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Perry RA, Craig SL, Gault VA, Flatt PR, Irwin N. A novel neurotensin/xenin fusion peptide enhances β-cell function and exhibits antidiabetic efficacy in high-fat fed mice. Biosci Rep 2021; 41:BSR20211275. [PMID: 34370015 PMCID: PMC8390788 DOI: 10.1042/bsr20211275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/28/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022] Open
Abstract
Neurotensin and xenin possess antidiabetic potential, mediated in part through augmentation of incretin hormone, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), action. In the present study, fragment peptides of neurotensin and xenin, acetyl-neurotensin and xenin-8-Gln, were fused together to create Ac-NT/XN-8-Gln. Following assessment of enzymatic stability, effects of Ac-NT/XN-8-Gln on in vitro β-cell function were studied. Subchronic antidiabetic efficacy of Ac-NT/XN-8-Gln alone, and in combination with the clinically approved GLP-1 receptor agonist exendin-4, was assessed in high-fat fed (HFF) mice. Ac-NT/XN-8-Gln was highly resistant to plasma enzyme degradation and induced dose-dependent insulin-releasing actions (P<0.05 to P<0.01) in BRIN-BD11 β-cells and isolated mouse islets. Ac-NT/XN-8-Gln augmented (P<0.001) the insulinotropic actions of GIP, while possessing independent β-cell proliferative (P<0.001) and anti-apoptotic (P<0.01) actions. Twice daily treatment of HFF mice with Ac-NT/XN-8-Gln for 32 days improved glycaemic control and circulating insulin, with benefits significantly enhanced by combined exendin-4 treatment. This was reflected by reduced body fat mass (P<0.001), improved circulating lipid profile (P<0.01) and reduced HbA1c concentrations (P<0.01) in the combined treatment group. Following an oral glucose challenge, glucose levels were markedly decreased (P<0.05) only in combination treatment group and superior to exendin-4 alone, with similar observations made in response to glucose plus GIP injection. The combined treatment group also presented with improved insulin sensitivity, decreased pancreatic insulin content as well as increased islet and β-cell areas. These data reveal that Ac-NT/XN-8-Gln is a biologically active neurotensin/xenin fusion peptide that displays prominent antidiabetic efficacy when administered together with exendin-4.
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Affiliation(s)
- Rachele A. Perry
- Ulster University, School of Pharmacy and Pharmaceutical Sciences, Diabetes Research Group, Coleraine, Northern Ireland, U.K
| | - Sarah. L. Craig
- Ulster University, School of Pharmacy and Pharmaceutical Sciences, Diabetes Research Group, Coleraine, Northern Ireland, U.K
| | - Victor A. Gault
- Ulster University, School of Pharmacy and Pharmaceutical Sciences, Diabetes Research Group, Coleraine, Northern Ireland, U.K
| | - Peter R. Flatt
- Ulster University, School of Pharmacy and Pharmaceutical Sciences, Diabetes Research Group, Coleraine, Northern Ireland, U.K
| | - Nigel Irwin
- Ulster University, School of Pharmacy and Pharmaceutical Sciences, Diabetes Research Group, Coleraine, Northern Ireland, U.K
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Tomotaki S, Araki R, Motokura K, Tomobe Y, Yamauchi T, Hanaoka S, Tomotaki H, Iwanaga K, Niwa F, Takita J, Kawai M. Effects of passage through the digestive tract on incretin secretion: Before and after birth. J Diabetes Investig 2021; 12:970-977. [PMID: 33095973 PMCID: PMC8169361 DOI: 10.1111/jdi.13447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 11/29/2022] Open
Abstract
AIMS/INTRODUCTION It was reported that fetuses secrete endogenous incretin; however, the stimulants of fetal incretin secretion are not fully understood. To investigate the association between the passage of amniotic fluid through the intestinal tract and fetal secretion of incretin, we analyzed umbilical cord incretin levels of infants with duodenum atresia. MATERIALS AND METHODS Infants born from July 2017 to July 2019 (infants with duodenum atresia and normal term or preterm infants) were enrolled. We measured and compared the concentrations of glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide/glucose-dependent insulinotropic polypeptide (GIP) in the umbilical vein and preprandial blood samples after birth. RESULTS A total of 98 infants (47 term, 46 preterm and 5 with duodenum atresia) were included. In patients with duodenum atresia, umbilical vein GLP-1 and GIP levels were the same as those in normal infants. In postnatal samples, there were positive correlations between the amount of enteral feeding and preprandial serum concentrations of GLP-1 (r = 0.47) or GIP (r = 0.49). CONCLUSIONS Our results show that enteral feeding is important for secretion of GLP-1 and GIP in postnatal infants, whereas the passage of amniotic fluid is not important for fetal secretion of GLP-1 and GIP. The effect of ingested material passing through the digestive tract on incretin secretion might change before and after birth. Other factors might stimulate secretion of GLP-1 and GIP during the fetal period.
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Affiliation(s)
- Seiichi Tomotaki
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Ryosuke Araki
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Kouji Motokura
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Yutaro Tomobe
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Takeru Yamauchi
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Shintaro Hanaoka
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Hiroko Tomotaki
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Kougoro Iwanaga
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Fusako Niwa
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Junko Takita
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
| | - Masahiko Kawai
- Department of PediatricsGraduate School of MedicineKyoto UniversityKyotoJapan
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Higgins PB, Shade RE, Rodríguez-Sánchez IP, Garcia-Forey M, Tejero ME, Voruganti VS, Cole SA, Comuzzie AG, Folli F. Central GIP signaling stimulates peripheral GIP release and promotes insulin and pancreatic polypeptide secretion in nonhuman primates. Am J Physiol Endocrinol Metab 2016; 311:E661-E670. [PMID: 27530231 PMCID: PMC5241561 DOI: 10.1152/ajpendo.00166.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/10/2016] [Indexed: 01/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) has important actions on whole body metabolic function. GIP and its receptor are also present in the central nervous system and have been linked to neurotrophic actions. Metabolic effects of central nervous system GIP signaling have not been reported. We investigated whether centrally administered GIP could increase peripheral plasma GIP concentrations and influence the metabolic response to a mixed macronutrient meal in nonhuman primates. An infusion and sampling system was developed to enable continuous intracerebroventricular (ICV) infusions with serial venous sampling in conscious nonhuman primates. Male baboons (Papio sp.) that were healthy and had normal body weights (28.9 ± 2.1 kg) were studied (n = 3). Animals were randomized to receive continuous ICV infusions of GIP (20 pmol·kg-1·h-1) or vehicle before and over the course of a 300-min mixed meal test (15 kcal/kg, 1.5g glucose/kg) on two occasions. A significant increase in plasma GIP concentration was observed under ICV GIP infusion (66.5 ± 8.0 vs. 680.6 ± 412.8 pg/ml, P = 0.04) before administration of the mixed meal. Increases in postprandial, but not fasted, insulin (P = 0.01) and pancreatic polypeptide (P = 0.04) were also observed under ICV GIP. Effects of ICV GIP on fasted or postprandial glucagon, glucose, triglyceride, and free fatty acids were not observed. Our data demonstrate that central GIP signaling can promote increased plasma GIP concentrations independent of nutrient stimulation and increase insulin and pancreatic polypeptide responses to a mixed meal.
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Affiliation(s)
- Paul B Higgins
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas; Southwest National Primate Research Center, San Antonio, Texas;
| | - Robert E Shade
- Southwest National Primate Research Center, San Antonio, Texas
| | - Irám P Rodríguez-Sánchez
- Department of Genetics, School of Medicine, Autonomous University of Nuevo León (Universidad Autonoma de Nuevo León), Monterrey, Nuevo León, Mexico
| | | | - M Elizabeth Tejero
- Laboratory of Nutrigenetics and Nutrigenomics, National Institute of Genomic Medicine (Instituto Nacional de Medicina Genómica), Mexico City, Mexico
| | - V Saroja Voruganti
- Department of Nutrition and UNC Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina
| | - Shelley A Cole
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas
| | - Anthony G Comuzzie
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas; Southwest National Primate Research Center, San Antonio, Texas
| | - Franco Folli
- Southwest National Primate Research Center, San Antonio, Texas; Diabetes Division, Department of Medicine, University of Texas Health Sciences Center at San Antonio, San Antonio, Texas; Department of Medicine, Obesity and Comorbidities Research Center, University of Campinas, Campinas, São Paulo, Brazil; and Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
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Yavropoulou MP, Kotsa K, Pikilidou M, Keisisoglou I, Yovos JG. Effects of intracerebroventricular infusion of somatostatin-14 on peripheral glucoregulation in dogs. J Neuroendocrinol 2014; 26:11-7. [PMID: 24325321 DOI: 10.1111/jne.12124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/31/2013] [Accepted: 12/06/2013] [Indexed: 11/30/2022]
Abstract
Somatostatin (SST) is an inhibitory hormone that regulates numerous biological processes and circulates in two bioactive isoforms: SST-14 and SST-28. SST-14 is the predominant form in the hypothalamus and regulates the secretion of growth hormone (GH) (directly) and of thyroid-stimulating hormone (indirectly). In the periphery, SST is a potent inhibitor of glucagon and insulin secretion. In the present study, we aimed to investigate the effect of i.c.v. administration of SST-14 on glucose metabolism. Twenty healthy adult dogs randomly received either a bolus i.c.v. infusion of 5, 25 or 50 μg of SST-14 or an equivalent amount of artificial cerebrospinal fluid through an epicranial apparatus during fasting. The same experiment was repeated during concomitant intraduodenal infusion of glucose solution through a Mann-Bollman fistula. Serum levels of glucose, insulin and glucose-dependent insulinotrophic peptide (GIP), plasma SST and serum GH levels were assayed. Circulating levels of SST and GH did not change significantly during i.c.v. infusions. Bolus infusion of 50 μg of SST-14 produced an increase in serum glucose levels at 10 min (94 ± 2.5 mg/dl at baseline versus 101 ± 3 mg/dl, P = 0.04) and significantly suppressed insulin levels, reaching maximal suppression at 60 min after infusion (9 ± 1.3 μIU/ml at baseline versus 4.6 ± 0.5 μIU/ml P = 0.04) in fasting animals. Similar results were obtained during intraduodenal infusion of glucose through a Mann-Bollman fistula. GIP levels did not change significantly during i.c.v. administration of SST-14. Intracerebroventricular infusion of SST-14 increases glucose and suppresses insulin levels in the periphery independently of circulating SST levels.
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Affiliation(s)
- M P Yavropoulou
- Department of Endocrinology and Metabolism, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Paschetta E, Hvalryg M, Musso G. Glucose-dependent insulinotropic polypeptide: from pathophysiology to therapeutic opportunities in obesity-associated disorders. Obes Rev 2011; 12:813-28. [PMID: 21815989 DOI: 10.1111/j.1467-789x.2011.00897.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a hormone secreted from the intestinal K-cells with established insulin-releasing actions. However, the GIP receptor is widely distributed in peripheral organs, including the adipose tissue, gut, bone and brain, where GIP modulates energy intake, cell metabolism and proliferation, and lipid and glucose metabolism, eventually promoting lipid and glucose storage. In diabetes and obesity, the incretin effect of GIP is blunted, while the extrapancreatic tissues keep a normal sensitivity to this hormone. As GIP levels are normal or elevated in obesity and diabetes, mounting evidence from chemical or genetic GIP deletion in animal models of obesity-related diabetes suggests that GIP may have a pro-obesogenic action and that a strategy antagonizing GIP action may be beneficial in these conditions, clearing triglyceride deposits from adipose tissue, liver and muscle, and restoring normal insulin sensitivity. Emerging evidence also suggests that the metabolic benefits of bypass surgery are mediated, at least in part, by surgical removal of GIP-secreting K-cells in the upper small intestine.
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Affiliation(s)
- E Paschetta
- Department of Internal Medicine, University of Turin, Turin, Italy Helgelandssykehu set, Mosjøen, Norway Gradenigo Hospital, Turin, Italy
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Mustain WC, Rychahou PG, Evers BM. The role of neurotensin in physiologic and pathologic processes. Curr Opin Endocrinol Diabetes Obes 2011; 18:75-82. [PMID: 21124211 DOI: 10.1097/med.0b013e3283419052] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE OF REVIEW Neurotensin is a 13-amino acid peptide found in the central nervous system central nervous system and the gastrointestinal tract. Since its initial discovery in 1973, neurotensin has been shown to play a role in a wide range of physiologic and pathologic processes throughout the body. Ongoing research efforts continue to clarify the role of neurotensin in various central nervous system and gastrointestinal processes, as well as how disruption of these normal mechanisms may lead to diseases ranging from schizophrenia to colorectal cancer. The goal of this review is to provide an overview of the most recent advances in the field of neurotensin research, in the context of what has been previously published. RECENT FINDINGS Because of the seemingly unrelated functions of neurotensin in the central nervous system and the periphery, the scope of the articles reviewed is rather broad. Contributions continue to be made to our understanding of the downstream effects of neurotensin signaling and the complex feedback loops between neurotensin and other signaling molecules. By selective targeting or blockade of specific neurotensin receptors, investigators have identified potential drugs for use in the treatment of schizophrenia, alcoholism, chronic pain, or cancer. Neurotensin-based pharmacologic agents are being used successfully in animal models for a number of these conditions. SUMMARY The review highlights the wide array of biological processes in which neurotensin has a role, and summarizes the most recent advances in various fields of neurotensin research. The knowledge gained through this research has led to the development of first-in-class drugs for the treatment of various medical conditions, and it is clear that in the coming years some of these agents will be ready to move from the bench to the bedside in clinical trials.
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Affiliation(s)
- W Conan Mustain
- Department of Surgery, University of Kentucky, Lexington, Kentucky, USA
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Yavropoulou MP, Yovos JG. Central Regulation of Glucose-Dependent Insulinotropic Polypeptide Secretion. VITAMINS AND HORMONES 2010; 84:185-201. [DOI: 10.1016/b978-0-12-381517-0.00006-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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