The Changes Of The Serum True Insulin And Proinsulin Level And Their Significances In Obese, Impaired Glucose Tolerance And Type 2 Diabetic Patients

Objective To study the changes and their significance of serum true insulin (TI)and proinsulin (PI) in obese > impaired glucose tolerance (IGT) and type 2 diabetic patients(2-DM). Methods 23 cases with normal glucose tolerance (NOT), 35 cases with impaired glucose tolerance and 25 cases with type 2 diabetic patients were subdivided into obese and non-obese groups. Serum TI and PI were measured by RIA using monoclonal antibody with no significant cross-reaction between ture insulin and proinsulin .IRI was measured by RIA.Result The areas under the curve of the IRI and TI had significantly difference between the obese group with IGT and non-obese group with NGT, so was between tiie obese group with 2-DM and the non-obese group with NGT. The areas under the curve of the PI and PI/(PI盩I) ratio of the obese group and non-obese group with 2-DM and IGT were higher than those of the non-obese group with NGT, and also had significant difference between the group with IGT and the group with 2-DM. IS and ISI of the non-obese group with NGT were significantly higher than the group with 2-DM and IGT. After regulated the effect of the ISI, mere still had significant negtive correlation between the areas under the curve of the PI and IS. Conclusion The individuals with obese IGT, obese type2-DM have insulin resistance and functional defect of the islet bete-cell. The patients with type 2-DM have increased PI level and PI/(PI+TI) ratio. To some extent, PI can estimate the function of the islet beta-cell. 71 is better than IRI in elevating the insulin resistance and the function of the bete-cell.