et al. 2014 ) or indirectly through stimulation of the secretion of glucagon-like peptide-1 (GLP-1) from intestinal endocrine cells ( Mizokami et al. 2013 , 2014 ). GLP-1 is a member of the incretin family of hormones that are secreted from
Akiko Mizokami, Satoru Mukai, Jing Gao, Tomoyo Kawakubo-Yasukochi, Takahito Otani, Hiroshi Takeuchi, Eijiro Jimi, and Masato Hirata
Christian Hölscher
Introduction The main hallmark of type 2 diabetes mellitus (T2DM) is insulin desensitisation. The discovery that the incretin hormone glucagon-like peptide 1 (GLP-1) facilitates insulin release during episodes of hyperglycaemia and has several
Eun Young Lee, Shuji Kaneko, Promsuk Jutabha, Xilin Zhang, Susumu Seino, Takahito Jomori, Naohiko Anzai, and Takashi Miki
Introduction Oral ingestion of nutrients triggers the secretion of gut hormones from various enteroendocrine cells ( Ezcurra et al . 2013 , Cho et al . 2014 ). Among these, glucagon-like peptide 1 (GLP1) and glucose-dependent insulinotropic
Berit Svendsen, Ramona Pais, Maja S Engelstoft, Nikolay B Milev, Paul Richards, Charlotte B Christiansen, Kristoffer L Egerod, Signe M Jensen, Abdella M Habib, Fiona M Gribble, Thue W Schwartz, Frank Reimann, and Jens J Holst
Introduction The incretin hormones, glucagon-like peptide-1 (GLP1) and glucose-dependent insulinotropic polypeptide (GIP) strongly potentiate postprandial insulin secretion and are therefore important regulators of glucose homeostasis. They are
Paul Millar, Nupur Pathak, Vadivel Parthsarathy, Anthony J Bjourson, Maurice O’Kane, Varun Pathak, R Charlotte Moffett, Peter R Flatt, and Victor A Gault
surge in the number of new drug classes such as glucagon-like peptide-1 (GLP-1) agonists, dipeptidylpeptidase-4 (DPP4) inhibitors and sodium glucose cotransporter-2 (SGLT2) inhibitors ( Bailey et al . 2016 ). Although these agents may be used as
Yingxin Xian, Zonglan Chen, Hongrong Deng, Mengyin Cai, Hua Liang, Wen Xu, Jianping Weng, and Fen Xu
visceral omental fat in subjects with obesity exhibit severely impaired endothelium-dependent vasodilation ( Farb et al. 2012 ). Clinical studies demonstrated that exenatide, a glucagon-like peptide 1 (GLP-1) receptor agonist, improved glycemic control
Rebecca McGirr, Leonardo Guizzetti, and Savita Dhanvantari
al . 1994 , Furuta et al . 2001 ). By contrast, proglucagon is processed to glucagon-like peptide (GLP)-1 and GLP-2 in the intestine and brain by PC1/3 ( Dhanvantari et al . 1996 , Dhanvantari & Brubaker 1998 , Damholt et al . 1999 ). Glucagon
J C Parker, K S Lavery, N Irwin, B D Green, B Greer, P Harriott, F P M O’Harte, V A Gault, and P R Flatt
Introduction Glucose-dependent insulinotrophic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are important gastrointestinal-releasing hormones involved in the regulation of postprandial nutrient homeostasis ( Meier et al
G Üçkaya, P Delagrange, A Chavanieu, G Grassy, M-F Berthault, A Ktorza, E Cerasi, G Leibowitz, and N Kaiser
that aim to improve β-cell function and survival. Glucagon-like peptide 1 (GLP-1) is a potent incretin hormone secreted by the intestinal L cells in response to food intake ( Drucker 2001 ). GLP-1 exerts multiple effects on pancreatic β
MA Luque, N Gonzalez, L Marquez, A Acitores, A Redondo, M Morales, I Valverde, and ML Villanueva-Penacarrillo
Glucagon-like peptide-1 (GLP-1) has been shown to have insulin-like effects upon the metabolism of glucose in rat liver, muscle and fat, and on that of lipids in rat and human adipocytes. These actions seem to be exerted through specific receptors which, unlike that of the pancreas, are not - at least in liver and muscle - cAMP-associated. Here we have investigated the effect, its characteristics, and possible second messengers of GLP-1 on the glucose metabolism of human skeletal muscle, in tissue strips and primary cultured myocytes. In muscle strips, GLP-1, like insulin, stimulated glycogen synthesis, glycogen synthase a activity, and glucose oxidation and utilization, and inhibited glycogen phosphorylase a activity, all of this at physiological concentrations of the peptide. In cultured myotubes, GLP-1 exerted, from 10(-13) mol/l, a dose-related increase of the D-[U-(14)C]glucose incorporation into glycogen, with the same potency as insulin, together with an activation of glycogen synthase a; the effect of 10(-11) mol/l GLP-1 on both parameters was additive to that induced by the equimolar amount of insulin. Synthase a was still activated in cells after 2 days of exposure to GLP-1, as compared with myotubes maintained in the absence of peptide. In human muscle cells, exendin-4 and its truncated form 9-39 amide (Ex-9) are both agonists of the GLP-1 effect on glycogen synthesis and synthase a activity; but while neither GLP-1 nor exendin-4 affected the cellular cAMP content after 5-min incubation in the absence of 3-isobutyl-1-methylxantine (IBMX), an increase was detected with Ex-9. GLP-1, exendin-4, Ex-9 and insulin all induced the prompt hydrolysis of glycosylphosphatidylinositols (GPIs). This work shows a potent stimulatory effect of GLP-1 on the glucose metabolism of human skeletal muscle, and supports the long-term therapeutic value of the peptide. Further evidence for a GLP-1 receptor in this tissue, different from that of the pancreas, is also illustrated, suggesting a role for an inositolphosphoglycan (IPG) as at least one of the possible second messengers of the GLP-1 action in human muscle.
