TY - JOUR
T1 - Oral glutamine increases circulating glucagon-like peptide 1, glucagon, and insulin concentrations in lean, obese, and type 2 diabetic subjects
AU - Greenfield, Jerry R
AU - Farooqi, I Sadaf
AU - Keogh, Julia M
AU - Henning, Elana
AU - Habib, Abdella M
AU - Blackwood, Anthea
AU - Reimann, Frank
AU - Holst, Jens J
AU - Gribble, Fiona M
N1 - Keywords: Administration, Oral; Adult; Area Under Curve; Blood Glucose; Cross-Over Studies; Diabetes Mellitus, Type 2; Female; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose Tolerance Test; Glutamine; Humans; Insulin; Male; Obesity; Thinness
PY - 2008
Y1 - 2008
N2 - BACKGROUND: Incretin hormones, such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), play an important role in meal-related insulin secretion. We previously demonstrated that glutamine is a potent stimulus of GLP-1 secretion in vitro. OBJECTIVE: Our objective was to determine whether glutamine increases circulating GLP-1 and GIP concentrations in vivo and, if so, whether this is associated with an increase in plasma insulin. DESIGN: We recruited 8 healthy normal-weight volunteers (LEAN), 8 obese individuals with type 2 diabetes or impaired glucose tolerance (OB-DIAB) and 8 obese nondiabetic control subjects (OB-CON). Oral glucose (75 g), glutamine (30 g), and water were administered on 3 separate days in random order, and plasma concentrations of GLP-1, GIP, insulin, glucagon, and glucose were measured over 120 min. RESULTS: Oral glucose led to increases in circulating GLP-1 concentrations, which peaked at 30 min in LEAN (31.9 +/- 5.7 pmol/L) and OB-CON (24.3 +/- 2.1 pmol/L) subjects and at 45 min in OB-DIAB subjects (19.5 +/- 1.8 pmol/L). Circulating GLP-1 concentrations increased in all study groups after glutamine ingestion, with peak concentrations at 30 min of 22.5 +/- 3.4, 17.9 +/- 1.1, and 17.3 +/- 3.4 pmol/L in LEAN, OB-CON, and OB-DIAB subjects, respectively. Glutamine also increased plasma GIP concentrations but less effectively than glucose. Consistent with the increases in GLP-1 and GIP, glutamine significantly increased circulating plasma insulin concentrations. Glutamine stimulated glucagon secretion in all 3 study groups. CONCLUSION: Glutamine effectively increases circulating GLP-1, GIP, and insulin concentrations in vivo and may represent a novel therapeutic approach to stimulating insulin secretion in obesity and type 2 diabetes.
AB - BACKGROUND: Incretin hormones, such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), play an important role in meal-related insulin secretion. We previously demonstrated that glutamine is a potent stimulus of GLP-1 secretion in vitro. OBJECTIVE: Our objective was to determine whether glutamine increases circulating GLP-1 and GIP concentrations in vivo and, if so, whether this is associated with an increase in plasma insulin. DESIGN: We recruited 8 healthy normal-weight volunteers (LEAN), 8 obese individuals with type 2 diabetes or impaired glucose tolerance (OB-DIAB) and 8 obese nondiabetic control subjects (OB-CON). Oral glucose (75 g), glutamine (30 g), and water were administered on 3 separate days in random order, and plasma concentrations of GLP-1, GIP, insulin, glucagon, and glucose were measured over 120 min. RESULTS: Oral glucose led to increases in circulating GLP-1 concentrations, which peaked at 30 min in LEAN (31.9 +/- 5.7 pmol/L) and OB-CON (24.3 +/- 2.1 pmol/L) subjects and at 45 min in OB-DIAB subjects (19.5 +/- 1.8 pmol/L). Circulating GLP-1 concentrations increased in all study groups after glutamine ingestion, with peak concentrations at 30 min of 22.5 +/- 3.4, 17.9 +/- 1.1, and 17.3 +/- 3.4 pmol/L in LEAN, OB-CON, and OB-DIAB subjects, respectively. Glutamine also increased plasma GIP concentrations but less effectively than glucose. Consistent with the increases in GLP-1 and GIP, glutamine significantly increased circulating plasma insulin concentrations. Glutamine stimulated glucagon secretion in all 3 study groups. CONCLUSION: Glutamine effectively increases circulating GLP-1, GIP, and insulin concentrations in vivo and may represent a novel therapeutic approach to stimulating insulin secretion in obesity and type 2 diabetes.
U2 - 10.3945/ajcn.2008.26362
DO - 10.3945/ajcn.2008.26362
M3 - Journal article
C2 - 19056578
SN - 0002-9165
VL - 89
SP - 106
EP - 113
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
IS - 1
ER -
