Homeostatic efficiency of tubuloglomerular feedback is reduced in established diabetes mellitus in rats.
Homeostatic efficiency of tubuloglomerular feedback is reduced in established diabetes mellitus in rats.
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在患有糖尿病的大鼠中，肾小球反馈的稳态效率降低。
DOI：
10.1152/ajprenal.1995.269.6.f876
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Thomson,S
中科院分区：
文献类型：
--
作者：
Vallon,V;Blantz,RC;Thomson,S
我们验证了在7-8周胰岛素治疗链脲霉素糖尿病大鼠中，小管肾小球反馈（TGF）稳定肾功能的能力受损的假设。使用无创光学技术测量自由流动肾单位的近端管状流量。TGF的稳态效率是通过对环境流扰动的分数补偿来确定的。糖尿病大鼠的部分代偿显著降低。为了评估近端小管和亨氏环作为TGF效率决定因素的作用，我们通过标准微穿刺测试了糖尿病对近端小管重吸收的影响，并通过使用微电极在线测量电导率（TED）测试了糖尿病对早期远端小管液体离子含量的影响。糖尿病引起肾小球高滤过和部分近端小管重吸收（FPR）增加，因此晚期近端小管流动（VLP）和早期远端小管流动不受影响。FPR的增加对分数薪酬的总体影响是次要的。糖尿病降低了环境TED，但不影响VLP与TED之间关系的斜率。这些结果表明，TGF系统的稳态效率在糖尿病中降低，这不能完全用小管重吸收的变化来解释。TGF效率受损使糖尿病肾小球微血管更容易受到全身血流动力学波动的影响。
We tested the hypothesis that the ability of the tubuloglomerular feedback (TGF) to stabilize renal function is impaired in rats with 7-8 wk of insulin-treated streptozotocin-diabetes. Proximal tubular flow was measured in free-flowing nephrons using a noninvasive optical technique. The homeostatic efficiency of TGF was determined from the fractional compensation for perturbations in ambient flow. Fractional compensation was substantially reduced in diabetic rats. To assess the roles of the proximal tubule and loop of Henle as determinants of TGF efficiency, we tested the effect of diabetes on proximal tubular reabsorption as determined by standard micropuncture and on the ionic content of early distal tubular fluid by employing a microelectrode for on-line measurement of electrical conductivity (TED). Diabetes caused glomerular hyperfiltration and increased fractional proximal tubular reabsorption (FPR), such that late proximal tubular flow (VLP) and early distal tubular flow were unaffected. The increase in FPR was a minor contributor to the overall effect on fractional compensation. Diabetes decreased the ambient TED without affecting the slope of the relationship between VLP and TED. These results demonstrate that the homeostatic, efficiency of the TGF system is reduced in diabetes and that this cannot be fully accounted for by changes in tubular reabsorption. Impaired TGF efficiency renders the diabetic glomerular microvasculature more susceptible to impact from fluctuations in systemic hemodynamics.