Glutamine reduces postprandial glycemia and augments the glucagon-like peptide-1 response in type 2 diabetes patients

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Dorit Samocha-Bonet, Olivia Wong, Emma-Leigh Synnott, Naomi Piyaratna, Ashley Douglas, Fiona M Gribble, Jens Juul Holst, Donald J Chisholm, Jerry R Greenfield

Impaired glucagon-like peptide (GLP-1) secretion or response may contribute to ineffective insulin release in type 2 diabetes. The conditionally essential amino acid glutamine stimulates GLP-1 secretion in vitro and in vivo. In a randomized, crossover study, we evaluated the effect of oral glutamine, with or without sitagliptin (SIT), on postprandial glycemia and GLP-1 concentration in 15 type 2 diabetes patients (glycated hemoglobin 6.5 ± 0.6%). Participants ingested a low-fat meal (5% fat) after receiving either water (control), 30 g l-glutamine (Gln-30), 15 g L-glutamine (Gln-15), 100 mg SIT, or 100 mg SIT and 15 g L-glutamine (SIT+Gln-15). Studies were conducted 1-2 wk apart. Blood was collected at baseline and postprandially for 180 min for measurement of circulating glucose, insulin, C-peptide, glucagon, and total and active GLP-1. Gln-30 and SIT+Gln-15 reduced the early (t = 0-60 min) postprandial glycemic response compared with control. All Gln treatments enhanced the postprandial insulin response from t = 60-180 min but had no effect on the C-peptide response compared with control. The postprandial glucagon concentration was increased by Gln-30 and Gln-15 compared with control, but the insulin:glucagon ratio was not affected by any treatment. In contrast to Gln-30, which tended to increase the total GLP-1 AUC, SIT tended to decrease the total GLP-1 AUC relative to control (both P = 0.03). Gln-30 and SIT increased the active GLP-1 AUC compared with control (P = 0.008 and P = 0.01, respectively). In summary, Gln-30 decreased the early postprandial glucose response, enhanced late postprandial insulinemia, and augmented postprandial active GLP-1 responses compared with control. These findings suggest that glutamine may be a novel agent for stimulating GLP-1 concentration and limiting postprandial glycemia in type 2 diabetes.
Original languageEnglish
JournalJournal of Nutrition
Volume141
Issue number7
Pages (from-to)1233-1238
Number of pages6
ISSN0022-3166
DOIs
Publication statusPublished - Jul 2011

    Research areas

  • Administration, Oral, Aged, Blood Glucose, C-Peptide, Cross-Over Studies, Diabetes Mellitus, Type 2, Female, Gastric Emptying, Glucagon, Glucagon-Like Peptide 1, Glutamine, Humans, Hyperglycemia, Insulin, Male, Middle Aged, Postprandial Period, Pyrazines, Triazoles

ID: 38531687