SIGNIFICANT HYPERINSULINEMIA IN NEW-ONSET TYPE-2 DIABETES

Patients and method: Since this has therapeutical implications, ten pa tients were identified with new-onset type 2 diabetes, defined by fast ing blood glucose concentrations below 120 mg/dl, no previous history of diabetes and venous blood glucose concentrations at 120 min of an o ral glucose tolerance test above 200 mg/dl (x 262 +/- 15 mg/dl) (''dia betic glucose tolerance''). Ten subjects with normal glucose tolerance and no familial history olNIDDM, who were matched for gender, age (n: 56 +/- 2 years, D: 61 +/- 5) and BMI (n: 28 +/- 1, D: 28 +/- 1), serv ed as control group. Serum insulin was measured using a double-antibod y sandwich-rest (no cross-reaction with proinsulin and C-peptide) at 0 , 30 and 120 min of an oGTT. Result: In the diabetic group, basal insu lin levels were found to be elevated 1.7-fold (n: 7.9 +/- 1.4 uU/ml, D : 13.3 +/- 1.4, p = 0.03), 30 min values were the same in both groups and the 120 min value war 4.6-fold higher in the diabetic group (n: 33 .9 +/- 8.7, D: 156.2 +/- 27.4, p = 0.0008). Conclusion: Thus, in new-o nset diabetes, in the early phase of an oGTT (30 min) both insulin sec retion and action are reduced, in the second phase (120 min) severe in sulin resistance predominates at maximally stimulated secretion. These findings underline the therapeutical strategy in these patients, to r educe postprandial blood glucose increments and improve insulin resist ance by diet and, if necessary, pharmacologically.