Fig. 1The indexes for (A) insulin sensitivity (SI) and (B) basal, (C) dynamic, (D) static and (E) total β-cell responsivity (Φb, Φd, Φs, and Φt), (F) basal hepatic insulin extraction ratio (HEb), and (G) post-glucose challenge hepatic insulin extraction ratio (HEpost). The Mann-Whitney test was used to compare the indexes between the groups. NGT, normal glucose tolerance; T2DM, type 2 diabetes mellitus; NS, not significant.
Fig. 2The (A) dynamic, (B) static, and (C) total disposition indexes (DId, DIs, and DIt) in the patients with type 2 diabetes mellitus (T2DM) and individuals with normal glucose tolerance (NGT). The Mann-Whitney test was used to compare the indexes between the groups.
Fig. 3Distribution of insulin sensitivity and secretion in the patients with type 2 diabetes (T2DM) and individuals with normal glucose tolerance (NGT). The hyperbolae for the (A) dynamic, (B) static, (C) and total disposition (DIs, DId, and DIt) indexes are shown for the NGT group (black line and open black circles) and the T2DM group (gray line and open gray circles) with a DI metric. Each circle or square represents a single subject. The subjects in each group presumably share the same disposition index, and a tendency toward the leftward and downward positioning in the T2DM patients can be observed. Φd, dynamic; Φs, static; Φt, total β-cell responsivity.
Fig. 4Correlation analyses between the indexes obtained in the oral minimal model and other indexes of insulin secretion or insulin sensitivity (SI). Spearman correlation analysis was used. Correlations of (A) dynamic (Φd) and (B) static β-cell responsivity (Φs) with postprandial C-peptide to glucose ratio (PCGR) are shown. Correlations of insulin sensitivity (SI) with (C) Matsuda index and (D) homeostasis model assessment of insulin resistance (HOMA-IR) are shown.
Table 1Clinical characteristics of the subjects
Characteristic |
NGT (n=10) |
T2DM (n=14) |
P value |
Sex, male/female |
8/2 |
9/5 |
0.653 |
Age, yr |
39.8±13.5 |
53.8±9.4 |
0.019 |
Body weight, kg |
66.6±15.0 |
67.6±14.4 |
0.898 |
Body mass index, kg/m2
|
22.9±3.5 |
24.5±3.5 |
0.403 |
Duration of diabetes mellitus, yr |
NA |
4.7±2.4 |
NA |
Fasting plasma glucose, mg/dL |
92.0±4.5 |
146.2±27.6 |
<0.001 |
Peak plasma glucose, mg/dL |
175.9±17.1 |
337.0±49.5 |
<0.001 |
Time for peak glucose, min |
49.0±13.5 |
93.6±18.9 |
<0.001 |
PCGR |
2.6±0.6 |
1.3±0.4 |
<0.001 |
Matsuda index |
8.8±3.3 |
5.5±2.8 |
0.002 |
HOMA-IR |
1.2±1.1 |
2.3±1.3 |
0.002 |