Functional assessment of islet α-cell and β-cell in patients with gestational diabetes mellitus

Abstract

Based on the result of oral 75 g glucose tolerance test (OGTT),55 pregnant women during the second trimester (gestational age 24-28 weeks) were selected and divided into gestational diabetes mellitus (GDM)group (n =25) and normal glucose tolerance (NGT) group (n =30).Women with GDM were older than those in NGT group.Blood glucose and insulin levels during the OGTT,incremental area under the glucose curve (AUCGLU) and insulin curve (AUCINs) during the OGTT,and basic insulin secretion index (HOMA-β) in the GDM group were higher compared with those in NGT group (P＜0.05).However,in GDM group,insulin sensitivity index (ISI-Matsuda),dynamic insulin secretion index(Stumvoll 1-and 2-phase insulin secretion indices),and insulin secretion-sensitivity index (ISSI)were lowered (all P＜ 0.05),so was AUCINS/AUCGLU (P ＜ 0.01),as compared with those in NGT group.Blood glucagon levels during OGTF and incremental area under the glucagon curve (AUCGL) showed no significant differences between 2 groups (P ＞ 0.05).Multiple linear regression analysis showed that ISI-Matsuda,ISSI,HOMA-β,Stumvoll 1-and 2-phase insulin secretion indices accounted partially for the change of plasma glucose and ISI-Matsuda was the most important one among them.The function of islet α-cell seems to be normal while the function of β-cell is impaired in the patients with GDM,and failure of insulin secretion to overcome insulin resistance is the main reason for GDM. Key words: Diabetes mellitus, gestational; Insulin resistance; α-cell function; β-cell function