely
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Erika Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - Márta Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary.
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13
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Rostás I, Tenk J, Mikó A, Füredi N, Soós S, Solymár M, Lengyel A, Székely M, Gaszner B, Feller D, Pétervári E, Balaskó M. Age-related changes in acute central leptin effects on energy balance are promoted by obesity. Exp Gerontol 2016; 85:118-127. [PMID: 27780783 DOI: 10.1016/j.exger.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 12/19/2022]
Abstract
Leptin is a key catabolic regulator of food intake (FI) and energy expenditure. Both aging and obesity have been shown to induce leptin-resistance. The present study aimed to analyze age-related changes in the anorexigenic and hypermetabolic responsiveness to acute intracerebroventricular leptin administration in different age-groups of normally fed male Wistar rats (adult and old rats from 3 to 24months of age, NF3 to NF24, respectively). The expressions of the long form of the leptin receptor (Ob-Rb) and inhibitory SOCS3 genes were also assessed by quantitative RT-PCR in the arcuate nucleus (ARC). The influence of high-fat diet-induced obesity (HF) on the anorexigenic leptin effects were also tested in younger and older middle-aged groups (HF6 and HF12). Leptin-induced anorexia varied with age: leptin suppressed re-feeding FI (following 48-h fasting) strongly in young adult (NF3), but not in younger or older middle-aged (NF6 or NF12) or in aging (NF18) rats. However, anorexigenic leptin effects reached statistical significance again in old NF24 rats. Leptin-induced hypermetabolism, on the other hand, showed monotonous age-related decline and disappeared by old age. Ob-Rb expression declined until 12months of age followed by a partial recovery in NF18 and NF24 groups. On the other hand, SOCS3 expression was high in NF6 and NF18 and to some extent in NF24 rats. Age-related alterations of Ob-Rb and SOCS3 expression in the ARC may partly contribute to the explanation of age-related variations in anorexigenic but not hypermetabolic leptin effects. High-fat diet-induced obesity was associated with resistance to leptin-induced anorexia in HF6, similar to that seen in NF6. However, instead of the expected leptin-resistance in HF12, a strong leptin-induced suppression of re-feeding was detected in these obese middle-aged rats. Our results suggest that acute central effects of leptin on anorexia and hypermetabolism change in disparate ways during aging, implying separate mechanisms (e.g. signal transduction pathways) of different leptin actions. The age-related pattern shown by leptin-induced anorexia may contribute to the explanation of middle-aged obesity, and partly to that of aging anorexia. Our findings concerning obese rats are in accord with previous observations on anorexigenic effects of peripherally administered cholecystokinin: diet-induced obesity appeared to accelerate the development of age-related regulatory alterations. Similarly, our present data also raise the possibility that chronic diet-induced obesity promotes responsiveness to centrally applied leptin at least concerning anorexigenic effects.
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Affiliation(s)
- I Rostás
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - J Tenk
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - A Mikó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - N Füredi
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - S Soós
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - M Solymár
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - A Lengyel
- Department of Biochemistry and Medical Chemistry, University of Pécs, Hungary
| | - M Székely
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - B Gaszner
- Department of Anatomy, Medical School, University of Pecs, Hungary
| | - D Feller
- Department of Pharmaceutical Biotechnology, Medical School, University of Pecs, Hungary
| | - E Pétervári
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary
| | - M Balaskó
- Institute for Translational Medicine, Medical School, University of Pécs, Hungary.
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14
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Regulatory Alterations of Energy Homeostasis in Spontaneously Hypertensive Rats (SHR). J Mol Neurosci 2016; 59:521-30. [DOI: 10.1007/s12031-016-0771-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 05/13/2016] [Indexed: 01/01/2023]
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15
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Morley JE. Peptides and aging: Their role in anorexia and memory. Peptides 2015; 72:112-8. [PMID: 25895851 DOI: 10.1016/j.peptides.2015.04.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/03/2015] [Accepted: 04/04/2015] [Indexed: 12/16/2022]
Abstract
The rapid aging of the world's population has led to a need to increase our understanding of the pathophysiology of the factors leading to frailty and cognitive decline. Peptides have been shown to be involved in the pathophysiology of frailty and cognitive decline. Weight loss is a major component of frailty. In this review, we demonstrate a central role for both peripheral peptides (e.g., cholecystokinin and ghrelin) and neuropeptides (e.g., dynorphin and alpha-MSH) in the pathophysiology of the anorexia of aging. Similarly, peripheral peptides (e.g., ghrelin, glucagon-like peptide 1, and cholecystokinin) are modulators of memory. A number of centrally acting neuropeptides have also been shown to modulate cognitive processes. Amyloid-beta peptide in physiological levels is a memory enhancer, while in high (pathological) levels, it plays a key role in the development of Alzheimer's disease.
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Affiliation(s)
- John E Morley
- Divisions of Geriatric Medicine and Endocrinology, Saint Louis University School of Medicine, St Louis, MO, United States.
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16
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Rostás I, Füredi N, Tenk J, Mikó A, Solymár M, Soós S, Székely M, Pétervári E, Balaskó M. Age-related alterations in the central thermoregulatory responsiveness to alpha-MSH. J Therm Biol 2015; 49-50:9-15. [DOI: 10.1016/j.jtherbio.2015.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/13/2015] [Accepted: 01/23/2015] [Indexed: 01/17/2023]
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17
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Armbruszt S, Figler M, Ábrahám H. Stability of CART peptide expression in the nucleus accumbens in aging. ACTA BIOLOGICA HUNGARICA 2015; 66:1-13. [PMID: 25740434 DOI: 10.1556/abiol.66.2015.1.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aging is accompanied by changes of several anorexigenic and orexigenic neuropeptides expressed in various brain areas that control food intake and these changes correlate with senescent anorexia. During aging expression of cocaine- and amphetamine-regulated transcript (CART) peptide was reported to be reduced in the hypothalamic nuclei related to food intake. Although CART peptide is abundant in the nucleus accumbens that also plays a crucial role in the food intake regulation, no data is available about the CART peptide expression in this region through aging. In the present study, CART peptide immunoreactivity was compared in the nucleus accumbens of young adult (4- and 7-month-old) middle-aged (15-month-old) and aging (25-32-month-old) Long-Evans rats. The density of CART-immunoreactive cells and axon terminals in the nucleus accumbens was measured with computer-aided densitometry. CART-immunodensity was similar in the old rats and in the younger animals without significant difference between age groups. In addition, no gender-difference was observed when CART-immunoreactivities in the nucleus accumbens of male and female animals were compared. Our results indicate that CART peptide expression in the nucleus accumbens is stable in adults and does not change with age.
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Affiliation(s)
- Simon Armbruszt
- University of Pécs Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences Pécs Hungary
| | - Mária Figler
- University of Pécs Institute of Nutritional Sciences and Dietetics, Faculty of Health Sciences Pécs Hungary
| | - Hajnalka Ábrahám
- University of Pécs Central Electron Microscopic Laboratory, Faculty of Medicine Pécs Hungary
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18
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Banki E, Pakai E, Gaszner B, Zsiboras C, Czett A, Bhuddi PRP, Hashimoto H, Toth G, Tamas A, Reglodi D, Garami A. Characterization of the thermoregulatory response to pituitary adenylate cyclase-activating polypeptide in rodents. J Mol Neurosci 2014; 54:543-54. [PMID: 24994541 DOI: 10.1007/s12031-014-0361-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/23/2014] [Indexed: 12/19/2022]
Abstract
Administration of the long form (38 amino acids) of pituitary adenylate cyclase-activating polypeptide (PACAP38) into the central nervous system causes hyperthermia, suggesting that PACAP38 plays a role in the regulation of deep body temperature (T b). In this study, we investigated the thermoregulatory role of PACAP38 in details. First, we infused PACAP38 intracerebroventricularly to rats and measured their T b and autonomic thermoeffector responses. We found that central PACAP38 infusion caused dose-dependent hyperthermia, which was brought about by increased thermogenesis and tail skin vasoconstriction. Compared to intracerebroventricular administration, systemic (intravenous) infusion of the same dose of PACAP38 caused significantly smaller hyperthermia, indicating a central site of action. We then investigated the thermoregulatory phenotype of mice lacking the Pacap gene (Pacap (-/-)). Freely moving Pacap (-/-) mice had higher locomotor activity throughout the day and elevated deep T b during the light phase. When the Pacap (-/-) mice were loosely restrained, their metabolic rate and T b were lower compared to their wild-type littermates. We conclude that PACAP38 causes hyperthermia via activation of the autonomic cold-defense thermoeffectors through central targets. Pacap (-/-) mice express hyperkinesis, which is presumably a compensatory mechanism, because under restrained conditions, these mice are hypometabolic and hypothermic compared to controls.
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Affiliation(s)
- Eszter Banki
- Department of Anatomy PTE-MTA "Lendulet" PACAP Research Team, Medical School, University of Pecs, Pecs, Hungary
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Pétervári E, Rostás I, Soós S, Tenk J, Mikó A, Füredi N, Székely M, Balaskó M. Age versus nutritional state in the development of central leptin resistance. Peptides 2014; 56:59-67. [PMID: 24680735 DOI: 10.1016/j.peptides.2014.03.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 03/05/2014] [Accepted: 03/09/2014] [Indexed: 02/06/2023]
Abstract
Leptin, a catabolic adiposity signal acts in the hypothalamus via suppressing food intake and inducing hypermetabolism. Age and obesity are accompanied by leptin resistance. The present study aimed to clarify which components of the catabolic leptin effects are influenced most strongly by aging and which ones by nutritional state-induced alterations in body composition. In our biotelemetric study the effects of a 7-day intracerebroventricular leptin infusion on various parameters of energy balance (food intake, body weight, oxygen consumption, heart rate and body temperature) were analyzed in male Wistar rats of different age-groups (from 3 to 24 months) and nutritional states (normally fed, diet-induced obese and calorie-restricted). Leptin resistance of older animals affected hypermetabolic actions, whereas leptin induced anorexia in all age-groups. Weight reducing effect of leptin diminished in middle-aged and aging animals to become significant again in the oldest group. In diet-induced obese rats leptin-induced hypermetabolism of the young rats and hypermetabolism plus anorexia of the aging ones were suppressed. Calorie-restriction reduced body weight and fat mass to a similar extent in all age-groups. It strongly enhanced leptin-induced hypermetabolism at all ages and prevented the manifestation of anorexigenic actions of leptin with the exception of the oldest group. This latter finding suggests an unexpected increase of responsiveness to anorexigenic leptin actions in old rats. Accordingly, anorexia and hypermetabolism change in disparate ways with aging. Nutritional state predominantly influences hypermetabolic leptin actions. Resistance to both hypermetabolic and anorexigenic actions were promoted by obesity, while calorie-restriction enhanced responsiveness to leptin, especially in old rats.
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Affiliation(s)
- Erika Pétervári
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
| | - Ildikó Rostás
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
| | - Szilvia Soós
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
| | - Judit Tenk
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
| | - Alexandra Mikó
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
| | - Nóra Füredi
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
| | - Miklós Székely
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary.
| | - Márta Balaskó
- Department of Pathophysiology and Gerontology, Medical School, University of Pécs, Hungary, 12. Szigeti str., H-7624 Pécs, Hungary
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Balaskó M, Rostás I, Füredi N, Mikó A, Tenk J, Cséplő P, Koncsecskó-Gáspár M, Soós S, Székely M, Pétervári E. Age and nutritional state influence the effects of cholecystokinin on energy balance. Exp Gerontol 2013; 48:1180-8. [DOI: 10.1016/j.exger.2013.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 07/03/2013] [Accepted: 07/12/2013] [Indexed: 12/29/2022]
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Balaskó M, Soós S, Párniczky A, Koncsecskó-Gáspár M, Székely M, Pétervári E. Anorexic effect of peripheral cholecystokinin (CCK) varies with age and body composition (Short communication). ACTA ACUST UNITED AC 2012; 99:166-72. [DOI: 10.1556/aphysiol.99.2012.2.10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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23
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Pétervári E, Szabad Á, Soós S, Garami A, Székely M, Balaskó M. Central alpha-MSH infusion in rats: Disparate anorexic vs. metabolic changes with aging. ACTA ACUST UNITED AC 2011; 166:105-11. [DOI: 10.1016/j.regpep.2010.10.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 08/30/2010] [Accepted: 10/04/2010] [Indexed: 12/24/2022]
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Soos S, Petervari E, Szekely M, Jech-Mihalffy A, Balasko M. Complex catabolic effects of central alpha-MSH infusion in rats of altered nutritional states: differences from leptin. J Mol Neurosci 2010; 43:209-16. [PMID: 20953734 DOI: 10.1007/s12031-010-9462-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 10/05/2010] [Indexed: 01/15/2023]
Abstract
The hypothalamic melanocortin (MC) system is a major catabolic regulator of energy balance: it suppresses food intake (FI), elevates metabolic rate, and reduces body weight (BW). The primary activator of the MC system [mainly via the alpha-melanocyte stimulating hormone (alpha-MSH)] is the adipocyte-derived leptin. With increasing BW, resistance develops to leptin-induced anorexia, but independent of this, in genetically modified animals, some alpha-MSH actions were maintained. We investigated the responsiveness of the MC system in its complexity (FI vs. metabolic correlates) in genetically intact male Wistar rats of different nutritional states (and different leptin sensitivities), i.e., in rats aged 2 months [normally fed (NF2)] or 6 months [calorie-restricted (CR6), fed ad libitum (NF6), and high-fat diet-induced obese (HF6) groups]. A 7-day-long, 1-μg/μl/h intracerebroventricular infusion of alpha-MSH reduced BW in all groups, particularly in NF6 and NF2 animals, and even CR6 rats lost BW upon alpha-MSH infusion (in contrast to leptin administration). Anorexia developed in NF2-NF6 and less in CR6 groups, and some FI fall was also seen in HF6 rats. The hypermetabolic effects (temperature/heart rate elevations) were most pronounced in CR6 and next in HF6 rats. These data suggest that alpha-MSH responsiveness is maintained in various forms (depending on nutritional state), despite obesity-induced leptin resistance.
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Affiliation(s)
- Szilvia Soos
- Department of Pathophysiology and Gerontology, Medical School, University of Pecs, 12 Szigeti ut, Pecs H-7624, Hungary
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