van Veen S, Frölich M, Chang P C
Department of Nephrology, Leiden University Medical Center, The Netherlands.
J Hum Hypertens. 1999 Apr;13(4):263-8. doi: 10.1038/sj.jhh.1000774.
To evaluate whether acute elevations of local plasma glucose concentrations could influence forearm blood flow (FBF) and how this interacts with local hyperinsulinaemia in healthy volunteers.
Using the perfused forearm technique, in random order, glucose 20% or saline 0.9% as a control was infused in three dose steps (0.3, 1.0, and 3.0 ml/min) for 5 min each in eight healthy men. The infusion experiments were repeated, in random order, during local hyperinsulinaemia by intra-arterial infusion of insulin 0.05 mU/kg/min. The ratio of FBF of the infused over the FBF in the control arm (FR) was measured at 15-sec intervals during the infusions.
Glucose infusion increased the FR dose-dependently by 172%+/-39% (M+/-SE) at the highest dose (P < 0.01). During hyperinsulinaemia the glucose-induced increase in FR was significantly (P < 0.01) less, 96%+/-26%, however, when changes in FR or forearm vascular resistance were related to the plasma glucose concentrations both glucose infusions were equipotent. The saline infusions induced small increases in FR of 27+/-5% (P < 0.01) and 24+/-11% (P > 0.05), without or with insulin respectively. The changes in FR during the saline infusions were much smaller than during the glucose infusions (P < 0.01). During the glucose infusions small but significant increases in FBF and venous plasma glucose in the non-infused forearm appeared, indicating carry-over effect and the possibility of a very low threshold for glucose-induced vascular effects.
High, local levels of glucose in the forearm have a vasodilator effect on resistance vessels in skeletal muscle of the forearm that is not modified by local hyperinsulinaemia. Indications were found that the threshold for this glucose-induced vasodilation may be remarkably low, but this needs to be studied more formally.
评估局部血浆葡萄糖浓度的急性升高是否会影响前臂血流量（FBF），以及这在健康志愿者中如何与局部高胰岛素血症相互作用。
采用前臂灌注技术，对8名健康男性按随机顺序，以三个剂量步骤（0.3、1.0和3.0毫升/分钟）分别输注20%葡萄糖或0.9%生理盐水作为对照，每次输注5分钟。在局部高胰岛素血症期间，通过动脉内输注0.05 毫单位/千克/分钟的胰岛素，按随机顺序重复进行输注实验。在输注过程中，每隔15秒测量一次输注侧前臂血流量与对照侧前臂血流量的比值（FR）。
葡萄糖输注使FR在最高剂量时剂量依赖性增加172%±39%（均值±标准误）（P<0.01）。在高胰岛素血症期间，葡萄糖诱导的FR增加显著减少（P<0.01），为96%±26%，然而，当FR或前臂血管阻力的变化与血浆葡萄糖浓度相关时，两种葡萄糖输注的效果相当。生理盐水输注分别使FR小幅增加27±5%（P<0.01）和24±11%（P>0.05），分别在无胰岛素和有胰岛素的情况下。生理盐水输注期间FR的变化远小于葡萄糖输注期间（P<0.01）。在葡萄糖输注期间，未输注侧前臂的FBF和静脉血浆葡萄糖出现小幅但显著的增加，表明存在残留效应以及葡萄糖诱导血管效应的阈值可能非常低。
前臂局部高血糖水平对前臂骨骼肌阻力血管有血管舒张作用，且不受局部高胰岛素血症的影响。有迹象表明，这种葡萄糖诱导的血管舒张阈值可能非常低，但这需要更正式的研究。
