Giacca A, Gupta R, Efendic S, Hall K, Skottner A, Lickley L, Vranic M
Department of Physiology, University of Toronto, Canada.
Diabetes. 1990 Mar;39(3):340-7. doi: 10.2337/diab.39.3.340.
The effects of equipotent glucose-lowering doses of insulinlike growth factor I (IGF-I) and insulin on tracer-determined glucose kinetics and several metabolites were compared in 14 experiments (7 in each group) in fasted, totally depancreatized dogs. This model prevented variations in insulin secretion induced by IGF-I and permitted evaluation of the effects of IGF-I on extrapancreatic glucagon. Steady-state moderate hyperglycemia (9.9 +/- 0.2 mM) was maintained by a subbasal intraportal infusion of insulin (1.29 +/- 0.17 pmol.kg-1.min-1). This was continued throughout the experiment, allowing evaluation of IGF-I effects on insulin clearance. Human recombinant IGF-I or insulin was given intravenously as a primed infusion for 90 min, followed by a 50-min recovery period. The dose of IGF-I was a 2.6-nmol/kg bolus plus 57.4 pmol.kg-1.min-1. The insulin dose required to induce the same plasma glucose decline as IGF-I (44 +/- 6 vs. 43 +/- 5%, NS) was 9-12 times lower (0.06-nmol/kg bolus + 6.4 +/- 0.6 pmol.kg-1.min-1). However, the mechanism of this decline differed with IGF-I and insulin; glucose production was much less suppressed (25 +/- 9 vs. 42 +/- 11%, P less than 0.001) and glucose utilization was more stimulated (68 +/- 18 vs. 38 +/- 19%, P less than 0.05) with IGF-I.(ABSTRACT TRUNCATED AT 250 WORDS)
在14项实验（每组7项）中，对禁食且完全胰腺切除的犬只，比较了等剂量降血糖的胰岛素样生长因子I（IGF-I）和胰岛素对示踪剂测定的葡萄糖动力学及几种代谢物的影响。该模型可防止IGF-I诱导的胰岛素分泌变化，并能评估IGF-I对胰腺外胰高血糖素的作用。通过门静脉内输注低于基础量的胰岛素（1.29±0.17 pmol·kg⁻¹·min⁻¹）维持稳态中度高血糖（9.9±0.2 mM）。整个实验过程中持续此操作，以评估IGF-I对胰岛素清除率的影响。人重组IGF-I或胰岛素以静脉内首剂输注90分钟，随后为50分钟的恢复期。IGF-I的剂量为2.6 nmol/kg推注加57.4 pmol·kg⁻¹·min⁻¹。诱导与IGF-I相同血浆葡萄糖下降所需的胰岛素剂量（44±6对43±5%，无显著性差异）低9至12倍（0.06 nmol/kg推注 + 6.4±0.6 pmol·kg⁻¹·min⁻¹）。然而，这种下降的机制在IGF-I和胰岛素之间有所不同；IGF-I使葡萄糖生成受抑制程度小得多（25±9对42±11%，P<0.001），而葡萄糖利用受刺激程度更大（68±18对38±19%，P<0.05）。（摘要截短于250字）
