Impaired first-phase insulin response predicts postprandial blood glucose increment in patients with recently diagnosed type 2 diabetes.
OBJECTIVE
The aim of the study was to evaluate the relationship between postprandial blood glucose and first-phase insulin response and, furthermore, to assess whether the intravenous glucagon stimulation test can be used as a predictor for increased postprandial glucose in patients with recently diagnosed type 2 diabetes.


METHODS
Twenty patients with diet-treated type 2 diabetes, diagnosed within the past 5 years, were included. In random order, on three different days, the patients underwent: 1) a standardized meal tolerance test, 2) an intravenous glucose tolerance test, and 3) an intravenous glucagon stimulation test. The postprandial blood glucose response was defined as the incremental area under the blood glucose curve 0-240 min after the meal.


RESULTS
The first-phase insulin response at an intravenous glucose stimulation test was significantly correlated to the postprandial blood glucose increment (R(2)=0.21, p<0.05) and the maximal increment in plasma glucose concentration (R(2)=0.40, p<0.01) during the meal tolerance test. However, the incremental C-peptide value at 6 min in response to intravenous glucagon stimulation did not correlate to the postprandial blood glucose increment (R(2)=0.09, p=0.14).


CONCLUSIONS
Impaired first-phase insulin response is a significant predictor of the increase in postprandial blood glucose in patients with type 2 diabetes in near normal metabolic control, whereas beta-cell function, assessed by glucagon stimulation test, is not.
Gredal
C
C
Department of Internal Medicine and Clinical Pharmacology, Gentofte University Hospital, Hellerup, Denmark. c.gredal@dadlnet.dk
Rosenfalck
A M
AM
Dejgaard
A
A
Hilsted
J
J
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D005934:Glucagon / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000517:prevention & control; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D011237:Predictive Value of Tests; D012016:Reference Values; D012680:Sensitivity and Specificity
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D005934:Glucagon