Assessment of beta-cell function in young patients with type 2 diabetes: arginine-stimulated insulin secretion may reflect beta-cell reserve.

OBJECTIVE: Simple methods for the evaluation of dynamic b-cell function in epidemiological and clinical studies of patients with type 2 diabetes (T2D) are needed. The aim of this study was to evaluate the dynamic beta-cell function in young patients with T2D with different disease durations and treatments.
METHODS: Overall, 54 subjects with T2D from the Diabetes Incidence Study in Sweden (DISS) and 23 healthy control participants were included in this cross-sectional study. Beta-cell function was assessed by intravenous (i.v.) administration of arginine followed by i.v. glucose. The acute insulin and C-peptide responses to arginine (AIRarg and Ac-pepRarg, respectively) and to glucose (AIRglu and Ac-pepRglu, respectively)were estimated.Homeostasis model assessment of b-cell function(HOMA-b) andCpeptide assessments were also used for comparisons between patients with T2D and control participants.
RESULTS: AIRarg and Ac-pepRarg, but not AIRglu and Ac-pepRglu, could differentiate between patients with different disease durations. AIRglu values were 89% (P < 0.001) lower and AIRarg values were 29% (P < 0.01) lower in patients with T2D compared with control participants. HOMA-b and fasting plasma C-peptide levels did not differ between the T2D and control groups.
CONCLUSION: In young patients with T2D, the insulin secretory response to i.v. glucose is markedly attenuated, whereas i.v. arginine-stimulated insulin release is better preserved and can distinguish between patients with different disease duration and antidiabetic therapies. This suggests that the i.v. arginine stimulation test may provide an estimate of functional beta-cell reserve.