Pître M, Nadeau A, Bachelard H
Hypertension Research and Diabetes Research Unit, Centre Hospitalier de l'Université Laval Research Center, Laval University, Ste-Foy, Quebec, Canada.
Am J Physiol. 1996 Oct;271(4 Pt 1):E658-68. doi: 10.1152/ajpendo.1996.271.4.E658.
The insulin-mediated vasodilator effect has been proposed as an important physiological determinant of insulin action on glucose disposal in normotensive humans. The present study was designed to further examine the acute regional hemodynamic effects of insulin in different vascular beds and to explore the relationships between insulin vascular effects and insulin sensitivity during euglycemic hyperinsulinemic clamps in conscious normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The rats were instrumented with intravascular catheters and pulsed Doppler flow probes to measure blood pressure, heart rate, and regional blood flows. In WKY rats, the euglycemic infusion of insulin (4 and 16 mU.kg-1.min-1) causes vasodilations in renal and hindquarter vascular beds but no changes in mean blood pressure, heart rate, or superior mesenteric vascular conductance. In contrast, in SHR, the same doses of insulin produce vasoconstrictions in superior mesenteric and hindquarter vascular beds and, at high doses, increase blood pressure. Moreover, at the lower dose of insulin tested, we found a reduction in the insulin sensitivity index in the SHR compared with the WKY rats. The present findings provide further evidence for an association between insulin sensitivity and insulin-mediated hemodynamic responses.
胰岛素介导的血管舒张作用被认为是血压正常的人体中胰岛素对葡萄糖代谢作用的重要生理决定因素。本研究旨在进一步研究胰岛素在不同血管床中的急性区域血流动力学效应，并探讨在清醒的血压正常的Wistar-Kyoto（WKY）大鼠和自发性高血压大鼠（SHR）进行正常血糖高胰岛素钳夹试验期间，胰岛素血管效应与胰岛素敏感性之间的关系。给大鼠植入血管内导管和脉冲多普勒血流探头，以测量血压、心率和区域血流量。在WKY大鼠中，正常血糖状态下输注胰岛素（4和16 mU·kg-1·min-1）可使肾血管床和后肢血管床舒张，但平均血压、心率或肠系膜上血管传导率无变化。相比之下，在SHR中，相同剂量的胰岛素可使肠系膜上血管床和后肢血管床收缩，高剂量时可升高血压。此外，在测试的较低胰岛素剂量下，我们发现SHR的胰岛素敏感性指数低于WKY大鼠。本研究结果为胰岛素敏感性与胰岛素介导的血流动力学反应之间的关联提供了进一步的证据。
