TABLE 2

Tracer-determined HGU and HGR, net hepatic CO2 production, and arterial blood concentrations of substrates and ketones in 42-h-fasted conscious dogs receiving intraportal insulin and glucagon infusions at basal rates, intraportal glucose infusion, and peripheral infusions of NA, NAG, or NAL

Parameter and groupStudy period
BasalPeriod 1Period 2
HGU (μmol · kg−1 · min−1)
 NA0.0 ± 1.19.8 ± 1.89.7 ± 1.3
 NAG0.8 ± 0.78.9 ± 4.211.3 ± 6.6
 NAL1.0 ± 1.28.4 ± 1.27.1 ± 1.5
HGR (μmol · kg−1 · min−1)
 NA9.5 ± 1.52.0 ± 2.1−0.8 ± 2.2
 NAG8.3 ± 2.70.9 ± 1.7−1.6 ± 4.7
 NAL11.0 ± 1.01.6 ± 2.02.7 ± 2.1
Net hepatic CO2 production (μmol glucose equivalents · kg−1 · min−1)
 NA0.3 ± 0.20.7 ± 0.21.0 ± 0.2
 NAG0.4 ± 0.40.7 ± 1.90.8 ± 2.4
 NAL0.2 ± 0.11.0 ± 0.10.5 ± 0.1*
Arterial blood glycerol (μmol/l)
 NA89 ± 828 ± 224 ± 4
 NAG100 ± 2027 ± 4163 ± 17*
 NAL93 ± 934 ± 3196 ± 11*
Net hepatic glycerol uptake (μmol · kg−1 · min−1)
 NA2.0 ± 0.40.2 ± 0.10.2 ± 0.1
 NAG2.8 ± 0.90.4 ± 0.12.9 ± 0.1*
 NAL1.9 ± 0.30.3 ± 0.03.6 ± 0.2*
Arterial blood alanine (μmol/l)
 NA306 ± 34491 ± 32470 ± 45
 NAG229 ± 34348 ± 38335 ± 50
 NAL287 ± 18402 ± 32353 ± 33*
Net hepatic alanine uptake (μmol · kg−1 · min−1)
 NA3.2 ± 0.72.8 ± 0.33.2 ± 0.3
 NAG2.0 ± 0.52.1 ± 0.62.2 ± 0.2
 NAL3.0 ± 0.32.7 ± 0.23.1 ± 0.2
Arterial blood acetoacetate (μmol/l)
 NA83 ± 1473 ± 784 ± 19
 NAG128 ± 27113 ± 25141 ± 30
 NAL97 ± 1585 ± 1499 ± 15
Net hepatic acetoacetate output (μmol · kg−1 · min−1)
 NA0.8 ± 0.60.2 ± 0.10.1 ± 0.3
 NAG2.2 ± 1.00.5 ± 0.60.4 ± 0.2
 NAL1.4 ± 0.50.3 ± 0.10.4 ± 0.2
Arterial blood βOHB (μmol/l)
 NA38 ± 128 ± 15 ± 1
 NAG43 ± 1716 ± 2*13 ± 1*
 NAL39 ± 712 ± 318 ± 4*
Net hepatic βOHB output (μmol · kg−1 · min−1)
 NA1.8 ± 0.60.2 ± 0.10.1 ± 0.0
 NAG1.3 ± 0.60.2 ± 0.00.1 ± 0.0
 NAL1.5 ± 0.30.2 ± 0.00.4 ± 0.0*†

  • Data are means ± SE of two sampling points during the basal period and five sampling points during periods 1 and 2 (n = 7, 3, and 8 for NA, NAG, and NAL, respectively).

  • *

    * P < 0.05 vs. NA;

  • †

    † P < 0.05 vs. NAG.