The glucose-lowering alpha-glucosidase inhibitor acarbose, is believed to act by delaying digestion and absorption of dietary carbohydrates. It has been shown that acarbose increases circulating glucagon-like peptide 1 (GLP-1). Using the GLP-1 receptor antagonist exendin(9-39)NH2, we investigated the effect of acarbose-induced GLP-1 secretion on postprandial glucose metabolism in patients with type 2 diabetes (T2D). In a double-blinded, placebo-controlled, randomized, cross-over study, 15 participants with metformin-treated T2D (age 57-85 years, BMI 23.6-34.6 kg/m2, HbA1c 40-74 mmol/mol (5.8-8.9%)) were subjected to two 14-day treatment periods with acarbose (uptitrated to 100 mg TID) and placebo treatment, respectively, with an interposed 6-week wash-out period. At the end of each treatment period, we performed two randomized 4-hour mixed meal tests (including acetaminophen for evaluation of gastric emptying) with concomitant infusion of exendin(9-39)NH2 (1000 pmol/kg/min for 20 min followed by 450 pmol/kg/min for 240 min) and saline, respectively. Acarbose treatment lowered fasting plasma glucose (P<0.0001) and postprandial plasma glucose excursions (P<0.0001) compared to placebo. Furthermore, acarbose almost doubled the postprandial GLP-1 response (P=0.0032), reduced postprandial glucose-dependent insulinotropic polypeptide (P<0.0001) and delayed gastric emptying (P=0.0395). No absolute difference was seen in exendin(9-39)NH2-induced postprandial plasma glucose changes between treatment periods (P=0.54), but relative to postprandial glucose tolerance during exendin(9-39)NH2 infusions, the change (i.e., contribution of GLP-1) was significantly higher during acarbose (56±26%) compared to placebo treatment (37±15%) (P=0.042). We conclude that acarbose treatment robustly stimulates GLP-1 secretion in patients with T2D and that acarbose-induced GLP-1 secretion contributes to the glucose-lowering effect of acarbose.
N.B. Dalsgaard: None. L.S. Gasbjerg: Stock/Shareholder; Self; Antag Therapeutics. L.S. Hansen: None. N.L. Hansen: None. S. Stensen: None. B. Hartmann: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. T. Vilsbøll: None. F.K. Knop: Advisory Panel; Self; AstraZeneca, MedImmune, Merck Sharp & Dohme Corp., Mundipharma, Novo Nordisk A/S, Sanofi. Consultant; Self; Amgen Inc., Carmot Therapeutics, Novo Nordisk A/S. Research Support; Self; AstraZeneca, Novo Nordisk A/S. Speaker's Bureau; Self; AstraZeneca, MedImmune, Merck Sharp & Dohme Corp., Mundipharma, Norgine, Novo Nordisk A/S.