Assessment The Function Of Islet α-cell And β-cell In Gestational Diabetic Patients During Mid Pregnancy

Objective To investigate relationship between islet a-cell and (3-cell function and gestational diabetes mellitus (GDM) during mid pregnancy.Methods Based on the result of oral75-g glucose tolerance test(OGTT),a total of55pregnant women in the second trimester (24-28weeks) were selected and divided into GDM group (n=25) and normal glucose tolerance (NGT) group (n=30). Glycemic,insulin and glucagon values at each time point of the OGTT, blood lipid,and also blood pressure,body height were measured.Body weight before pregnancy were asked and body mass index(BMI) were calculated.The differences of the values mensioned above and parameters for islet a-cell andβ-cell function were compared between the two groups.Results Women with GDM were significantly older than those in NGT group. Mean glycemic and insulin values at each time point of the OGTT, incremental area under the glucose curve(AUCGW)and insulin curve (AUCNS) during the OGTT, basic insulin secretion index(HOMA-P)were significantly higher compared with those in NGDM group (P<0.05),however, in GDM group, dynamic insulin secretion index(Stumvoll1-and2-phase insulin secretion index), insulin sensitivity index(ISI-Matsuda), insulin secretion-sensitivity index(ISSI) were reduced (P<0.05), AUCNS/AUCGW too was significantly reduced(P<0.01). Mean glucagon values at each time point of the OGTT and incremental area under the glucagon curve(AUCGL)tended downward, but there were no significant differences in the two groups(P>0.05). Multiple linear regression analysis showed that ISI-Matsuda, ISSI, HOMA-β, Stumvoll1-and2-phase insulin secretion index accounting partially for the change of the plasma glucose and ISI-Matsuda was the most important one among them.Conclusions The function of islet a-cell is normal while the function of β-cell is impaired in the patients with GDM, and insulin secretion failing to compensate insulin resistance is the main reason for GDM.