title: Immediate enhancement of first-phase insulin secretion and unchanged glucose effectiveness in patients with type 2 diabetes after Roux-en-Y gastric bypass.
abstract: Roux-en-Y gastric bypass surgery (RYGB) in patients with type 2 diabetes often leads to early disease remission, and it is unknown to what extent this involves improved pancreatic β-cell function per se and/or enhanced insulin- and non-insulin-mediated glucose disposal (glucose effectiveness). We studied 30 obese patients, including 10 with type 2 diabetes, 8 with impaired glucose tolerance, and 12 with normal glucose tolerance before, 1 wk, and 3 mo after RYGB, using an intravenous glucose tolerance test (IVGTT) to estimate first-phase insulin response, insulin sensitivity (Si), and glucose effectiveness with Bergman's minimal model. In the fasting state, insulin sensitivity was estimated by HOMA-S and β-cell function by HOMA-β. Moreover, mixed-meal tests and oral GTTs were performed. In patients with type 2 diabetes, glucose levels normalized after RYGB, first-phase insulin secretion in response to iv glucose increased twofold, and HOMA-β already improved 1 wk postoperatively, with further enhancements at 3 mo. Insulin sensitivity increased in the liver (HOMA-S) at 1 wk and at 3 mo in peripheral tissues (Si), whereas glucose effectiveness did not improve significantly. During oral testing, GLP-1 responses and insulin secretion increased regardless of glucose tolerance. Therefore, in addition to increased insulin sensitivity and exaggerated postprandial GLP-1 levels, diabetes remission after RYGB involves early improvement of pancreatic β-cell function per se, reflected in enhanced first-phase insulin secretion to iv glucose and increased HOMA-β. A major role for improved glucose effectiveness after RYGB was not supported by this study.
authors: Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark;
authors: Christoffer
authors: http://orcid.org/0000-0002-7210-0807
authors: C
authors: Martinussen
authors: Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark;
authors: Kirstine N
authors: KN
authors: Bojsen-Møller
authors: Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark;
authors: Carsten
authors: C
authors: Dirksen
authors: Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark;
authors: Siv H
authors: SH
authors: Jacobsen
authors: Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark;
authors: Nils B
authors: NB
authors: Jørgensen
authors: Department of Surgical Gastroenterology, Hvidovre Hospital, Hvidovre, Denmark.
authors: Viggo B
authors: VB
authors: Kristiansen
authors: Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; and.
authors: Jens J
authors: JJ
authors: Holst
authors: Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark; sten.madsbad@regionh.dk.
authors: Sten
authors: S
authors: Madsbad
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001835:Body Weight / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000601:surgery*; D005215:Fasting / Q000378:metabolism; D015390:Gastric Bypass / Q000534:rehabilitation; D018149:Glucose Intolerance / Q000378:metabolism / Q000601:surgery; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism / Q000601:surgery; D011184:Postoperative Period
chemical_list: D001786:Blood Glucose; D007328:Insulin
keywords: first-phase insulin secretion; glucose effectiveness; insulin sensitivity; type 2 diabetes; β-cell function