Remuzzi A, Viberti G, Ruggenenti P, Battaglia C, Pagni R, Remuzzi G
Mario Negri Institute for Pharmacological Research; Ospedali Riuniti di Bergamo, Italy.
Am J Physiol. 1990 Oct;259(4 Pt 2):F545-52. doi: 10.1152/ajprenal.1990.259.4.F545.
We have studied the effect of acute hyperglycemia on glomerular function in seven insulin-dependent diabetics with overt nephropathy during hyperglycemic or euglycemic clamp. In all patients glomerular filtration rate (GFR) was higher during hyperglycemia than during euglycemia (35.0 +/- 15.5 vs. 21.4 +/- 10.3 ml.min-1.1.73 m-2, P less than 0.01), whereas renal plasma flow did not change significantly. To establish which determinant of GFR is altered by hyperglycemia, fractional clearances of neutral dextrans of graded molecular size were determined in both glycemic states, and data were analyzed by a theoretical model of hindered transport of macromolecules through a porous membrane. Hyperglycemia significantly increased sieving coefficients of small dextran molecules (28-40 A in radius), whereas fractional clearances of large macromolecules (greater than 44 A) did not change. Theoretical analysis suggested that the ultrafiltration coefficient (Kf) and membrane permeability to small dextrans (less than 40 A) increased in hyperglycemia in respect to euglycemia. Because these results have been obtained in patients with severe renal failure and hypertension, our conclusions do not necessarily apply to the early phase of diabetic nephropathy.
我们研究了在高血糖或正常血糖钳夹期间，急性高血糖对7例显性肾病的胰岛素依赖型糖尿病患者肾小球功能的影响。在所有患者中，高血糖期间的肾小球滤过率（GFR）高于正常血糖期间（35.0±15.5对21.4±10.3 ml·min⁻¹·1.73 m⁻²，P＜0.01），而肾血浆流量无显著变化。为确定高血糖改变了GFR的哪个决定因素，在两种血糖状态下测定了不同分子大小的中性右旋糖酐的分数清除率，并通过大分子通过多孔膜的受阻转运理论模型分析数据。高血糖显著增加了小右旋糖酐分子（半径28 - 40 Å）的筛滤系数，而大分子量分子（大于44 Å）的分数清除率未改变。理论分析表明，与正常血糖相比，高血糖时超滤系数（Kf）和对小右旋糖酐（小于40 Å）的膜通透性增加。由于这些结果是在严重肾衰竭和高血压患者中获得的，我们的结论不一定适用于糖尿病肾病的早期阶段。
