Table 2

Measures of β-cell secretory capacity, β-cell sensitivity to glucose, insulin sensitivity, and glucagon secretion derived from the GPA test

Exenatide (n = 14)Sitagliptin (n = 12)Glimepiride (n = 14)
Baseline6 monthsaΔBaseline6 monthsaΔBaseline6 monthsaΔ
AIRarg (μU/mL)52 ± 1452 ± 11−0.2 ± 935 ± 434 ± 6−2 ± 744 ± 642 ± 4−2 ± 7
AIRpot (μU/mL)138 ± 31108 ± 21−30 ± 2083 ± 1280 ± 15−2 ± 897 ± 16119 ± 1922 ± 12
AIRmax (μU/mL)214 ± 60188 ± 34−25 ± 50149 ± 20158 ± 309 ± 21133 ± 19202 ± 35*69 ± 33
PG50 (mg/dL)175 ± 13190 ± 1425 ± 20226 ± 12209 ± 16−5 ± 24168 ± 17182 ± 1010 ± 26
M (mg · kg−1 · min−1)5.5 ± 0.35.8 ± 0.40.27 ± 0.45.4 ± 0.45.3 ± 0.4−0.1 ± 0.45.5 ± 0.45.8 ± 0.40.35 ± 0.4
I (μU/mL)41 ± 1339 ± 9−2 ± 922 ± 223 ± 41 ± 328 ± 726 ± 2−2 ± 5
M/I (mg · kg−1 · min−1/μU/mL)0.3 ± 0.10.3 ± 0.1−0.01 ± 0.00.3 ± 0.00.3 ± 0.10.04 ± 0.10.3 ± 0.10.3 ± 0.1−0.04 ± 0.0
AGRarg (pg/mL)60 ± 1263 ± 83 ± 1777 ± 1360 ± 11−17 ± 640 ± 962 ± 822 ± 17
AGRinh (pg/mL)63 ± 1258 ± 13−3 ± 664 ± 1355 ± 16−10 ± 1046 ± 759 ± 711 ± 7
AGRmin (pg/mL)51 ± 1252 ± 122 ± 555 ± 859 ± 194 ± 2137 ± 659 ± 8*21 ± 8
  • Data are means ± SE.

  • Δ, change from baseline to 6 months with each value.

  • aFinal visits after 6 months of therapy were conducted following a 5- to 7-day drug washout.

  • *P < 0.05 when comparing values within each group.

  • P < 0.05 when comparing Δ between the exenatide and glimepiride groups.

  • P ≤ 0.1 (statistical trend) when comparing Δ between exenatide and glimepiride groups.