title: Dipeptidyl peptidase-4 inhibitor (vildagliptin) improves glycemic control after meal tolerance test by suppressing glucagon release.
abstract: OBJECTIVE
  We aimed to evaluate changes in insulin and glucagon secretion, as well as glucose levels, with a meal tolerance test (MTT) before and after 6 months of treatment with vildagliptin in a clinical setting.
  
  
  METHODS
  Participants were 15 patients with uncontrolled type 2 diabetes mellitus (glycated hemoglobin [HbA1c] over 6.9% for more than 3 months). MTTs were conducted before and 6 months after addition of vildagliptin (50 mg twice daily [bid]). Blood samples were collected immediately before, and 1 and 2 h after the test meal for measurement of blood glucose concentration, immune-reactive insulin (IRI), and glucagon. HbA1c was measured at 6 months.
  
  
  RESULTS
  Mean age of participants was 55.5 ± 2.8 years, and ten (66.7%) were male. Mean HbA1c significantly improved from 7.6 to 6.8% at 6 months after addition of vildagliptin. Blood glucose at 1 and 2 h after the test meal was significantly reduced after addition of vildagliptin, while the reduction in glucagon showed borderline significance and IRI showed no difference. In a comparison of blood glucose-related parameters between subgroups based on median glucose change in area under the curve during MTT (ΔAUC0-2h), glucagon ΔAUC0-2h was significantly lower in the group with more improved glucose levels (ΔAUC0-2h ≥65 mg/dL), but that of IRI did not differ.
  
  
  CONCLUSIONS
  Suppression of glucagon release by vildagliptin may improve glycemic control without increasing insulin levels in patients with type 2 diabetes.
authors.affiliation: OKM Okamoto Medical Clinic, Tokyo, Japan.
authors.forename: Aki
authors.initials: A
authors.lastname: Okamoto
authors.forename: Hirohide
authors.initials: H
authors.lastname: Yokokawa
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sanada
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D001786:Blood Glucose / Q000187:drug effects*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005502:Food; D005934:Glucagon / Q000097:blood / Q000378:metabolism*; D006442:Glycated Hemoglobin / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009570:Nitriles / Q000494:pharmacology* / Q000627:therapeutic use; D011759:Pyrrolidines / Q000494:pharmacology* / Q000627:therapeutic use; D000077597:Vildagliptin
chemical_list: D000218:Adamantane; D001786:Blood Glucose; D054873:Dipeptidyl-Peptidase IV Inhibitors; D005934:Glucagon; D006442:Glycated Hemoglobin; D007328:Insulin; D009570:Nitriles; D011759:Pyrrolidines; D000077597:Vildagliptin; C517652:hemoglobin A1c protein, human