Table 1.
Clinical characteristics of human subjects
| Rd ≥ 10 (n = 21) | Rd (5–10) (n = 45) | Rd ≤ 5 (n = 28) | P Value | |
|---|---|---|---|---|
| Age, yr | 50 ± 2 | 50 ± 2 | 53 ± 2 | 0.49 |
| Sex (male), % | 52 | 67 | 86† | 0.04 |
| Body mass index, kg/m2 | 28.3 ± 0.8 | 31.2 ± 0.3* | 31.7 ± 0.4† | <0.0001 |
| Total body fat, % | 30 ± 2 | 31 ± 1 | 30 ± 1 | 0.86 |
| Type 2 diabetes mellitus, % | 33 | 38 | 61 | 0.09 |
| Hb A1c, % | 6.0 ± 0.2 | 5.9 ± 0.1 | 6.7 ± 0.2†# | 0.002 |
| Fasting plasma glucose, mg/dl | 104 ± 3 | 115 ± 4 | 122 ± 5† | 0.03 |
| Fasting plasma insulin, μU/ml | 5 ± 1 | 10 ± 1* | 18 ± 2†# | <0.0001 |
| Fasting FFA, mmol/l | 0.58 ± 0.05 | 0.55 ± 0.04 | 0.56 ± 0.04 | 0.93 |
| Liver fat, % | 15 ± 3 | 24 ± 2 | 28 ± 2† | 0.008 |
| AST, U/l | 32 ± 4 | 35 ± 3 | 51 ± 4†# | <0.001 |
| ALT, U/l | 38 ± 5 | 51 ± 4 | 76 ± 8†# | <0.001 |
| Measures of insulin sensitivity | ||||
| HOMA-IR | 1.2 ± 0.1 | 2.9 ± 0.3* | 5.2 ± 0.6†# | <0.0001 |
| Adipo-IR, mmol·l−1·μU−1·ml−1 | 1.9 ± 0.3 | 4.2 ± 0.5* | 7.5 ± 0.9†# | <0.0001 |
| HIRI, mg·kg−1·min−1 per μU/ml | 8.5 ± 0.6 | 15.5 ± 1.4 | 29.7 ± 3.4†# | <0.0001 |
| Muscle insulin sensitivity (Rd), mg·kg LBM−1·min−1 | 12.6 ± 0.5 | 7.0 ± 0.2* | 3.6 ± 0.2†# | <0.0001 |
| Suppression of EGP, % | 54 ± 4 | 41 ± 3 | 30 ± 4†# | <0.001 |
| Suppression of FFA, % | 70 ± 4 | 54 ± 2* | 35 ± 3†# | <0.0001 |
| Plasma BCAA | ||||
| Valine (basal) | 307 ± 19 | 343 ± 7 | 344 ± 8 | 0.056 |
| Valine (insulin stimulated) | 194 ± 12 | 240 ± 6* | 277 ± 8†# | <0.001 |
| Leucine (basal) | 174 ± 13 | 193 ± 5 | 193 ± 6 | 0.162 |
| Leucine (insulin stimulated) | 72 ± 6 | 102 ± 3* | 130 ± 5†# | <0.001 |
| Isoleucine (basal) | 137 ± 10 | 153 ± 4 | 157 ± 5 | 0.083 |
| Isoleucine (insulin stimulated) | 50 ± 4 | 75 ± 3* | 99 ± 4†# | <0.001 |
Values are represented as means ± SE.
AST, aspartate aminotransferase; ALT, alanine aminotransferase; HOMA-IR, homeostatic model assessment of insulin resistance; Adipo-IR, adipose tissue insulin resistance index; Rd, glucose disposal; EGP, endogenous glucose production; FFA, free fatty acids; HIRI, hepatic insulin resistance index; LBM, lean body mass; BCAA, branched-chain amino acids.
Pairwise comparisons were performed using Bonferroni's multiple-comparison tests.
*
P < 0.05 between Rd ≥ 10 and Rd (5–10);
†
P < 0.05 between Rd ≥ 10 and Rd ≤ 5;
#
P < 0.05 between Rd (5–10) and Rd ≤ 5.