Baron A D, Brechtel G
Department of Medicine, Indiana University Medical Center, Indianapolis, Indiana 46202.
Am J Physiol. 1993 Jul;265(1 Pt 1):E61-7. doi: 10.1152/ajpendo.1993.265.1.E61.
To explore the relationships among insulin action, vascular resistance, and insulin sensitivity, we studied three groups of lean (Ln) and one group of obese (Ob) men. Glucose uptake was measured in whole body (WBGU) and in leg muscle (LGU) under basal and hyperinsulinemic euglycemic conditions. Mean arterial pressure (MAP), cardiac output (CO), leg blood flow (LBF), and systemic (SVR) and leg (LVR) vascular resistance were also ascertained. Ln groups were studied during insulin infusion rates of 20, 40, and 600 mU.m-2.min-1 and the Ob group at 40 mU.m-2.min-1. In Ob vs. Ln groups, WBGU and LGU were reduced by 51 (P < 0.01) and 42% (P < 0.05), respectively. In response to insulin, LBF increased > 60% (P < 0.01) in Ln groups but only approximately 20% in the Ob group, P = not significant (NS). CO was unchanged in Ob compared with a 15% increase (P < 0.05) in Ln groups, LBF was highly correlated with CO, r 0.70, P < 0.001. During hyperinsulinemia, MAP and LVR decreased in Ln (P < 0.001) but not in the Ob group (P = NS). In Ln groups, SVR decreased by 26 vs. 9% in the Ob group, P < 0.01. In summary, 1) insulin decreases LVR more than SVR and via this mechanism redistributes CO to insulin-sensitive tissues, 2) this insulin effect is blunted in Ob humans, and 3) insulin decreases MAP and vascular resistance more effectively in insulin-sensitive than in insulin-resistant subjects. In conclusion, insulin resistance to carbohydrate metabolism is associated with resistance to insulin's effect to decrease skeletal muscle vascular resistance and as such could act as a risk factor for the development of hypertension.
为探究胰岛素作用、血管阻力和胰岛素敏感性之间的关系，我们研究了三组瘦（Ln）性男性和一组肥胖（Ob）男性。在基础和高胰岛素正常血糖条件下，测量了全身葡萄糖摄取量（WBGU）和腿部肌肉葡萄糖摄取量（LGU）。还测定了平均动脉压（MAP）、心输出量（CO）、腿部血流量（LBF）以及全身血管阻力（SVR）和腿部血管阻力（LVR）。Ln组在胰岛素输注速率为20、40和600 mU·m⁻²·min⁻¹时进行研究，Ob组在40 mU·m⁻²·min⁻¹时进行研究。与Ln组相比，Ob组的WBGU和LGU分别降低了51%（P < 0.01）和42%（P < 0.05）。对胰岛素的反应中，Ln组的LBF增加>60%（P < 0.01），而Ob组仅增加约20%，P =无显著性差异（NS）。与Ln组增加15%（P < 0.05）相比，Ob组的CO无变化，LBF与CO高度相关，r = 0.70，P < 0.001。在高胰岛素血症期间，Ln组的MAP和LVR降低（P < 0.001），而Ob组无变化（P = NS）。Ln组的SVR降低了26%，而Ob组降低了9%，P < 0.01。总之，1）胰岛素降低LVR的程度大于SVR，并通过这种机制将CO重新分配到胰岛素敏感组织；2）这种胰岛素效应在肥胖人群中减弱；3）胰岛素在胰岛素敏感受试者中比在胰岛素抵抗受试者中更有效地降低MAP和血管阻力。总之，对碳水化合物代谢的胰岛素抵抗与胰岛素降低骨骼肌血管阻力的作用抵抗相关，因此可能是高血压发生的危险因素。
