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Alemany M. The Metabolic Syndrome, a Human Disease. Int J Mol Sci 2024; 25:2251. [PMID: 38396928 PMCID: PMC10888680 DOI: 10.3390/ijms25042251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/29/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.
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Affiliation(s)
- Marià Alemany
- Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain
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Flees J, Greene E, Ganguly B, Dridi S. Phytogenic feed- and water-additives improve feed efficiency in broilers via modulation of (an)orexigenic hypothalamic neuropeptide expression. Neuropeptides 2020; 81:102005. [PMID: 31926603 DOI: 10.1016/j.npep.2020.102005] [Citation(s) in RCA: 5] [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: 10/14/2019] [Revised: 12/17/2019] [Accepted: 01/02/2020] [Indexed: 12/12/2022]
Abstract
Fueled by consumer preference for natural and antibiotic-free products, phytogenics have become the fastest growing segment of the animal feed additives. Yet, their modes of action are not fully understood. This study was undertaken to determine the effect of 5 phytogenics (3 feed- and 2 water-supplements) on the growth performance of commercial broilers, and their potential underlying molecular mechanisms. Day-old male Cobb 500 chicks (n = 576) were randomly assigned into 48 pens consisting of 6 treatments (Control; AVHGP; SCP; BHGP; AVSSL; SG) in a complete randomized design (12 birds/pen, 8 pens/treatment, 96 birds/treatment). Chicks had ad libitum access to feed and water. Individual body weight (BW) was recorded weekly and feed intake was measured daily. Core body temperatures were continuously recorded using thermo-loggers. At d 35, hypothalamic tissues were excised from the thermo-logger-equipped chickens (n = 8 birds/treatment) to determine the expression of feeding-related neuropeptides. Both feed (AVHGP, SCP, BHGP) and water-supplemented (AVSSL, SG) phytogenics significantly improved feed efficiency (FE) compared to the control birds. This higher FE was achieved via a reduction in core body temperature and improvement of market BW, without changes in feed intake in broilers supplemented with phytogenic water additives as compared to the control group. Broilers fed dietary phytogenics, however, attained higher feed efficiency via a reduction in feed intake while maintaining similar BW as the control group. At the molecular levels, the effects of the phytogenic water additives seemed to be mediated by the activation of the hypothalamic AgRP-ORX-mTOR-S6k1 and inhibition of CRH pathways. The effect of the phytogenic feed additives appeared to be exerted through the activation of AdipoQ, STAT3, AMPK, and MC1R pathways. This is the first report describing the likely central mechanisms through which phytogenic additives improve the growth performance and feed efficiency in broilers.
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Affiliation(s)
- Joshua Flees
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States of America
| | - Elizabeth Greene
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States of America
| | - Bhaskar Ganguly
- Clinical Research, Ayurvet Limited, Baddi, Himachal Pradesh 173205, India
| | - Sami Dridi
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, United States of America.
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MacCormack JK, Muscatell KA. The metabolic mind: A role for leptin and ghrelin in affect and social cognition. SOCIAL AND PERSONALITY PSYCHOLOGY COMPASS 2019. [DOI: 10.1111/spc3.12496] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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4
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Hill JW, Elias CF. Neuroanatomical Framework of the Metabolic Control of Reproduction. Physiol Rev 2019; 98:2349-2380. [PMID: 30109817 DOI: 10.1152/physrev.00033.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A minimum amount of energy is required for basic physiological processes, such as protein biosynthesis, thermoregulation, locomotion, cardiovascular function, and digestion. However, for reproductive function and survival of the species, extra energy stores are necessary. Production of sex hormones and gametes, pubertal development, pregnancy, lactation, and parental care all require energy reserves. Thus the physiological systems that control energy homeostasis and reproductive function coevolved in mammals to support both individual health and species subsistence. In this review, we aim to gather scientific knowledge produced by laboratories around the world on the role of the brain in integrating metabolism and reproduction. We describe essential neuronal networks, highlighting key nodes and potential downstream targets. Novel animal models and genetic tools have produced substantial advances, but critical gaps remain. In times of soaring worldwide obesity and metabolic dysfunction, understanding the mechanisms by which metabolic stress alters reproductive physiology has become crucial for human health.
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Affiliation(s)
- Jennifer W Hill
- Center for Diabetes and Endocrine Research, Departments of Physiology and Pharmacology and of Obstetrics and Gynecology, University of Toledo College of Medicine , Toledo, Ohio ; and Departments of Molecular and Integrative Physiology and of Obstetrics and Gynecology, University of Michigan , Ann Arbor, Michigan
| | - Carol F Elias
- Center for Diabetes and Endocrine Research, Departments of Physiology and Pharmacology and of Obstetrics and Gynecology, University of Toledo College of Medicine , Toledo, Ohio ; and Departments of Molecular and Integrative Physiology and of Obstetrics and Gynecology, University of Michigan , Ann Arbor, Michigan
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Celik O, Aydin S, Celik N, Yilmaz M. Peptides: Basic determinants of reproductive functions. Peptides 2015; 72:34-43. [PMID: 26074346 DOI: 10.1016/j.peptides.2015.05.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 12/22/2022]
Abstract
Mammalian reproduction is a costly process in terms of energy consumption. The critical information regarding metabolic status is signaled to the hypothalamus mainly through peripheral peptides from the adipose tissue and gastrointestinal tract. Changes in energy stores produce fluctuations in leptin, insulin, ghrelin and glucose signals that feedback mainly to the hypothalamus to regulate metabolism and fertility. In near future, possible effects of the nutritional status on GnRH regulation can be evaluated by measuring serum or tissue levels of leptin and ghrelin in patiens suffering from infertility. The fact that leptin and ghrelin are antagonistic in their effects on GnRH neurons, their respective agonistic and antagonistic roles make them ideal candidates to use instead of GnRH agonist and antagonist. Similarly, kisspeptin expressing neurons are likely to mediate the well-established link between energy balance and reproductive functions. Exogenous kisspeptin can be used for physiological ovarian hyperstimulation for in-vitro fertilization. Moreover, kisspeptin antagonist therapy can be used for the treatment of postmenapousal women, precocious puberty, PCOS, endometriosis and uterine fibroids. In this review, we will analyze the central mechanisms involved in the integration of metabolic information and their contribution to the control of the reproductive function. Particular attention will be paid to summarize the participation of leptin, kisspeptin, ghrelin, NPY, orexin, urocortin, VIP, insulin, galanin, galanin like peptide, oxytocin, agouti gene-related peptide, and POMC neurons in this process and their possible interactions to contribute to the metabolic control of reproduction.
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Affiliation(s)
- Onder Celik
- Private Clinic, Department of Obstetrics and Gynecology, İzmir, Turkey
| | - Suleyman Aydin
- Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormones Research Group), 23119 Elazig, Turkey.
| | - Nilufer Celik
- Behcet Uz Children's Hospital, Department of Biochemistry, İzmir, Turkey
| | - Musa Yilmaz
- Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormones Research Group), 23119 Elazig, Turkey
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Yu YH, Vasselli JR, Zhang Y, Mechanick JI, Korner J, Peterli R. Metabolic vs. hedonic obesity: a conceptual distinction and its clinical implications. Obes Rev 2015; 16:234-47. [PMID: 25588316 PMCID: PMC5053237 DOI: 10.1111/obr.12246] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 11/19/2014] [Accepted: 11/19/2014] [Indexed: 01/01/2023]
Abstract
Body weight is determined via both metabolic and hedonic mechanisms. Metabolic regulation of body weight centres around the 'body weight set point', which is programmed by energy balance circuitry in the hypothalamus and other specific brain regions. The metabolic body weight set point has a genetic basis, but exposure to an obesogenic environment may elicit allostatic responses and upward drift of the set point, leading to a higher maintained body weight. However, an elevated steady-state body weight may also be achieved without an alteration of the metabolic set point, via sustained hedonic over-eating, which is governed by the reward system of the brain and can override homeostatic metabolic signals. While hedonic signals are potent influences in determining food intake, metabolic regulation involves the active control of both food intake and energy expenditure. When overweight is due to elevation of the metabolic set point ('metabolic obesity'), energy expenditure theoretically falls onto the standard energy-mass regression line. In contrast, when a steady-state weight is above the metabolic set point due to hedonic over-eating ('hedonic obesity'), a persistent compensatory increase in energy expenditure per unit metabolic mass may be demonstrable. Recognition of the two types of obesity may lead to more effective treatment and prevention of obesity.
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Affiliation(s)
- Y-H Yu
- Weight Loss and Diabetes Center, Greenwich Hospital, Greenwich, CT, USA; Endocrinology Associates of Greenwich, Northeast Medical Group, Yale New-Haven Health System, Greenwich, CT, USA
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MacLean PS, Higgins JA, Giles ED, Sherk VD, Jackman MR. The role for adipose tissue in weight regain after weight loss. Obes Rev 2015; 16 Suppl 1:45-54. [PMID: 25614203 PMCID: PMC4371661 DOI: 10.1111/obr.12255] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Weight regain after weight loss is a substantial challenge in obesity therapeutics. Dieting leads to significant adaptations in the homeostatic system that controls body weight, which promotes overeating and the relapse to obesity. In this review, we focus specifically on the adaptations in white adipose tissues that contribute to the biological drive to regain weight after weight loss. Weight loss leads to a reduction in size of adipocytes and this decline in size alters their metabolic and inflammatory characteristics in a manner that facilitates the clearance and storage of ingested energy. We present the hypothesis whereby the long-term signals reflecting stored energy and short-term signals reflecting nutrient availability are derived from the cellularity characteristics of adipose tissues. These signals are received and integrated in the hypothalamus and hindbrain and an energy gap between appetite and metabolic requirements emerges and promotes a positive energy imbalance and weight regain. In this paradigm, the cellularity and metabolic characteristics of adipose tissues after energy-restricted weight loss could explain the persistence of a biological drive to regain weight during both weight maintenance and the dynamic period of weight regain.
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Affiliation(s)
- P S MacLean
- Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, Anschutz Health and Wellness Center, University of Colorado School of Medicine, Aurora, Colorado USA
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Jiao JT, Jiang C, Huang J, Dai MC, Wang C, Cheng C, Shao JF. Metabolic syndrome factors and risk of postoperative depression in high-grade glioma patients in a 1.5-year prospective study. Med Oncol 2014; 31:234. [PMID: 25223530 DOI: 10.1007/s12032-014-0234-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022]
Abstract
To date, the relationship between metabolic syndrome factors and the risk of glioma-related depression is still unclear, and no study investigates this relationship. Our aim was to investigate the relationship between metabolic syndrome factors and the risk of postoperative depression in high-grade patients. A total of 386 high-grade glioma patients participated in blood sample collection for metabolic syndrome factors analysis and the hospital anxiety and depression scale testing. The association between metabolic syndrome factors and the risk of postoperative depression was assessed using Cox regression proportional hazards models, and Student's t tests were used to evaluate the differences in demographic variables and clinical characteristics in subgroups. The incidence of postoperative depression in our 1.5-year follow-up was 30.5%. We found the risk of postoperative depression was elevated with increased blood glucose level [hazard ratios (HR) 2.277, 95% confidence interval (CI) 1.201-4.320, top vs. bottom quartile]. The hazard ratio was increased for z-scores of blood glucose (HR 1.672 per unit standard deviation, 95% CI 1.311-2.133] and of the combined metabolic syndrome score (HR 1.080, 95% CI 1.000-1.167). In addition, risk of postoperative depression risk was increased in high-grade glioma patients with high blood glucose levels (≥6.0 mmol/l) (HR 2.084, 95% CI 1.235-3.515). However, we did not find significant associations between postoperative depression and other metabolic syndrome factors, including body mass index, systolic blood pressure, diastolic blood pressure, cholesterol, and triglycerides. Depression is prevalent among patients with high-grade glioma after operation. Blood glucose level is positively associated with the risk of postoperative depression, and might be involved in the etiology of postoperative depression, and may predict its development in high-grade glioma patients.
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Affiliation(s)
- Jian-Tong Jiao
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Chen Jiang
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Jin Huang
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Min-Chao Dai
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Cheng Wang
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Chao Cheng
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China
| | - Jun-Fei Shao
- Department of Neurosurgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, 214023, China.
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Hirahatake KM, Slavin JL, Maki KC, Adams SH. Associations between dairy foods, diabetes, and metabolic health: potential mechanisms and future directions. Metabolism 2014; 63:618-27. [PMID: 24636056 PMCID: PMC5367265 DOI: 10.1016/j.metabol.2014.02.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 12/14/2022]
Abstract
Epidemiological evidence supports an inverse relationship between adequate intake of dairy foods and susceptibility to type 2 diabetes (T2D). The biological mechanisms responsible for this association remain to be established. This review provides a current perspective on proposed mechanisms that may underlie these effects, and highlights how randomized clinical trials can be applied to investigate these relationships. Results from epidemiological studies generally support that consumption of milk and dairy products is associated with a lower incidence of T2D or improvements in glucose homeostasis indices, and studies of animal and cell models support a positive effect of dairy-rich diets or components on metabolic and inflammation factors relevant to T2D and insulin resistance. Emerging evidence indicates that dairy components that alter mitochondrial function (e.g., leucine actions on silent information regulator transcript 1 (SIRT1)-associated pathways), promote gut microbial population shifts, or influence inflammation and cardiovascular function (e.g., Ca-regulated peptides calcitonin gene-related peptide [CGRP] or calcitonin) should be considered as possible mechanistic factors linking dairy intake with lower risk for T2D. The possibility that dairy-derived trans-palmitoleic acid (tC16:1) has metabolic bioactivities has also been proposed. Pre-clinical and clinical studies focusing specifically on these parameters are needed to validate hypotheses regarding the potential roles of dairy products and their components on the determinants of glucose tolerance, particularly insulin sensitivity, pancreatic endocrine function, and inflammation in individuals at-risk for T2D development. Such experiments would complement epidemiological studies and add to the evidence base for recommendations regarding consumption of dairy products and their individual components.
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Affiliation(s)
- Kristin M Hirahatake
- Obesity & Metabolism Research Unit, USDA-ARS Western Human Nutrition Research Center, Davis, CA
| | - Joanne L Slavin
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN
| | | | - Sean H Adams
- Obesity & Metabolism Research Unit, USDA-ARS Western Human Nutrition Research Center, Davis, CA; Department of Nutrition, University of California, Davis, CA.
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Rhie YJ. Kisspeptin/G protein-coupled receptor-54 system as an essential gatekeeper of pubertal development. Ann Pediatr Endocrinol Metab 2013; 18:55-9. [PMID: 24904852 PMCID: PMC4027097 DOI: 10.6065/apem.2013.18.2.55] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 06/13/2013] [Indexed: 11/30/2022] Open
Abstract
Puberty is the end-point of a complex series of developmental events, defined by the dynamic interaction between genetic factors and environmental cues, ultimately leading to the attainment of reproductive capacity. Kisspeptins, products of the KISS1 gene, were originally identified as metastasis suppressor peptides with the ability to bind G protein-coupled receptors (GPR54). In 2003, loss-of-function mutations of the GPR54 gene were found in patients with hypogonadotropic hypogonadism. This finding triggered study of the role of the kisspeptin/GPR54 system as an essential gatekeeper of control of reproduction and pubertal development. Kisspeptins are very potent elicitors of gonadotropin secretion, primarily through stimulation of gonadotropin-releasing hormone release. KISS1 also functions as an essential integrator for peripheral inputs, including gonadal steroids and nutritional signals, and for controlling GnRH and gonadotropin secretion. Whether the kisspeptin/GPR54 system is the trigger for puberty onset and/or it operates as integrator and effector of up-stream regulatory factors warrants further investigation.
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Affiliation(s)
- Young-Jun Rhie
- Department of Pediatrics, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea
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Appetite control and gastrointestinal hormonal behavior (CCK, GLP-1, PYY 1-36) following low doses of a whey protein-rich nutraceutic. MEDITERRANEAN JOURNAL OF NUTRITION AND METABOLISM 2013; 6:259-266. [PMID: 24319546 PMCID: PMC3851799 DOI: 10.1007/s12349-013-0121-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 01/04/2013] [Indexed: 12/12/2022]
Abstract
Whey proteins represent the most satiating nutrients. In particular, their effects are due to enterohormonal changes (CCK, GLP-1 and PYY 1–36) observed after their exclusive ingestion. Glucomannan has important satiety property due to volume increase following gelification. The aim of the study is the evaluation of subjective rate of hunger and enterohormone concentrations (CCK, GLP-1, PYY 1–36) following oral loading of a mixture containing WP (8 g) or casein (8 g) plus glucomannan (1 g) (Colordiet®, Inpha DUEMILA Srl Lecco, Italy). The study was conducted as a double-blind crossover with five healthy volunteers (BMI 22–26 kg/m2 aging 18–65 years) in acute and a wash-out period of 1 week between the first and the second evaluation. From the analysis of the data, we observe that the load with WP induces a significant decrease in the desire to eat after 90 min (P < 0.0446) when compared with casein. As far as plasma hormones are concerned, there was a significant increase only in GLP-1 at 90 min after WP (P < 0.00166) and 180 min after casein (T0 vs. T180 P = 0.000129). There is a significant correlation between the increase in GLP-1 and decrease of desire to eat (R = −0.93). There is a tendency to the increasing of CCK after 90 min, which is not significant (P = 0.091). These results could be due to (a) the low number of cases or (b) the low dose of protein used. The present study suggests that a mixture of WP plus glucomannan exerts a decrease in the desire to eat which is correlated to enterohormonal modification (GLP-1 increase) despite the low content of protein (8 g) and the presence of glucomannan, which could reduce the fast absorption of WP in relation to the net forming during the gelification of the gastric environment.
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Expression changes of hypothalamic Ahi1 in mice brain: implication in sensing insulin signaling. Mol Biol Rep 2012; 39:9697-705. [PMID: 22740139 DOI: 10.1007/s11033-012-1834-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 06/10/2012] [Indexed: 10/28/2022]
Abstract
Growing evidence suggests that the brain, in particular the hypothalamus, directly senses hormones and nutrients to initiate feeding behavior and metabolic responses in the control of energy homeostasis. However, the molecular mechanisms underlying this important process have remained largely unknown. Our study provides the evidence for the role of Abelson helper integration site 1 (Ahi1) protein as a sensor of insulin signaling in the hypothalamus. We found that fasting increased the expression of hypothalamic Ahi1 which was accompanied by lower levels of circulating insulin compared with satiated mice, while re-feeding decreased the expression of hypothalamic Ahi1 which was accompanied by higher levels of circulating insulin. We also found the up-regulated expression of hypothalamic Ahi1 in high-fat induced obese mice, db/db mice, and streptozotocin induced diabetic mice. In addition, we demonstrated that insulin could decrease the expression of Ahi1 in neuroblastoma cell line N18TG2. Taken together, our results indicate that hypothalamic Ahi1 functions as a sensor of insulin signaling.
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Farooqui AA, Farooqui T, Panza F, Frisardi V. Metabolic syndrome as a risk factor for neurological disorders. Cell Mol Life Sci 2012; 69:741-62. [PMID: 21997383 PMCID: PMC11115054 DOI: 10.1007/s00018-011-0840-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 09/08/2011] [Accepted: 09/15/2011] [Indexed: 02/07/2023]
Abstract
The metabolic syndrome is a cluster of common pathologies: abdominal obesity linked to an excess of visceral fat, insulin resistance, dyslipidemia and hypertension. At the molecular level, metabolic syndrome is accompanied not only by dysregulation in the expression of adipokines (cytokines and chemokines), but also by alterations in levels of leptin, a peptide hormone released by white adipose tissue. These changes modulate immune response and inflammation that lead to alterations in the hypothalamic 'bodyweight/appetite/satiety set point,' resulting in the initiation and development of metabolic syndrome. Metabolic syndrome is a risk factor for neurological disorders such as stroke, depression and Alzheimer's disease. The molecular mechanism underlying the mirror relationship between metabolic syndrome and neurological disorders is not fully understood. However, it is becoming increasingly evident that all cellular and biochemical alterations observed in metabolic syndrome like impairment of endothelial cell function, abnormality in essential fatty acid metabolism and alterations in lipid mediators along with abnormal insulin/leptin signaling may represent a pathological bridge between metabolic syndrome and neurological disorders such as stroke, Alzheimer's disease and depression. The purpose of this review is not only to describe the involvement of brain in the pathogenesis of metabolic syndrome, but also to link the pathogenesis of metabolic syndrome with neurochemical changes in stroke, Alzheimer's disease and depression to a wider audience of neuroscientists with the hope that this discussion will initiate more studies on the relationship between metabolic syndrome and neurological disorders.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH 43221, USA.
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Maclean PS, Bergouignan A, Cornier MA, Jackman MR. Biology's response to dieting: the impetus for weight regain. Am J Physiol Regul Integr Comp Physiol 2011; 301:R581-600. [PMID: 21677272 PMCID: PMC3174765 DOI: 10.1152/ajpregu.00755.2010] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 06/08/2011] [Indexed: 01/02/2023]
Abstract
Dieting is the most common approach to losing weight for the majority of obese and overweight individuals. Restricting intake leads to weight loss in the short term, but, by itself, dieting has a relatively poor success rate for long-term weight reduction. Most obese people eventually regain the weight they have worked so hard to lose. Weight regain has emerged as one of the most significant obstacles for obesity therapeutics, undoubtedly perpetuating the epidemic of excess weight that now affects more than 60% of U.S. adults. In this review, we summarize the evidence of biology's role in the problem of weight regain. Biology's impact is first placed in context with other pressures known to affect body weight. Then, the biological adaptations to an energy-restricted, low-fat diet that are known to occur in the overweight and obese are reviewed, and an integrative picture of energy homeostasis after long-term weight reduction and during weight regain is presented. Finally, a novel model is proposed to explain the persistence of the "energy depletion" signal during the dynamic metabolic state of weight regain, when traditional adiposity signals no longer reflect stored energy in the periphery. The preponderance of evidence would suggest that the biological response to weight loss involves comprehensive, persistent, and redundant adaptations in energy homeostasis and that these adaptations underlie the high recidivism rate in obesity therapeutics. To be successful in the long term, our strategies for preventing weight regain may need to be just as comprehensive, persistent, and redundant, as the biological adaptations they are attempting to counter.
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Affiliation(s)
- Paul S Maclean
- University of Colorado Anschutz Medical Campus, Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, Center for Human Nutrition, Denver, Colorado, USA.
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Yuliana ND, Jahangir M, Korthout H, Choi YH, Kim HK, Verpoorte R. Comprehensive review on herbal medicine for energy intake suppression. Obes Rev 2011; 12:499-514. [PMID: 20659298 DOI: 10.1111/j.1467-789x.2010.00790.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The obesity drug development is present not a bright and successful story. So far, drugs reported to be effective, either from synthetic or natural sources, mostly stimulated controversy because of serious adverse effects, which ended with stopping clinical trials or even withdrawal from the market. However, obesity and its comorbidities have become rapidly a major problem in both developed and developing countries. This has encouraged pharmaceutical companies and academia to keep on struggling on developing novel effective but safe obesity drugs, and on characterizing novel obesity drug targets. From existing scientific work on obesity drug discovery and commercial slimming preparations, compounds originating from nature, especially from plants, seem to be the first choice. Traditional belief that herbal medicine is safer than synthetic ones is one of the classical arguments, although scientifically this is not always true (e.g. ban on Ephedra). But in general, it has been widely acknowledged that a plant compound, with its unique scaffolds and rich diversity is an unlimited source of novel lead compounds. This paper aims to summarize all works focused on screening plant materials by targeting important pathways related to energy intake regulation, either by in vivo or in vitro experiments.
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Affiliation(s)
- N D Yuliana
- Department of Pharmacognosy, Section of Metabolomics, Leiden University, Leiden, The Netherlands
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16
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Leloup C, Casteilla L, Carrière A, Galinier A, Benani A, Carneiro L, Pénicaud L. Balancing mitochondrial redox signaling: a key point in metabolic regulation. Antioxid Redox Signal 2011; 14:519-30. [PMID: 20977349 DOI: 10.1089/ars.2010.3424] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial reactive oxygen species (mROS) have emerged as signaling molecules in physiology primarily as a result of studies of uncoupling mechanisms in mitochondrial respiration. The discovery that this mechanism negatively regulates mROS generation in many cell types has drawn the attention of the scientific community to the pathological consequences of excess mROS production. From reports of the energetic fluxes in cells grown under normal conditions, the hypothesis that mROS are an integrated physiological signal of the metabolic status of the cell has emerged. Here, we consider recent studies that support this point of view in two key nutrient sensors of the body, beta cells and the hypothalamus, which are the main coordinators of endocrine and nervous controls of energy metabolism and adipose tissue, which is of paramount importance in controlling body weight and, therefore, the development of obesity and type 2 diabetes. In this context, finely balanced mROS production may be at the core of proper metabolic maintenance, and unbalanced mROS production, which is largely documented, might be an important trigger of metabolic disorders.
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Affiliation(s)
- Corinne Leloup
- Centre des Sciences du Goût et de l'Alimentation, Centre National de la Recherche Scientifique Unité Mixte de Recherche 6265-Institut National de Recherche Agronomique 1324, Université de Bourgogne, Dijon, France.
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17
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Polyák É, Gombos K, Hajnal B, Bonyár-Müller K, Szabó S, Gubicskó-Kisbenedek A, Marton K, Ember I. Effects of artificial sweeteners on body weight, food and drink intake. ACTA ACUST UNITED AC 2010; 97:401-7. [DOI: 10.1556/aphysiol.97.2010.4.9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Woods SC. The control of food intake: behavioral versus molecular perspectives. Cell Metab 2009; 9:489-98. [PMID: 19490904 PMCID: PMC3090647 DOI: 10.1016/j.cmet.2009.04.007] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 04/15/2009] [Accepted: 04/24/2009] [Indexed: 01/16/2023]
Abstract
To meet the continuous demand for energy, organisms use diverse signals to match food intake with energy needs. This paper reviews the effect of satiation signals and adiposity signals on food intake, including how they interact in the brain and how their influence changes with experience. Whereas meal initiation is influenced by external environmental factors, meal size is influenced by an array of signals that can be partitioned according to their reliability in indicating caloric content of food. It is argued that the malleability of satiation signals renders them poor candidates as pharmacological targets to control body weight.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry, University of Cincinnati, Cincinnati, OH 45237, USA.
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19
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Dzeja P, Terzic A. Adenylate kinase and AMP signaling networks: metabolic monitoring, signal communication and body energy sensing. Int J Mol Sci 2009; 10:1729-1772. [PMID: 19468337 PMCID: PMC2680645 DOI: 10.3390/ijms10041729] [Citation(s) in RCA: 297] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 03/26/2009] [Accepted: 04/02/2009] [Indexed: 12/20/2022] Open
Abstract
Adenylate kinase and downstream AMP signaling is an integrated metabolic monitoring system which reads the cellular energy state in order to tune and report signals to metabolic sensors. A network of adenylate kinase isoforms (AK1-AK7) are distributed throughout intracellular compartments, interstitial space and body fluids to regulate energetic and metabolic signaling circuits, securing efficient cell energy economy, signal communication and stress response. The dynamics of adenylate kinase-catalyzed phosphotransfer regulates multiple intracellular and extracellular energy-dependent and nucleotide signaling processes, including excitation-contraction coupling, hormone secretion, cell and ciliary motility, nuclear transport, energetics of cell cycle, DNA synthesis and repair, and developmental programming. Metabolomic analyses indicate that cellular, interstitial and blood AMP levels are potential metabolic signals associated with vital functions including body energy sensing, sleep, hibernation and food intake. Either low or excess AMP signaling has been linked to human disease such as diabetes, obesity and hypertrophic cardiomyopathy. Recent studies indicate that derangements in adenylate kinase-mediated energetic signaling due to mutations in AK1, AK2 or AK7 isoforms are associated with hemolytic anemia, reticular dysgenesis and ciliary dyskinesia. Moreover, hormonal, food and antidiabetic drug actions are frequently coupled to alterations of cellular AMP levels and associated signaling. Thus, by monitoring energy state and generating and distributing AMP metabolic signals adenylate kinase represents a unique hub within the cellular homeostatic network.
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Affiliation(s)
- Petras Dzeja
- Author to whom correspondence should be addressed; E-mail:
(P.D.)
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20
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Horvath TL, Andrews ZB, Diano S. Fuel utilization by hypothalamic neurons: roles for ROS. Trends Endocrinol Metab 2009; 20:78-87. [PMID: 19084428 DOI: 10.1016/j.tem.2008.10.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 10/07/2008] [Accepted: 10/07/2008] [Indexed: 02/06/2023]
Abstract
The hypothalamus plays a major part in regulating energy homeostasis by integrating hormonal and nutritional signals. Increasing evidence shows that specific neurons in the hypothalamus respond to changing glucose, lipid and amino acid levels. However, the intracellular substrate for such 'fuel sensing' and its integration into the neuronal doctrine as it relates to energy homeostasis remains elusive. Evidence points to differential fuel utilization in response to nutrient availability and free radical formation as crucial components in regulating neuronal functions. This review places these components in the context of neurobiological aspects of circuit-specific hypothalamic output, focusing on the melanocortin system. The effects of glucose and fatty acids are discussed with emphasis on free radical production in orexigenic and anorexigenic neurons of the arcuate nucleus.
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Affiliation(s)
- Tamas L Horvath
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
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21
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Woods SC, D'Alessio DA. Central control of body weight and appetite. J Clin Endocrinol Metab 2008; 93:S37-50. [PMID: 18987269 PMCID: PMC2585760 DOI: 10.1210/jc.2008-1630] [Citation(s) in RCA: 302] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 09/08/2008] [Indexed: 12/14/2022]
Abstract
CONTEXT Energy balance is critical for survival and health, and control of food intake is an integral part of this process. This report reviews hormonal signals that influence food intake and their clinical applications. EVIDENCE ACQUISITION A relatively novel insight is that satiation signals that control meal size and adiposity signals that signify the amount of body fat are distinct and interact in the hypothalamus and elsewhere to control energy homeostasis. This review focuses upon recent literature addressing the integration of satiation and adiposity signals and therapeutic implications for treatment of obesity. EVIDENCE SYNTHESIS During meals, signals such as cholecystokinin arise primarily from the GI tract to cause satiation and meal termination; signals secreted in proportion to body fat such as insulin and leptin interact with satiation signals and provide effective regulation by dictating meal size to amounts that are appropriate for body fatness, or stored energy. Although satiation and adiposity signals are myriad and redundant and reduce food intake, there are few known orexigenic signals; thus, initiation of meals is not subject to the degree of homeostatic regulation that cessation of eating is. There are now drugs available that act through receptors for satiation factors and which cause weight loss, demonstrating that this system is amenable to manipulation for therapeutic goals. CONCLUSIONS Although progress on effective medical therapies for obesity has been relatively slow in coming, advances in understanding the central regulation of food intake may ultimately be turned into useful treatment options.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry, University of Cincinnati, Cincinnati, OH 45237, USA.
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22
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Woods SC, Seeley RJ, Cota D. Regulation of food intake through hypothalamic signaling networks involving mTOR. Annu Rev Nutr 2008; 28:295-311. [PMID: 18429698 DOI: 10.1146/annurev.nutr.28.061807.155505] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To maintain normal activity, single cells must assure that their energy needs and utilization are continuously matched. Likewise, multicellular organisms must constantly coordinate energy intake and expenditure to maintain energy homeostasis. The brain, and the hypothalamus in particular, plays a critical role in integrating and coordinating several types of signals, including hormones and nutrients, to guarantee such homeostasis. Like single cells, the hypothalamus also profits from intracellular pathways known to work as fuel sensors to maintain energy balance. One such pathway is the mammalian target of rapamycin (mTOR). mTOR integrates different sensory inputs to regulate protein synthesis rates in individual cells, and it has recently been implicated in the central nervous system to regulate food intake and body weight as well. This review provides an overview of the role of hypothalamic intracellular fuel sensors in the overall control of energy balance and discusses the potential contribution of these fuel-sensing mechanisms to the metabolic dysregulation associated with obesity.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry, Genome Research Institute, University of Cincinnati, Cincinnati, Ohio 45237, USA.
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23
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Luhovyy BL, Akhavan T, Anderson GH. Whey proteins in the regulation of food intake and satiety. J Am Coll Nutr 2008; 26:704S-12S. [PMID: 18187437 DOI: 10.1080/07315724.2007.10719651] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Whey protein has potential as a functional food component to contribute to the regulation of body weight by providing satiety signals that affect both short-term and long-term food intake regulation. Because whey is an inexpensive source of high nutritional quality protein, the utilization of whey as a physiologically functional food ingredient for weight management is of current interest. At present, the role of individual whey proteins and peptides in contributing to food intake regulation has not been fully defined. However, Whey protein reduces short-term food intake relative to placebo, carbohydrate and other proteins. Whey protein affects satiation and satiety by the actions of: (1) whey protein fractions per se; (2) bioactive peptides; (3) amino-acids released after digestion; (4) combined action of whey protein and/or peptides and/or amino acids with other milk constituents. Whey ingestion activates many components of the food intake regulatory system. Whey protein is insulinotropic, and whey-born peptides affect the renin-angiotensin system. Therefore whey protein has potential as physiologically functional food component for persons with obesity and its co-morbidities (hypertension, type II diabetes, hyper- and dislipidemia). It remains unclear, however, if the favourable effects of whey on food intake, subjective satiety and intake regulatory mechanisms in humans are obtained from usual serving sizes of dairy products. The effects described have been observed in short-term experiments and when whey is consumed in much higher amounts.
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Affiliation(s)
- Bohdan L Luhovyy
- Department of Nutritional Sciences, University of Toronto, Rm 329, FitzGerald Building, 150 College St, Toronto, Ontario, Canada.
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24
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Abstract
Neuronal control of body energy homeostasis is the key mechanism by which animals and humans regulate their long-term energy balance. Various hypothalamic neuronal circuits (which include the hypothalamic melanocortin, midbrain dopamine reward and caudal brainstem autonomic feeding systems) control energy intake and expenditure to maintain body weight within a narrow range for long periods of a life span. Numerous peripheral metabolic hormones and nutrients target these structures providing feedback signals that modify the default "settings" of neuronal activity to accomplish this balance. A number of molecular genetic tools for manipulating individual components of brain energy homeostatic machineries, in combination with anatomical, electrophysiological, pharmacological and behavioral techniques, have been developed, which provide a means for elucidating the complex molecular and cellular mechanisms of feeding behavior and metabolism. This review will highlight some of these advancements and focus on the neuronal circuitries of energy homeostasis.
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Affiliation(s)
- Qian Gao
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, United States.
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25
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Abstract
Significant advancements have been made in the past century regarding the neuronal control of feeding behavior and energy expenditure. The effects and mechanisms of action of various peripheral metabolic signals on the brain have become clearer. Molecular and genetic tools for visualizing and manipulating individual components of brain homeostatic systems in combination with neuroanatomical, electrophysiological, behavioral, and pharmacological techniques have begun to elucidate the molecular and neuronal mechanisms of complex feeding behavior and energy expenditure. This review highlights some of these advancements that have led to the current understanding of the brain's involvement in the acute and chronic regulation of energy homeostasis.
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Affiliation(s)
- Qian Gao
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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Morrison CD, Xi X, White CL, Ye J, Martin RJ. Amino acids inhibit Agrp gene expression via an mTOR-dependent mechanism. Am J Physiol Endocrinol Metab 2007; 293:E165-71. [PMID: 17374702 PMCID: PMC2596875 DOI: 10.1152/ajpendo.00675.2006] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Metabolic fuels act on hypothalamic neurons to regulate feeding behavior and energy homeostasis, but the signaling mechanisms mediating these effects are not fully clear. Rats placed on a low-protein diet (10% of calories) exhibited increased food intake (P < 0.05) and hypothalamic Agouti-related protein (Agrp) gene expression (P = 0.002). Direct intracerebroventricular injection of either an amino acid mixture (RPMI 1640) or leucine alone (1 mug) suppressed 24-h food intake (P < 0.05), indicating that increasing amino acid concentrations within the brain is sufficient to suppress food intake. To define a cellular mechanism for these direct effects, GT1-7 hypothalamic cells were exposed to low amino acids for 16 h. Decreasing amino acid availability increased Agrp mRNA levels in GT1-7 cells (P < 0.01), and this effect was attenuated by replacement of the amino acid leucine (P < 0.05). Acute exposure to elevated amino acid concentrations increased ribosomal protein S6 kinase phosphorylation via a rapamycin-sensitive mechanism, suggesting that amino acids directly stimulated mammalian target of rapamycin (mTOR) signaling. To test whether mTOR signaling contributes to amino acid inhibition of Agrp gene expression, GT1-7 cells cultured in either low or high amino acids for 16 h and were also treated with rapamcyin (50 nM). Rapamycin treatment increased Agrp mRNA levels in cells exposed to high amino acids (P = 0.01). Taken together, these observations indicate that amino acids can act within the brain to inhibit food intake and that a direct, mTOR-dependent inhibition of Agrp gene expression may contribute to this effect.
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Affiliation(s)
- Christopher D Morrison
- Neurobehavior Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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27
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28
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de Fátima Haueisen Sander Diniz M, de Azeredo Passos VM, Diniz MTC. Gut-brain communication: how does it stand after bariatric surgery? Curr Opin Clin Nutr Metab Care 2006; 9:629-36. [PMID: 16912562 DOI: 10.1097/01.mco.0000241676.63041.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW This article aims to critically review the literature, describing the possible implications of different bariatric surgery techniques in gastrointestinal peptides and their relation with the neural paths involved in the central regulation of appetite and satiety: the gut-brain axis. RECENT FINDINGS Bariatric surgery operations change orexigenic and anorexigenic gastrointestinal peptide levels. Forty-one studies were analyzed in order to understand the effects of different operations on the behavior of gut peptides (ghrelin, cholecystokinin, peptide YY, glucagon-like peptide-1, gastric inhibitory polypeptide, pancreatic polypeptide). The authors have tried to correlate these findings with weight loss/maintenance via different surgical techniques. SUMMARY The present line of research is recent and there is a lack of comparability between studies. There are different design approaches and study protocols, different laboratorial exams. Prospective long-term studies with larger samples are needed to clarify the effects of bariatric operations on the gut-brain axis.
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29
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Abstract
PURPOSE OF REVIEW This review summarizes the experimental data demonstrating the fundamental role of kisspeptins and their G protein-coupled receptor GPR54 in the control of reproduction, with special emphasis on their function at puberty. RECENT FINDINGS Kisspeptins, products of the KiSS-1 gene, were originally identified as metastasis suppressor peptides with the ability to bind G protein-coupled receptor GPR54. In late 2003, loss-of-function mutations of the GPR54 gene were found in patients suffering from hypogonadotropic hypogonadism. This finding kicked off the analysis of the role of the KiSS-1/GPR54 system in the control of reproduction. Kisspeptins are very potent elicitors of gonadotropin secretion, primarily through stimulation of gonadotropin-releasing hormone release. Enhanced expression of KiSS-1 and GPR54 genes, as well as increased GPR54 signaling, are detected at the hypothalamus during pubertal development, and activation of GPR54 by administration of kisspeptin is sufficient to induce precocious activation of the gonadotropic axis in immature rodents and monkeys. Hypothalamic KiSS-1 also functions as an essential integrator for peripheral inputs, including gonadal steroids and nutritional signals, controlling gonadotropin-releasing hormone and gonadotropin secretion. SUMMARY Kisspeptins and their putative receptor, GPR54, have recently emerged as indispensable factors for pubertal development, with a key role as gatekeepers of gonadotropin-releasing hormone release neurons and, hence, of reproductive function.
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Affiliation(s)
- Manuel Tena-Sempere
- Physiology Section, Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.
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Woods SC, Lutz TA, Geary N, Langhans W. Pancreatic signals controlling food intake; insulin, glucagon and amylin. Philos Trans R Soc Lond B Biol Sci 2006; 361:1219-35. [PMID: 16815800 PMCID: PMC1642707 DOI: 10.1098/rstb.2006.1858] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The control of food intake and body weight by the brain relies upon the detection and integration of signals reflecting energy stores and fluxes, and their interaction with many different inputs related to food palatability and gastrointestinal handling as well as social, emotional, circadian, habitual and other situational factors. This review focuses upon the role of hormones secreted by the endocrine pancreas: hormones, which individually and collectively influence food intake, with an emphasis upon insulin, glucagon and amylin. Insulin and amylin are co-secreted by B-cells and provide a signal that reflects both circulating energy in the form of glucose and stored energy in the form of visceral adipose tissue. Insulin acts directly at the liver to suppress the synthesis and secretion of glucose, and some plasma insulin is transported into the brain and especially the mediobasal hypothalamus where it elicits a net catabolic response, particularly reduced food intake and loss of body weight. Amylin reduces meal size by stimulating neurons in the hindbrain, and there is evidence that amylin additionally functions as an adiposity signal controlling body weight as well as meal size. Glucagon is secreted from A-cells and increases glucose secretion from the liver. Glucagon acts in the liver to reduce meal size, the signal being relayed to the brain via the vagus nerves. To summarize, hormones of the endocrine pancreas are collectively at the crossroads of many aspects of energy homeostasis. Glucagon and amylin act in the short term to reduce meal size, and insulin sensitizes the brain to short-term meal-generated satiety signals; and insulin and perhaps amylin as well act over longer intervals to modulate the amount of fat maintained and defended by the brain. Hormones of the endocrine pancreas interact with receptors at many points along the gut-brain axis, from the liver to the sensory vagus nerve to the hindbrain to the hypothalamus; and their signals are conveyed both neurally and humorally. Finally, their actions include gastrointestinal and metabolic as well as behavioural effects.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry, University of Cincinnati, OH 45237 USA.
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31
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Affiliation(s)
- Diego Perez-Tilve
- University of Cincinnati, Genome Research Institute, Department of Psychiatry, Obesity Research Center, 2170 East Galbraith Road, Cincinnati, Ohio 45327, USA
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Pagotto U, Marsicano G, Cota D, Lutz B, Pasquali R. The emerging role of the endocannabinoid system in endocrine regulation and energy balance. Endocr Rev 2006; 27:73-100. [PMID: 16306385 DOI: 10.1210/er.2005-0009] [Citation(s) in RCA: 578] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
During the last few years, the endocannabinoid system has emerged as a highly relevant topic in the scientific community. Many different regulatory actions have been attributed to endocannabinoids, and their involvement in several pathophysiological conditions is under intense scrutiny. Cannabinoid receptors, named CB1 receptor and CB2 receptor, first discovered as the molecular targets of the psychotropic component of the plant Cannabis sativa, participate in the physiological modulation of many central and peripheral functions. CB2 receptor is mainly expressed in immune cells, whereas CB1 receptor is the most abundant G protein-coupled receptor expressed in the brain. CB1 receptor is expressed in the hypothalamus and the pituitary gland, and its activation is known to modulate all the endocrine hypothalamic-peripheral endocrine axes. An increasing amount of data highlights the role of the system in the stress response by influencing the hypothalamic-pituitary-adrenal axis and in the control of reproduction by modifying gonadotropin release, fertility, and sexual behavior. The ability of the endocannabinoid system to control appetite, food intake, and energy balance has recently received great attention, particularly in the light of the different modes of action underlying these functions. The endocannabinoid system modulates rewarding properties of food by acting at specific mesolimbic areas in the brain. In the hypothalamus, CB1 receptor and endocannabinoids are integrated components of the networks controlling appetite and food intake. Interestingly, the endocannabinoid system was recently shown to control metabolic functions by acting on peripheral tissues, such as adipocytes, hepatocytes, the gastrointestinal tract, and, possibly, skeletal muscle. The relevance of the system is further strenghtened by the notion that drugs interfering with the activity of the endocannabinoid system are considered as promising candidates for the treatment of various diseases, including obesity.
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Affiliation(s)
- Uberto Pagotto
- Endocrinology Unit, Department of Internal Medicine and Gastroenterology, Sant' Orsola-Malpighi Hospital, Bologna, Italy, and Department of Physiological Chemistry, Johannes Gutenberg-University Mainz, Germany.
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