1
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Massa MG, Scott RL, Cara AL, Cortes LR, Vander PB, Sandoval NP, Park JW, Ali SL, Velez LM, Wang HB, Ati SS, Tesfaye B, Reue K, van Veen JE, Seldin MM, Correa SM. Feeding neurons integrate metabolic and reproductive states in mice. iScience 2023; 26:107918. [PMID: 37817932 PMCID: PMC10561062 DOI: 10.1016/j.isci.2023.107918] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 07/27/2023] [Accepted: 09/12/2023] [Indexed: 10/12/2023] Open
Abstract
Balance between metabolic and reproductive processes is important for survival, particularly in mammals that gestate their young. How the nervous system coordinates this balance is an active area of study. Herein, we demonstrate that somatostatin (SST) neurons of the tuberal hypothalamus alter feeding in a manner sensitive to metabolic and reproductive states in mice. Whereas chemogenetic activation of SST neurons increased food intake across sexes, ablation decreased food intake only in female mice during proestrus. This ablation effect was only apparent in animals with low body mass. Fat transplantation and bioinformatics analysis of SST neuronal transcriptomes revealed white adipose as a key modulator of these effects. These studies indicate that SST hypothalamic neurons integrate metabolic and reproductive cues by responding to varying levels of circulating estrogens to modulate feeding differentially based on energy stores. Thus, gonadal steroid modulation of neuronal circuits can be context dependent and gated by metabolic status.
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Affiliation(s)
- Megan G. Massa
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
- Neuroscience Interdepartmental Doctoral Program, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Rachel L. Scott
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Alexandra L. Cara
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Laura R. Cortes
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Paul B. Vander
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Norma P. Sandoval
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Jae W. Park
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Sahara L. Ali
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Leandro M. Velez
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Huei-Bin Wang
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Shomik S. Ati
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Bethlehem Tesfaye
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - J. Edward van Veen
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
| | - Marcus M. Seldin
- Department of Biological Chemistry, School of Medicine, University of California – Irvine, Irvine, CA 92697, USA
| | - Stephanie M. Correa
- Department of Integrative Biology and Physiology, University of California – Los Angeles, Los Angeles, CA 90095, USA
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Kumar U, Singh S. Role of Somatostatin in the Regulation of Central and Peripheral Factors of Satiety and Obesity. Int J Mol Sci 2020; 21:ijms21072568. [PMID: 32272767 PMCID: PMC7177963 DOI: 10.3390/ijms21072568] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/29/2020] [Accepted: 04/02/2020] [Indexed: 02/06/2023] Open
Abstract
Obesity is one of the major social and health problems globally and often associated with various other pathological conditions. In addition to unregulated eating behaviour, circulating peptide-mediated hormonal secretion and signaling pathways play a critical role in food intake induced obesity. Amongst the many peptides involved in the regulation of food-seeking behaviour, somatostatin (SST) is the one which plays a determinant role in the complex process of appetite. SST is involved in the regulation of release and secretion of other peptides, neuronal integrity, and hormonal regulation. Based on past and recent studies, SST might serve as a bridge between central and peripheral tissues with a significant impact on obesity-associated with food intake behaviour and energy expenditure. Here, we present a comprehensive review describing the role of SST in the modulation of multiple central and peripheral signaling molecules. In addition, we highlight recent progress and contribution of SST and its receptors in food-seeking behaviour, obesity (orexigenic), and satiety (anorexigenic) associated pathways and mechanism.
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3
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Stengel A, Taché Y. Central somatostatin signaling and regulation of food intake. Ann N Y Acad Sci 2019; 1455:98-104. [PMID: 31237362 DOI: 10.1111/nyas.14178] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 12/29/2022]
Abstract
The discovery of somatostatin (SST) in the hypothalamus implicated the peptide in the inhibition of growth hormone release. However, as observed for numerous neuropeptides, SST was neither restricted to this one brain site nor to this one function. Subsequent studies established a widespread but specific expression of SST in the central nervous system of rodents and humans along with the expression patterns of five receptors (sst1-5 ). Among biological actions, the activation of central SST signaling induced a robust stimulation of food and water intake, which is mediated by the sst2 as assessed using selective sst agonists. The past years have witnessed the identification of brain SST circuitries involved using chemogenetic and optogenetic approaches and further established a physiological orexigenic role of brain SST signaling. The present review will discuss these recent findings.
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Affiliation(s)
- Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.,Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany
| | - Yvette Taché
- Department of Medicine, CURE: Digestive Diseases Research Center, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California.,VA Greater Los Angeles Healthcare System, Los Angeles, California
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4
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Ionov ID, Pushinskaya II, Roslavtseva LA, Severtsev NN. Brain sites mediating cyclosomatostatin-induced catalepsy in Wistar rats: A specific role for the nigrostriatal system and locus coeruleus. Brain Res 2018; 1691:26-33. [PMID: 29680272 DOI: 10.1016/j.brainres.2018.04.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 02/05/2023]
Abstract
A decrease in somatostatin activity is observed in the Parkinsonian brain. In recent experiments on rats, we simulated this abnormality by intracerebroventricular injections of a somatostatin antagonist, cyclosomatostatin. The treated animals displayed catalepsy, a state that resembles the extrapyramidal signs of Parkinson's disease. The neuroanatomical substrates mediating the catalepsy-inducing effect of cyclosomatostatin are unknown. To clarify this issue, we assessed here the action of cyclosomatostatin injected into the substantia nigra pars compacta (SNc), dorsal striatum (DS), locus coeruleus (LC), pedunculopontine tegmental nucleus (PPTg), and inferior colliculus (IC). The experiments were conducted with male Wistar rats of 270-290 g bw, catalepsy was evaluated by using the bar test. The injections into the PPTg and IC were without effect whereas the intra-SNc, intra-DS, and intra-LC administrations produced distinct cataleptic response. Thus, it was shown for the first time that the LC is a brain center capable of causing catalepsy. These data provide new insights into the neuroanatomical organization of the catalepsy-initiating mechanism and suggest the LC representing a potential target for therapeutic manipulations of extrapyramidal dysfunctions.
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Affiliation(s)
- Ilya D Ionov
- Centre on Theoretical Problems in Physical and Chemical Pharmacology, Russian Academy of Sciences, Moscow, Russia.
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5
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Stengel A, Karasawa H, Taché Y. The role of brain somatostatin receptor 2 in the regulation of feeding and drinking behavior. Horm Behav 2015; 73:15-22. [PMID: 26026616 PMCID: PMC4546908 DOI: 10.1016/j.yhbeh.2015.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/13/2015] [Accepted: 05/18/2015] [Indexed: 12/13/2022]
Abstract
Somatostatin was discovered four decades ago as hypothalamic factor inhibiting growth hormone release. Subsequently, somatostatin was found to be widely distributed throughout the brain and to exert pleiotropic actions via interaction with five somatostatin receptors (sst1-5) that are also widely expressed throughout the brain. Interestingly, in contrast to the predominantly inhibitory actions of peripheral somatostatin, the activation of brain sst2 signaling by intracerebroventricular injection of stable somatostatin agonists potently stimulates food intake and independently, drinking behavior in rodents. The orexigenic response involves downstream orexin-1, neuropeptide Y1 and μ receptor signaling while the dipsogenic effect is mediated through the activation of the brain angiotensin 1 receptor. Brain sst2 activation is part of mechanisms underlying the stimulation of feeding and more prominently water intake in the dark phase and is able to counteract the anorexic response to visceral stressors.
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Affiliation(s)
- Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Division of General Internal and Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany
| | - Hiroshi Karasawa
- CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women's Health, Department of Medicine, Digestive Diseases Division at the University of California Los Angeles, and VA Greater Los Angeles Health Care System, CA 90073, USA
| | - Yvette Taché
- CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women's Health, Department of Medicine, Digestive Diseases Division at the University of California Los Angeles, and VA Greater Los Angeles Health Care System, CA 90073, USA.
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Stengel A, Rivier J, Taché Y. Central actions of somatostatin-28 and oligosomatostatin agonists to prevent components of the endocrine, autonomic and visceral responses to stress through interaction with different somatostatin receptor subtypes. Curr Pharm Des 2013; 19:98-105. [PMID: 22950508 DOI: 10.2174/13816128130114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 07/30/2012] [Indexed: 01/23/2023]
Abstract
Somatostatin was discovered four decades ago and since then its physiological role has been extensively investigated, first in relation with its inhibitory effect on growth hormone secretion but soon it expanded to extrapituitary actions influencing various stressresponsive systems. Somatostatin is expressed in distinct brain nuclei and binds to five somatostatin receptor subtypes which are also widely expressed in the brain with a distinct distribution pattern. The last few years witnessed the discovery of highly selective peptide somatostatin receptor agonists and antagonists representing valuable tools to delineate the respective pathways of somatostatin signaling. Here we review the centrally mediated actions of somatostatin and related selective somatostatin receptor subtype agonists to influence the endocrine, autonomic, and visceral components of the stress response and basal behavior as well as thermogenesis.
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Affiliation(s)
- Andreas Stengel
- CURE: Digestive Diseases Research Center and Center for Neurovisceral Sciences & Women's Health, Digestive Diseases Division, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
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7
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Stengel A, Coskun T, Goebel-Stengel M, Craft LS, Alsina-Fernandez J, Wang L, Rivier J, Taché Y. Chronic injection of pansomatostatin agonist ODT8-SST differentially modulates food intake and decreases body weight gain in lean and diet-induced obese rats. REGULATORY PEPTIDES 2011; 167:201-8. [PMID: 21315111 PMCID: PMC3717146 DOI: 10.1016/j.regpep.2011.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 12/30/2010] [Accepted: 01/31/2011] [Indexed: 01/21/2023]
Abstract
The aim of this study was to investigate the central actions of the stable pansomatostatin peptide agonist, ODT8-SST on body weight. ODT8-SST or vehicle was acutely (1μg/rat) injected or chronically infused (5μg/rat/d, 14d) intracerebroventricularly and daily food intake, body weight and composition were monitored. In lean rats, neither acute nor chronic ODT8-SST influenced daily food intake while body weight was reduced by 2.2% after acute injection and there was a 14g reduction of body weight gain after 14d compared to vehicle (p<0.01). In diet-induced obese (DIO) rats, chronic ODT8-SST increased cumulative 2-week food intake compared to vehicle (+14%, p<0.05) and also blunted body weight change (-11g, p<0.05). ODT8-SST for 14d reduced lean mass (-22g and -25g respectively, p<0.001) and total water (-19g and -22g respectively, p<0.001) in lean and DIO rats and increased fat mass in DIO (+16g, p<0.001) but not lean rats (+1g, p>0.05) compared to vehicle. In DIO rats, ODT8-SST reduced ambulatory (-27%/24h, p<0.05) and fine movements (-38%, p<0.01) which was associated with an increased positive energy balance compared to vehicle (+50g, p<0.01). Chronic central somatostatin receptor activation in lean rats reduces body weight gain and lean mass independently of food intake which is likely related to growth hormone inhibition. In DIO rats, ODT8-SST reduces lean mass but promotes food intake and fat mass, indicating differential responsiveness to somatostatin under obese conditions.
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Affiliation(s)
- 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
| | - Tamer Coskun
- Biotechnology Discovery Research, Eli Lilly and Company, Indianapolis, IN, USA
| | - Miriam Goebel-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
| | - Libbey S. Craft
- Biotechnology Discovery Research, Eli Lilly and Company, Indianapolis, IN, USA
| | | | - Lixin Wang
- 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
| | - Jean Rivier
- Peptide Biology Laboratories, Salk Institute, La Jolla, CA, USA
| | - 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
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8
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Stengel A, Coskun T, Goebel M, Wang L, Craft L, Alsina-Fernandez J, Rivier J, Taché Y. Central injection of the stable somatostatin analog ODT8-SST induces a somatostatin2 receptor-mediated orexigenic effect: role of neuropeptide Y and opioid signaling pathways in rats. Endocrinology 2010; 151:4224-35. [PMID: 20610566 PMCID: PMC2940496 DOI: 10.1210/en.2010-0195] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Somatostatin and octreotide injected into the brain have been reported to modulate food intake. However, little is known regarding the underlying mechanisms. The stable oligosomatostatin analog, des-AA(1,2,4,5,12,13)-[DTrp(8)]-somatostatin (ODT8-SST), like somatostatin, binds to all five somatostatin receptors (sst(1-5)). We characterized the effects of ODT8-SST injected intracerebroventricularly (i.c.v.) on food consumption and related mechanisms of action in freely fed rats. ODT8-SST (0.3 and 1 microg per rat, i.c.v.) injected during the light or dark phase induced an early onset (within 1 h) and long-lasting (4 h) increase in food intake in nonfasted rats. By contrast, i.p. injection (0.3-3 mg/kg) or i.c.v. injection of selective sst(1) or sst(4) agonists (1 microg per rat) had no effect. The 2 h food intake response during the light phase was blocked by i.c.v. injection of a sst(2) antagonist, the neuropeptide Y (NPY) Y(1) receptor antagonist, BIBP-3226, and ip injection of the mu-opioid receptor antagonist, naloxone, and not associated with changes in plasma ghrelin levels. ODT8-SST (1 microg per rat, i.c.v.) stimulated gastric emptying of a solid meal which was also blocked by naloxone. The increased food intake was accompanied by a sustained increase in respiratory quotient, energy expenditure, and drinking as well as mu-opioid receptor-independent grooming behavior and hyperthermia, while ambulatory movements were not altered after ODT8-SST (1 microg per rat, i.c.v.). These data show that ODT8-SST acts primarily through brain sst(2) receptors to induce a long-lasting orexigenic effect that involves the activation of Y(1) and opiate-receptors, accompanied by enhanced gastric transit and energy expenditure suggesting a modulation of NPYergic and opioidergic orexigenic systems by brain sst(2) receptors.
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MESH Headings
- Animals
- Anti-Anxiety Agents/administration & dosage
- Anti-Anxiety Agents/pharmacology
- Arginine/administration & dosage
- Arginine/analogs & derivatives
- Arginine/pharmacology
- Body Temperature/drug effects
- Eating/drug effects
- Eating/physiology
- Energy Metabolism/drug effects
- Gastric Emptying/drug effects
- Grooming/drug effects
- Injections, Intraperitoneal
- Injections, Intraventricular
- Male
- Mice
- Mice, Inbred C57BL
- Naloxone/administration & dosage
- Naloxone/pharmacology
- Peptide Fragments/administration & dosage
- Peptide Fragments/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Neuropeptide Y/antagonists & inhibitors
- Receptors, Neuropeptide Y/physiology
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/physiology
- Receptors, Somatostatin/agonists
- Receptors, Somatostatin/antagonists & inhibitors
- Receptors, Somatostatin/physiology
- Somatostatin/administration & dosage
- Somatostatin/analogs & derivatives
- Somatostatin/pharmacology
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Affiliation(s)
- Andreas Stengel
- Department of Medicine, Center for Ulcer Research and Education, Digestive Diseases Division, University of California Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, USA
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9
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Rollo CD, Lai M, Whitehead K, Perreault ML, Lemon J, Chaudhry AM. Thermoregulation of transgenic growth hormone mice. CAN J ZOOL 2004. [DOI: 10.1139/z04-052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Transgenic growth hormone (TG) mice (Mus musculus L., 1758) obtain enhanced growth via compensatory feeding at intermediate sizes and via higher growth efficiency. The latter involves diverting resources from other functions such as locomotion and wakefulness. Thermogenesis is a major expense for small mammals, so we explored whether TG mice express a trade-off between growth and thermoregulation. TG mice are hypothermic and cannot maintain their body temperature under cold stress. TG mice showed initial enlargement of brown adipose tissue and subsequent age-related decreases not seen in controls. Some TG mice became torpid after fasting durations not known to affect other mice. On a high-calorie diet, TG mice had higher body temperatures even though controls did not. Our background strain developed obesity on a high-protein and high-fat diet, and on a diet supplemented with carbohydrates, whereas TG mice never developed obesity. White adipose tissue deposits of TG females were relatively larger, but those of TG males were relatively smaller, than those of controls fed standard food. We also found significant effects of the three experimental diets, as well as gender, age, body mass, ambient temperature, and behavioural activity, on rectal temperatures of TG mice and controls in a large breeding colony. Thermogenesis of TG mice fed standard food appears energetically constrained, likely contributing to enhanced growth efficiency.
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10
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Scalera G. Peptides that regulate food intake: somatostatin alters intake of amino acid-imbalanced diets and taste buds of tongue in rats. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1389-98. [PMID: 12736176 DOI: 10.1152/ajpregu.00738.2002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present studies were designed to evaluate a potential dose-dependent effect of somatostatin (SRIF) administered peripherally on intake of either a low-protein basal diet or threonine-imbalanced diet (THR-IMB), on body weight gain (DeltaBW), gut motility, and on the histology of taste buds in rats. SRIF administration had a dual effect related to its concentration, increasing the intake of THR-IMB diet at low concentration and decreasing THR-IMB diet at high concentration. During the light phase, SRIF treatment increased the intake of THR-IMB diet, suggesting that the usual anorectic effect induced by intake of THR-IMB diet was attenuated. High-dosage SRIF decreases gastrointestinal motility, which, in turn, can decrease food intake and DeltaBW. The combination of THR-IMB diet regimen and SRIF treatment also induced significant modifications on the taste buds of the tongue. The feeding response to an amino acid-imbalanced diet includes a learned aversion to the diet, and animals may use taste in establishing that aversion. Modifications of taste buds of SRIF-treated rats eating THR-IMB diet might explain the increase of imbalanced diet intake if treated rats perceive this food as less aversive.
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Affiliation(s)
- Giuseppe Scalera
- Dipartimento di Scienze Biomediche, Sezione di Fisiologia, Università di Modena e Reggio Emilia, 41100 Modena, Italy.
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11
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Ingvartsen KL, Andersen JB. Integration of metabolism and intake regulation: a review focusing on periparturient animals. J Dairy Sci 2000; 83:1573-97. [PMID: 10908064 DOI: 10.3168/jds.s0022-0302(00)75029-6] [Citation(s) in RCA: 345] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
There has been great interest in dry matter intake regulation in lactating dairy cattle to enhance performance and improve animal health and welfare. Predicting voluntary dry matter intake (VDMI) is complex and influenced by numerous factors relating to the diet, management, housing, environment and the animal. The objective of this review is to identify and discuss important metabolic factors involved in the regulation of VDMI and their integration with metabolism. We have described the adaptations of intake and metabolism and discussed mechanisms of intake regulation. Furthermore we have reviewed selected metabolic signals involved in intake regulation. A substantial dip in VDMI is initiated in late pregnancy and continues into early lactation. This dip has traditionally been interpreted as caused by physical constraints, but this role is most likely overemphasized. The dip in intake coincides with changes in reproductive status, fat mass, and metabolic changes in support of lactation, and we have described metabolic signals that may play an equally important role in intake regulation. These signals include nutrients, metabolites, reproductive hormones, stress hormones, leptin, insulin, gut peptides, cytokines, and neuropeptides such as neuropeptide Y, galanin, and corticotrophin-releasing factor. The involvement of these signals in the periparturient dip in intake is discussed, and evidence supporting the integration of the regulation of intake and metabolism is presented. Still, much research is needed to clarify the complex regulation of VDMI in lactating dairy cows, particularly in the periparturient animal.
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Affiliation(s)
- K L Ingvartsen
- Danish Institute of Agricultural Sciences, Department of Animal Health and Welfare, Research Centre Foulum, Tjele.
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12
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Rollo CD, Ko CV, Tyerman JGA, Kajiura LJ. The growth hormone axis and cognition: empirical results and integrated theory derived from giant transgenic mice. CAN J ZOOL 1999. [DOI: 10.1139/z99-153] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sleep is required for the consolidation of memory for complex tasks, and elements of the growth-hormone (GH) axis may regulate sleep. The GH axis also up-regulates protein synthesis, which is required for memory consolidation. Transgenic rat GH mice (TRGHM) express plasma GH at levels 100-300 times normal and sleep 3.4 h longer (30%) than their normal siblings. Consequently, we hypothesized that they might show superior ability to learn a complex task (8-choice radial maze); 47% of the TRGHM learned the task before any normal mice. All 17 TRGHM learned the task, but 33% of the 18 normal mice learned little. TRGHM learned the task significantly faster than normal mice (p < 0.05) and made half as many errors in doing so, even when the normal nonlearners were excluded from the analysis. Whereas normal mice expressed a linear learning curve, TRGHM showed exponentially declining error rates. The contribution of the GH axis to cognition is conspicuously sparse in literature syntheses of knowledge concerning neuroendocrine mechanisms of learning and memory. This paper synthesizes the crucial role of major components of the GH axis in brain functioning into a holistic framework, integrating learning, sleep, free radicals, aging, and neurodegenerative diseases. TRGHM show both enhanced learning in youth and accelerated aging. Thus, they may provide a powerful new probe for use in gaining an understanding of aspects of central nervous system functioning, which is highly relevant to human health.
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13
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Rollo CD, Kajiura LJ, Wylie B, D'Souza S. The growth hormone axis, feeding, and central allocative regulation: lessons from giant transgenic growth hormone mice. CAN J ZOOL 1999. [DOI: 10.1139/z99-162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Lifetime consumption rates of male transgenic growth hormone (GH) mice and normal controls were measured on either a 38% protein diet (HP), the standard rodent diet (STD) (23.5% protein), or the standard diet supplemented with a free choice of sucrose (CARB). On STD, daily intake of normal mice increased little at sizes greater than 20 g, but larger transgenic mice ate progressively more. Both kinds of mice showed declining daily mass-specific consumption with increasing age. Transgenic mice consistently ate 13.3% less food than normal mice on a mass-specific basis across all ages. On the self-selective CARB diet, normal mice exhibited increasing age-specific daily consumption, whereas transgenic mice exhibited a trend towards age-related decline in mass-specific feeding that proved significant on the basis of body mass. Transgenic mice ingested more sucrose than standard chow and this did not vary with age. In contrast, normal mice ate less sucrose than chow and chose a declining proportion of sucrose with age. Transgenic and normal mice showed a unitary relationship of daily intake of HP in relation to body mass, resulting in constant mass-specific feeding across all ages. Transgenic GH animals, including livestock, show numerous defects that we have attributed to relative energetic stress associated with excessive allocation to lean growth. This is exacerbated by failure to offset increased demands of growth by increasing mass-specific feeding. Results presented here document altered feeding regulation in transgenic GH mice and suggest underlying mechanisms.
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14
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Abstract
The effects of a long period of relatively high and nearly constant levels of Somatostatin (SRIF) on the control of food ingestion and body weight gain were investigated; weight gain occurs via concurrent modifications of food and fluid intake and in vitro gut motility. Fluid intake was not influenced by SRIF treatment. Food intake, body weight, body weight gain, and gut motility decreased after SRIF treatment, and, in some cases, these effects were dose-dependent. Food intake increased significantly during light phase of SRIF treatment. Thus, SRIF treatment produces facilitation of food intake in the light and inhibition in the dark. The suppression seen in the dark may be the result of a preferential activation of the inhibitory response. The increase of food intake during the light may be explained by a decreased availability of body fats as fuels for metabolism since SRIF inhibits GH release, which is involved is the breakdown of adipose tissue into fuels; lower fats synthesis during nocturnal feeding; or both. Decreased gastrointestinal motility also may explain the lower food intake and decreased body weight gain following SRIF treatment.
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Affiliation(s)
- G Scalera
- Dipartimento di Scienze Biomediche, Università di Modena, Italy.
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15
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Ingvartsen KL, Sejrsen K. Effect of Immunization against Somatostatin (SS) in Cattle: A Review of Performance, Carcass Composition and Possible Mode of Action. ACTA AGR SCAND A-AN 1995. [DOI: 10.1080/09064709509415840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Feifel D, Vaccarino FJ. Growth hormone-regulatory peptides (GHRH and somatostatin) and feeding: a model for the integration of central and peripheral function. Neurosci Biobehav Rev 1994; 18:421-33. [PMID: 7984360 DOI: 10.1016/0149-7634(94)90055-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The present paper provides an overview of findings that implicate growth hormone-releasing hormone (GHRH) and somatostatin (SS), the two peptides that regulate growth hormone secretion, in the central regulation of feeding. Evidence is presented that GHRH and SS increase food intake, in the rat, via a common centrally mediated mechanism involving the suprachiasmatic nucleus. Food intake is increased by increasing motivation to eat as evidenced by facilitation of operant behavior. Macronutrient-choice studies indicate that GHRH (and possibly SS) selectively facilitate protein consumption. Time of day is also important, with evidence that endogenous GHRH and SS-induced feeding is most strong in the early nocturnal period. GHRH and SS, together with other nutrient-specific signals, such as neuropeptide Y, noradrenaline and galanin, may determine the circadian expression of food intake in animals. Other behavioral and physiological effects of these peptides, both central and peripheral, are reviewed in the context of a possible mechanism by which these peptides integrate diverse, but complimentary, central and peripheral functions related to nutrition, metabolism and growth.
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Affiliation(s)
- D Feifel
- Department of Psychiatry, University of California, San Diego, La Jolla 92093
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17
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Ingvartsen KL, Andersen HR. Space Allowance and Type of Housing for Growing Cattle: A Review of Performance and Possible Relation to Neuroendocrine Function. ACTA AGR SCAND A-AN 1993. [DOI: 10.1080/09064709309410147] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Lin SS, Chan JY, Chan SH. Facilitation of baroreceptor reflex response by endogenous somatostatin in the rat. REGULATORY PEPTIDES 1991; 33:239-50. [PMID: 1679245 DOI: 10.1016/0167-0115(91)90227-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We evaluated the potential participation of endogenous brain somatostatin-14 (SOM) in central cardiovascular regulation, using adult male Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p.). Intracerebroventricular (i.c.v.) application of SOM (2 or 4 nmol) promoted a significant elevation in baroreceptor reflex (BRR) response, induced by phenylephrine (5 micrograms kg, i.v.). Blocking the endogenous SOM activity with its specific receptor antagonist, cyclo-[7-aminoheptanoyl-Phe-D-Trp-Lys-Thr(Bzl)] (2 or 4 nmol, i.c.v.) or antiserum against SOM (1:20, i.c.v.), on the other hand, appreciably attenuated the same response. These modulatory effects on the BRR response were essentially duplicated upon bilateral microinjections of SOM (320 pmol), SOM antagonist (320 pmol) or anti-SOM (1:20) into the caudal portion of the nucleus of tractus solitarius (NTS), the terminal site for baroreceptor afferents. These results suggest that neurons that contain SOM may participate in cardiovascular control by tonically facilitating the BRR, possibly by exerting an influence on the neurons at the NTS.
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Affiliation(s)
- S S Lin
- Institute of Pharmacology, National Yang-Ming Medical College, Taipei, Taiwan, Republic of China
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19
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Abstract
Previous investigations of centrally administered somatostatin (SRIF) have tended to employ pharmacological (nmol and greater) doses of the peptide. Under this protocol contradictory findings of feeding effects have been reported. There is evidence that the use of physiological doses can induce a completely distinct response from that obtained with pharmacological doses. In order to discern whether physiological doses of centrally administered somatostatin have any effect on feeding. SRIF in doses ranging from 0.4 pmol to 3 nmol were administered into the lateral ventricles of rats. Low pmol doses (0.4-40) administered during the light photoperiod increased 1 h feeding whereas 3 nmol decreased 1 h feeding. None of the doses tested during the dark photoperiod significantly altered 1 h food intake. Similarly, no significant change in 24-h food intake was observed following injections of any of the doses tested, whether in the light or dark. A dose of SRIF that increased feeding (1 pmol) did not significantly alter 1 h water intake when applied centrally in the light nor did it alter spontaneous locomotor activity. Furthermore, when applied peripherally it did not change 1 h food intake. These studies suggest that SRIF may work centrally to regulate food intake. A similarity exists between SRIF's feeding effects and the feeding effects we have previously described following central injections of growth hormone-releasing factor (GRF), both in terms of dose-response and photosensitivity. This suggests that these 2 peptides may act via a common mechanism to regulate food consumption; possibly in co-ordination with their regulation of growth hormone release. The possibility that such feeding regulation occurs as part of a short intrahypothalamic feedback loop is discussed.
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Marcinkiewicz M, Morcos R, Chrétien M. CNS connections with the median raphe nucleus: retrograde tracing with WGA-apoHRP-Gold complex in the rat. J Comp Neurol 1989; 289:11-35. [PMID: 2478595 DOI: 10.1002/cne.902890103] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this work we examined the neuronal input to one of the serotoninergic centers in the brain, median raphe nucleus (MR). Special consideration is given to projections of the hypothalamus. To describe the afferents to MR, a retrograde transport technique was used after microinjection of WGA-apoHRP-Gold complex under pressure and subsequent gold-silver intensification on formaldehyde-fixed rat brain sections. Optimal conditions were obtained when the coordinates of the injection site were A +/- 1.5, L +/- 0.15, and H +/- 2.7 according to Paxinos and Watson (The Rat Brain in Stereotaxic Coordinates. New York: Academic Press, '82). Results obtained under these conditions show a heterogeneous distribution of labeled neurons throughout the brain, including a large proportion (+/- 65%) of hypothalamic neurons. Extra-hypothalamic neurons projecting to MR were from the prefrontal cortex, lateral and medial habenular nuclei, the pontine area of the central grey, interpeduncular nucleus, dorsal raphe nucleus, oculomotor and trochlear nuclei, dorsal and laterodorsal tegmental nuclei, parabrachial nuclei, and lateral and interpositus cerebellar nuclei. Hypothalamic neurons connected to MR were found to be from medial and lateral preoptic areas, lateral hypothalamus, dorsomedian nucleus, the perifornical area, and the complex of mammillary bodies. Many other discrete regions contained different densities of labeled perikarya: the medial preoptic nucleus, paraventricular nucleus, retrochiasmatic area, arcuate nucleus, lateral magnocellular nucleus, and the posterior area. The MR appears as an integrative center receiving many neuroanatomically and functionally heterogeneous inputs from the whole brain.
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Affiliation(s)
- M Marcinkiewicz
- J.A. De Sève Laboratories of Biochemical and Molecular Neuroendocrinology, Clinical Research Institute of Montreal, Quebec, Canada
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21
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Affiliation(s)
- G Williams
- Department of Medicine, University of Liverpool, UK
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22
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Bobbioni-Harsch E, Jeanrenaud B. The hypothalamic origin of an insulin secretion promoting factor present in the plasma of normal rats. J Neuroendocrinol 1989; 1:103-8. [PMID: 19210466 DOI: 10.1111/j.1365-2826.1989.tb00087.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Abstract Hypothalamic and plasma extracts from normal rats both contain a factor whose property is to stimulate insulin secretion. The two factors have many characteristics in common. Both are active in vivo (when administered to normal recipient rats) and in vitro (when infused into perfused rat pancreases). Both are inactivated by HCI hydrolysis. Both elute at the same ratio between elution volume of the peaks and void volume after gel-chromatographies are carried out, first on Sephadex G-50, then on Biogel P-2, indicating that they have a similar molecular weight which ranges between 800 and 1,200 Daltons. When anaesthetized rats are submitted to an acute bilateral electrical stimulation of the lateral hypothalamus, the insulin secretion stimulating activity present in the plasma is enhanced compared to that measured in sham-stimulated control rats. Conversely, the insulin secretion promoting activity is decreased in plasma from rats whose ventral hypothalamus is acutely and electrolytically lesioned. These data indicate that, in normal rats, the hypothalamus contains an insulin secretion promoting factor that is releasable in the plasma.
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Affiliation(s)
- E Bobbioni-Harsch
- Laboratoires de Recherches Métaboliques, Faculty and Department of Medicine, Geneva University, Avenue de la Roseraie 64, 1211 Geneva 4, Switzerland
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Ho LT, Chern YF, Lin MT. The hypothalamic somatostatinergic pathways mediate feeding behavior in the rat. EXPERIENTIA 1989; 45:161-2. [PMID: 2563980 DOI: 10.1007/bf01954859] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The level of somatostatin in the hypothalamus was higher in satiated rats than in hungry rats. Elevating hypothalamic somatostatin levels by administering somatostatin into the hypothalamus produced a decrease in food intake, whereas lowering hypothalamic somatostatin levels by administering cysteamine into the peritoneal cavity produced an increase in food intake in rats.
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Affiliation(s)
- L T Ho
- Department of Internal Medicine, Veterans General Hospital, Taipei, Taiwan
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