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Fitzgerald PCE, Manoliu B, Herbillon B, Steinert RE, Horowitz M, Feinle-Bisset C. Effects of L-Phenylalanine on Energy Intake and Glycaemia-Impacts on Appetite Perceptions, Gastrointestinal Hormones and Gastric Emptying in Healthy Males. Nutrients 2020; 12:nu12061788. [PMID: 32560181 PMCID: PMC7353198 DOI: 10.3390/nu12061788] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 02/07/2023] Open
Abstract
In humans, phenylalanine stimulates plasma cholecystokinin (CCK) and pyloric pressures, both of which are important in the regulation of energy intake and gastric emptying. Gastric emptying is a key determinant of postprandial blood glucose. We evaluated the effects of intragastric phenylalanine on appetite perceptions and subsequent energy intake, and the glycaemic response to, and gastric emptying of, a mixed-nutrient drink. The study consisted of two parts, each including 16 healthy, lean males (age: 23 ± 1 years). In each part, participants received on three separate occasions, in randomised, double-blind fashion, 5 g (Phe-5 g) or 10g ('Phe-10 g) L-phenylalanine, or control, intragastrically, 30 min before a standardised buffet-meal (part A), or a standardised mixed-nutrient drink (part B). In part A, plasma CCK and peptide-YY (PYY), and appetite perceptions, were measured at baseline, after phenylalanine alone, and following the buffet-meal, from which energy intake was assessed. In part B, plasma glucose, glucagon-like peptide-1 (GLP-1), insulin and glucagon were measured at baseline, after phenylalanine alone, and for 2 h following the drink. Gastric emptying of the drink was also measured by 13C-acetate breath-test. Phe-10 g, but not Phe-5 g, stimulated plasma CCK (p = 0.01) and suppressed energy intake (p = 0.012); energy intake was correlated with stimulation of CCK (r = -0.4, p = 0.027), and tended to be associated with stimulation of PYY (r = -0.31, p = 0.082). Both Phe-10 g and Phe-5 g stimulated insulin and glucagon (all p < 0.05), but not GLP-1. Phe-10 g, but not Phe-5 g, reduced overall plasma glucose (p = 0.043) and peak plasma glucose (p = 0.017) in response to the mixed-nutrient drink. Phenylalanine had no effect on gastric emptying of the drink. In conclusion, our observations indicate that the energy intake-suppressant effect of phenylalanine is related to the stimulation of CCK and PYY, while the glucoregulatory effect may be independent of stimulation of plasma GLP-1 or slowing of gastric emptying.
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Affiliation(s)
- Penelope C. E. Fitzgerald
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Benoit Manoliu
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Benjamin Herbillon
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Robert E. Steinert
- Department of Surgery, Division of Visceral and Transplantation Surgery, University Hospital Zürich, 8091 Zürich, Switzerland;
| | - Michael Horowitz
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
| | - Christine Feinle-Bisset
- Adelaide Medical School and Centre of Research Excellence in Translating Nutritional Science to Good Health, Level 5 Adelaide Health and Medical Sciences Building, Corner North Terrace and George Street, Adelaide 5005, Australia; (P.C.E.F.); (B.M.); (B.H.); (M.H.)
- Correspondence: ; Tel.: +61-8-8313-6053
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Tapadia M, Carlessi R, Johnson S, Utikar R, Newsholme P. Lupin seed hydrolysate promotes G-protein-coupled receptor, intracellular Ca 2+ and enhanced glycolytic metabolism-mediated insulin secretion from BRIN-BD11 pancreatic beta cells. Mol Cell Endocrinol 2019; 480:83-96. [PMID: 30347229 DOI: 10.1016/j.mce.2018.10.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/14/2022]
Abstract
Lupin seed proteins have been reported to exhibit hypoglycaemic effects in animals and humans following oral administration, however little is known about its mechanism of action. This study investigated the signalling pathway(s) responsible for the insulinotropic effect of the hydrolysate obtained from lupin (Lupinus angustifolius L.) seed extracts utilizing BRIN-BD11 β-cells. The extract was treated with digestive enzymes to give a hydrolysate rich in biomolecules ≤7 kDa. Cells exhibited hydrolysate induced dose-dependent stimulation of insulin secretion and enhanced intracellular Ca2+ and glucose metabolism. The stimulatory effect of the hydrolysate was potentiated by depolarizing concentrations of KCl and was blocked by inhibitors of the ATP sensitive K+ channel, Gαq protein, phospholipase C (PLC) and protein kinase C (PKC). These findings reveal a novel mechanism for lupin hydrolysate stimulated insulin secretion via Gαq mediated signal transduction (Gαq/PLC/PKC) in the β-cells. Thus, lupin hydrolysates may have potential for nutraceutical treatment in type 2 diabetes.
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Affiliation(s)
- Mrunmai Tapadia
- Western Australia School of Mines (WASM): Minerals, Energy and Chemical Engineering, Curtin University, Perth, WA, 6102, Australia
| | - Rodrigo Carlessi
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute Biosciences, Curtin University, Perth, WA, 6102, Australia.
| | - Stuart Johnson
- School of Molecular and Life Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6845, Australia
| | - Ranjeet Utikar
- Western Australia School of Mines (WASM): Minerals, Energy and Chemical Engineering, Curtin University, Perth, WA, 6102, Australia
| | - Philip Newsholme
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute Biosciences, Curtin University, Perth, WA, 6102, Australia.
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3
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Lin X, Zhao L, Tang S, Zhou Q, Lin Q, Li X, Zheng H, Gao H. Metabolic effects of basic fibroblast growth factor in streptozotocin-induced diabetic rats: A 1H NMR-based metabolomics investigation. Sci Rep 2016; 6:36474. [PMID: 27808173 PMCID: PMC5093531 DOI: 10.1038/srep36474] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/14/2016] [Indexed: 12/11/2022] Open
Abstract
The fibroblast growth factors (FGFs) family shows a great potential in the treatment of diabetes, but little attention is paid to basic FGF (bFGF). In this study, to explore the metabolic effects of bFGF on diabetes, metabolic changes in serum and feces were analyzed in the normal rats, the streptozocin (STZ)-induced diabetic rats and the bFGF-treated diabetic rats using a 1H nuclear magnetic resonance (NMR)-based metabolomic approach. Interestingly, bFGF treatment significantly decreased glucose, lipid and low density lipoprotein/very low density lipoprotein (LDL/VLDL) levels in serum of diabetic rats. Moreover, bFGF treatment corrected diabetes-induced reductions in citrate, lactate, choline, glycine, creatine, histidine, phenylalanine, tyrosine and glutamine in serum. Fecal propionate was significantly increased after bFGF treatment. Correlation analysis shows that glucose, lipid and LDL/VLDL were significantly negatively correlated with energy metabolites (citrate, creatine and lactate) and amino acids (alanine, glycine, histidine, phenylalanine, tyrosine and glutamine). In addition, a weak but significant correlation was observed between fecal propionate and serum lipid (R = −0.35, P = 0.046). Based on metabolic correlation and pathway analysis, therefore, we suggest that the glucose and lipid lowering effects of bFGF in the STZ-induced diabetic rats may be achieved by activating microbial metabolism, increasing energy metabolism and correcting amino acid metabolism.
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Affiliation(s)
- Xiaodong Lin
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Liangcai Zhao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.,Metabonomics Section of Collaborative Innovation Center of Biomedicine, Wenzhou Medical University-Wenzhou University, Wenzhou 325035, China
| | - Shengli Tang
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Qi Zhou
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Qiuting Lin
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiaokun Li
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.,Metabonomics Section of Collaborative Innovation Center of Biomedicine, Wenzhou Medical University-Wenzhou University, Wenzhou 325035, China
| | - Hong Zheng
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.,Metabonomics Section of Collaborative Innovation Center of Biomedicine, Wenzhou Medical University-Wenzhou University, Wenzhou 325035, China
| | - Hongchang Gao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.,Metabonomics Section of Collaborative Innovation Center of Biomedicine, Wenzhou Medical University-Wenzhou University, Wenzhou 325035, China
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4
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Lorenzo MP, Dudzik D, Varas E, Gibellini M, Skotnicki M, Zorawski M, Zarzycki W, Pellati F, García A. Optimization and validation of a chiral GC-MS method for the determination of free D-amino acids ratio in human urine: application to a gestational diabetes mellitus study. J Pharm Biomed Anal 2015; 107:480-7. [PMID: 25679092 DOI: 10.1016/j.jpba.2015.01.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 12/31/2022]
Abstract
Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance with onset or first recognition during pregnancy. It is affecting approximately up to 14% of all pregnancies with an increasing tendency. GDM has been related to relevant short-term and long-term health complications for both mother and offspring. Recent studies strongly emphasized the role of several essential amino acids in the pathogenesis of obesity and highlighted their strong correlation with insulin resistance, but there are no references related to modifications in D-AAs in biological fluids. As D-AA elimination proceeds mainly by renal excretion, urine was the selected sample to evaluate the alterations in free D-AAs ratio in a GDM study. Only 1 mL of first void urine or standard solution was required for purification, by using a Discovery DSC-SCX SPE cartridge (500 mg/3 mL) and derivatization into their N(O)-pentafluoropropionyl amino acid 2-propyl esters. Enantiomeric separation was carried out by GC-MS on a Chirasil-L-Val N-propionyl-L-valine-tert-butylamide polysiloxane fused-silica capillary column (25 m×0.25 mm I.D., 0.12 μm film thickness, Agilent Technologies, Waldbronn, Germany), under programmed temperature elution. Detection was performed with an ion trap mass analyzer, operating in the full scan mode in the m/z 50-350 range. 14 pairs of derivatives of D-and L-AAs were separated. The steps of sample preparation, derivatization and GC-MS conditions were optimized for both urine and standards. Several conditions affecting the SPE procedure, such as sorbent mass/volume ratio of the cartridge, sample dilution and pH, were optimized. Volume of reagents and solvents and reaction temperature and time were also tested for the derivatization. Regarding the GC-MS parameters, split ratio, temperature program and mass range were optimized. The final method was validated in terms of linearity, sensitivity, accuracy and precision for D-Ala, D-Pro, D-Ser, D-Met, D-Phe, D-Glu, D-Orn and D-Lys. Identification of AAs in urine samples was based on retention time and mass spectra. Urine from 20 women with GDM and 20 pregnant women with normal glucose tolerance (after 2-h 75-g oral glucose tolerance test), matched according to the week of gestation and age (22-28 week of gestation and age 24-37 years), were enrolled into the study. %D-Relative amounts were determined for Ala, Val, Thr, Ser, Leu, Asx (Asp+Asn), Glx (Glu+Gln), Met, Phe, Tyr, Orn and Lys. Statistically significant differences (p<0.05) were observed only for D-Phe and higher values were found in the GDM group. It is possible that D-Phe could be involved in metabolic/signaling pathways to compensate early stages of insulin resistance, although further work is necessary to confirm this hypothesis.
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Affiliation(s)
- Ma Paz Lorenzo
- Center for Metabolomics and Bioanalysis (CEMBIO), Facultad de Farmacia, Universidad CEU San Pablo, Madrid, Spain
| | - Danuta Dudzik
- Center for Metabolomics and Bioanalysis (CEMBIO), Facultad de Farmacia, Universidad CEU San Pablo, Madrid, Spain; Clinical Department of Perinatology, Public Clinic Hospital, Medical University of Bialystok, Bialystok, Poland
| | - Elena Varas
- Center for Metabolomics and Bioanalysis (CEMBIO), Facultad de Farmacia, Universidad CEU San Pablo, Madrid, Spain
| | - Manuel Gibellini
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 183, 41125 Modena, Italy
| | - Mariusz Skotnicki
- Clinical Department of Perinatology, Public Clinic Hospital, Medical University of Bialystok, Bialystok, Poland
| | - Marcin Zorawski
- Department of Pharmacology, Medical University of Bialystok, Bialystok, Poland
| | - Wieslaw Zarzycki
- Clinical Department of Endocrinology, Diabetology and Internal Diseases, Public Clinic Hospital, Medical University of Bialystok, Bialystok, Poland
| | - Federica Pellati
- Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 183, 41125 Modena, Italy
| | - Antonia García
- Center for Metabolomics and Bioanalysis (CEMBIO), Facultad de Farmacia, Universidad CEU San Pablo, Madrid, Spain.
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5
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Russell WR, Baka A, Björck I, Delzenne N, Gao D, Griffiths HR, Hadjilucas E, Juvonen K, Lahtinen S, Lansink M, Loon LV, Mykkänen H, östman E, Riccardi G, Vinoy S, Weickert MO. Impact of Diet Composition on Blood Glucose Regulation. Crit Rev Food Sci Nutr 2013; 56:541-90. [DOI: 10.1080/10408398.2013.792772] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Wendy R. Russell
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | | | - Inger Björck
- Centre for Chemistry and Chemical Engineering, University of Lund, Lund, Sweden
| | - Nathalie Delzenne
- Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Dan Gao
- Department of Diabetes and Metabolic Diseases, Beckman Research Institute of City of Hope, Duarte, California, USA
| | | | - Ellie Hadjilucas
- Coca-Cola Europe, Scientific and Regulatory Affairs Department, Brussels, Belgium
| | - Kristiina Juvonen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
| | | | - Mirian Lansink
- Danone Research, Centre for Specialised Nutrition, Wageningen, The Netherlands
| | - Luc Van Loon
- Department of Movement Sciences, Maastricht University, Maastricht, The Netherlands
| | - Hannu Mykkänen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
| | - Elin östman
- Centre for Chemistry and Chemical Engineering, University of Lund, Lund, Sweden
| | - Gabriele Riccardi
- Department of Clinical and Experimental Medicine, University Federico II, Naples, Italy
| | - Sophie Vinoy
- Kraft Foods, R&D Centre, Nutrition Department, Saclay, France
| | - Martin O. Weickert
- University Hospitals Coventry and Warwickshire and Division of Metabolic and Vascular Health, University of Warwick, Coventry, UK
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6
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Ktari N, Mnafgui K, Nasri R, Hamden K, Bkhairia I, Ben Hadj A, Boudaouara T, Elfeki A, Nasri M. Hypoglycemic and hypolipidemic effects of protein hydrolysates from zebra blenny (Salaria basilisca) in alloxan-induced diabetic rats. Food Funct 2013; 4:1691-9. [DOI: 10.1039/c3fo60264h] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Insulinotropic and muscle protein synthetic effects of branched-chain amino acids: potential therapy for type 2 diabetes and sarcopenia. Nutrients 2012. [PMID: 23201839 PMCID: PMC3509512 DOI: 10.3390/nu4111664] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The loss of muscle mass and strength with aging (i.e., sarcopenia) has a negative effect on functional independence and overall quality of life. One main contributing factor to sarcopenia is the reduced ability to increase skeletal muscle protein synthesis in response to habitual feeding, possibly due to a reduction in postprandial insulin release and an increase in insulin resistance. Branched-chain amino acids (BCAA), primarily leucine, increases the activation of pathways involved in muscle protein synthesis through insulin-dependent and independent mechanisms, which may help counteract the "anabolic resistance" to feeding in older adults. Leucine exhibits strong insulinotropic characteristics, which may increase amino acid availability for muscle protein synthesis, reduce muscle protein breakdown, and enhance glucose disposal to help maintain blood glucose homeostasis.
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Müller G, Schulz A, Hartz D, Dearey EA, Wetekam EM, Okonomopulos R, Crecelius A, Wied S, Frick W. Novel glimepiride derivatives with potential as double-edged swords against type II diabetes. Arch Physiol Biochem 2010; 116:3-20. [PMID: 20166804 DOI: 10.3109/13813450903575720] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sulphonylurea drugs have been widely used in the safe and efficacous therapy of type II diabetes during the past five decades. They lower blood glucose predominantly via the stimulation of insulin release from pancreatic beta-cells. However, a moderate insulin-independent regulation of fatty acid esterification and release in adipose tissue cells has been reported for certain sulphonylureas, in particular for glimepiride. On basis of the known pleiotropic pathogenesis of type II diabetes with a combination of beta-cell failure and peripheral, including adipocyte, insulin resistance, anti-diabetic drugs exerting both insulin releasing- and fatty acid-metabolizing activities in a more balanced and potent fashion may be of advantage. However, the completely different molecular mechanisms underlying the insulin-releasing and fatty acid-metabolizing activities, as have been delineated so far for glimepiride, may hamper their optimization within a single sulphonylurea molecule. By analyzing conventional sulphonylureas and novel glimepiride derivatives for their activities at the primary targets and downstream steps in both beta-cells and adipocytes in vitro we demonstrate here that the insulin-releasing and fatty acid-metabolizing activities are critically dependent on both overlapping and independent structural determinants. These were unravelled by the parallel losses of these two activities in a subset of glimepiride derivatives and the impairment in the insulin-releasing activity in parallel with elevation in the fatty acid-metabolizing activity in a different subset. Together these findings may provide a basis for the design of novel sulphonylureas with blood glucose-lowering activity relying on less pronounced stimulation of insulin release from pancreatic beta-cells and more pronounced insulin-independent stimulation of esterification as well as inhibition of release of fatty acids by adipocytes than provoked by the sulphonylureas currently used in therapy.
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Affiliation(s)
- Günter Müller
- Therapeutic Department Metabolism and Medicinal Chemistry, Frankfurt am Main, Germany.
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9
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Manders RJF, Wagenmakers AJM, Koopman R, Zorenc AHG, Menheere PPCA, Schaper NC, Saris WHM, van Loon LJC. Co-ingestion of a protein hydrolysate and amino acid mixture with carbohydrate improves plasma glucose disposal in patients with type 2 diabetes. Am J Clin Nutr 2005. [DOI: 10.1093/ajcn/82.1.76] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ralph JF Manders
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - Anton JM Wagenmakers
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - René Koopman
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - Antoine HG Zorenc
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - Paul PCA Menheere
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - Nicolaas C Schaper
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - Wim HM Saris
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
| | - Luc JC van Loon
- From the Departments of Human Biology (RJFM, RK, AHGZ, WHMS, and LJCvL) and Movement Sciences (LJCvL), the Nutrition and Toxicology Research Institute Maastricht (NUTRIM), the Maastricht University, Maastricht, Netherlands; the School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, United Kingdom (AJMW); and the Departments of Clinical Chemistry (PPCAM) and Internal Medicine
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10
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van Loon LJC, Kruijshoop M, Menheere PPCA, Wagenmakers AJM, Saris WHM, Keizer HA. Amino acid ingestion strongly enhances insulin secretion in patients with long-term type 2 diabetes. Diabetes Care 2003; 26:625-30. [PMID: 12610012 DOI: 10.2337/diacare.26.3.625] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Insulin secretion in response to carbohydrate intake is blunted in type 2 diabetic patients. However, it is not clear whether the insulin response to other stimuli, such as amino acids, is also diminished. Recently, we defined an optimal insulinoptropic mixture containing free leucine, phenylalanine, and a protein hydrolysate that substantially enhances the insulin response in healthy young subjects when coingested with carbohydrate. In this study, we aimed to investigate the insulinotropic capacity of this mixture in long-term type 2 diabetic patients. RESEARCH DESIGN AND METHODS Ten type 2 diabetic patients (aged 59.1 +/- 2.0 years, BMI 26.5 +/- 0.7 kg/m(2)) and 10 healthy control subjects (58.8 +/- 2.1 years, 26.5 +/- 0.7 kg/m(2)) visited our lab twice, during which insulin responses were determined following ingestion of carbohydrate only (CHO) or carbohydrate with the free amino acid/protein mixture (CHO+PRO). All subjects received 0.7 g x kg(-1) x h(-1) carbohydrate with or without 0.35 g x kg(-1) x h(-1) of the amino acid/protein mixture. RESULTS Insulin responses were dramatically increased in the CHO+PRO trial in both the type 2 diabetic and control groups (189 and 114%, respectively) compared with the CHO trial (P < 0.01). Plasma glucose, glucagon, growth hormone, cortisol, IGF-I, and IGF binding protein 3 responses were not different between trials within the 2-h time frame. CONCLUSIONS The insulin secretory capacity in long-term type 2 diabetic patients is substantially underestimated, as the insulin response following carbohydrate intake can be nearly tripled by coingestion of a free amino acid/protein mixture. Future research should be performed to investigate whether such nutritional interventions can improve postprandial glucose disposal.
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Affiliation(s)
- Luc J C van Loon
- Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, the Netherlands.
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11
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Hastedt K, Panten U. Inhibition of ATP-sensitive K(+)-channels by a sulfonylurea analogue with a phosphate group. Biochem Pharmacol 2003; 65:599-602. [PMID: 12566087 DOI: 10.1016/s0006-2952(02)01566-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hypoglycaemic sulfonylureas initiate insulin secretion by direct inhibition of ATP-sensitive K(+)-channels in the pancreatic beta-cells. These channels are composed of two proteins, a pore-forming subunit (K(IR)6.2 in the case of beta-cells) and a regulatory subunit, the sulfonylurea receptor (SUR). In the present study we characterised the interaction with SURs of the new sulfonylurea analogues 5-chloro-N-[2-(4-hydroxyphenyl)ethyl]-2-methoxybenzamide (compound I) and (4-[2-(5-chloro-2-methoxybenzamido)ethyl]phenyl)phosphate (compound II). Compounds I and II differ from the sulfonylurea analogue meglitinide only in so far as the carboxylic group of meglitinide is replaced by a hydroxyl group or a phosphate group, respectively. The binding affinities of compound II for the SUR subtypes SUR1 (identified in beta-cells) and SUR2A (identified in heart and skeletal muscle) were higher by 55 or 21-fold, respectively, than the corresponding affinities for compound I. In inside-out patch-clamp experiments compound II inhibited ATP-sensitive K(+)-channels of the SUR1/K(IR)6.2-type (characteristic of beta-cells) with an IC(50) value of 0.16 microM which is 6-fold lower than the corresponding value for meglitinide. These findings strongly support the conclusion that the interaction of sulfonylureas and acidic analogues with SURs is favoured by the anionic group of these drugs and that a phosphate group allows more efficient ligand interaction with SUR1 than a carboxylic group.
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Affiliation(s)
- Katja Hastedt
- Institute of Pharmacology and Toxicology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
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Gribble FM, Manley SE, Levy JC. Randomized dose ranging study of the reduction of fasting and postprandial glucose in type 2 diabetes by nateglinide (A-4166). Diabetes Care 2001; 24:1221-5. [PMID: 11423506 DOI: 10.2337/diacare.24.7.1221] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE This randomized crossover double-blind placebo-controlled study aimed to assess the efficacy of nateglinide (A-4166), a novel phenylalanine-derived insulin secretagogue, in type 2 diabetic subjects while fasting and 5 min before a standard meal. RESEARCH DESIGN AND METHODS A single dose of nateglinide (60, 120, or 180 mg) or placebo was given to eight diet-treated overnight-fasted type 2 diabetic patients and to seven patients 5 min before a standard breakfast. Plasma glucose, radioimmunoassay insulin, and nateglinide were measured at baseline and for a further 180 min. RESULTS The time-averaged 180-min postdose mean decrease in fasting plasma glucose concentration was greater after nateglinide (1.8 mmol/l; 95% CI 1.5-2.0) than after placebo (0.7 mmol/l; 95% CI 0.3-1.2) (P < 0.001). Hypoglycemia did not develop in any of the subjects. Insulin concentrations increased 1.5-, 1.8-, and 1.9-fold with the 60-, 120-, and 180-mg doses, respectively (P < 0.001), peaking approximately 30 min after the dose. Nateglinide concentrations peaked after approximately 30 min, decreasing to 21% of peak by 180 min. In the meal test, the mean increase (2.9 mmol/l, 2.3-3.6) in plasma glucose over 180 min after placebo was reduced by 1.8 mmol/l (P < 0.001) with the two higher doses of nateglinide. CONCLUSIONS A single dose of nateglinide administered to diet-treated type 2 diabetic patients with fasting hyperglycemia increased insulin secretion and reduced fasting glucose without hypoglycemia. Administered 5 min before a meal, nateglinide reduced the postprandial glucose excursion by 64%. With its rapid onset and short duration of action, nateglinide is a promising oral prandial therapy in type 2 diabetes.
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Affiliation(s)
- F M Gribble
- Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, UK
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Meyer M, Chudziak F, Schwanstecher C, Schwanstecher M, Panten U. Structural requirements of sulphonylureas and analogues for interaction with sulphonylurea receptor subtypes. Br J Pharmacol 1999; 128:27-34. [PMID: 10498831 PMCID: PMC1571605 DOI: 10.1038/sj.bjp.0702763] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The structure-activity relationship for hypoglycaemic sulphonylureas and analogues was examined. Binding affinities were compared using membranes from HIT-T15 cells (beta-cell line) and from COS-7 cells transiently expressing sulphonylurea receptor subtypes (SUR1, SUR2A and SUR2B). Inhibition of adenosine-triphosphate-sensitive K+ channels (KATP-channels) was measured in mouse pancreatic beta-cells. 2. The tested compounds displayed similar binding affinities for SUR2A and SUR2B. 3. Meglitinide (benzoic acid derivative) bound to SUR1 and the SUR2 isoforms with similar affinities. Replacement of the carboxyl group of meglitinide by a methyl group significantly decreased the binding affinities for SUR1 and the SUR2 isoforms (>4 fold) and the potency to inhibit KATP-channel activity of beta-cells (24 fold). Replacement of the carboxyl group of meglitinide by a sulphonylurea group significantly increased the affinities for SUR1 (5 fold) and the SUR2 isoforms (13 - 16 fold). 4. Glibenclamide bound to the SUR2 isoforms with 300 - 500 fold lower affinity than to SUR1. Exchanging the cyclohexyl ring of glibenclamide by a methyl group or removal of the lipophilic side chain of glibenclamide (5-chloro-2-methoxy-benzamidoethyl chain) markedly reduced but did not abolish the selectivity for SUR1. 5. In conclusion, interaction of sulphonylureas and acidic analogues with SUR1, SUR2A and SUR2B is favoured by the anionic group of these drugs. Hypoglycaemic sulphonylureas (e.g. glibenclamide) owe selectivity for SUR1 to lipophilic substitution on their urea group. Sulphonylureas without lipophilic substitution on the urea group could represent lead compounds for the development of SUR2-selective drugs.
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Affiliation(s)
- Miriam Meyer
- Institute of Pharmacology and Toxicology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Franz Chudziak
- Institute of Pharmacology and Toxicology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Christina Schwanstecher
- Institute of Pharmacology and Toxicology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Mathias Schwanstecher
- Institute of Pharmacology and Toxicology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
| | - Uwe Panten
- Institute of Pharmacology and Toxicology, Technical University of Braunschweig, Mendelssohnstrasse 1, D-38106 Braunschweig, Germany
- Author for correspondence:
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