PERMSELECTIVITY OF GLOMERULAR CAPILLARY WALL TO MACROMOLECULES .1. THEORETICAL CONSIDERATIONS
PERMSELECTIVITY OF GLOMERULAR CAPILLARY WALL TO MACROMOLECULES .1. THEORETICAL CONSIDERATIONS
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DOI：
10.1016/s0006-3495(75)85862-0
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发表时间：
1975-01-01
影响因子：
3.4
通讯作者：
BRENNER, BM
中科院分区：
文献类型：
--
作者：
CHANG, RLS;ROBERTSON, CR;BRENNER, BM
大分子通过肾小球毛细血管壁的转运已在理论上使用基于（a）通过小孔的限制性转运和（B）Kedem-Katchalsky公式的通量方程进行了描述。在这两种方法中固有的各种假设和限制进行了讨论。为了研究大分子溶质转运和肾小球滤过率的决定因素之间的耦合，这些通量方程与质量平衡关系相结合，允许跨膜驱动力沿着肾小球毛细血管的变化。据预测，使用孔理论和Kedem-Katchalsky方程，分数溶质清除率应强烈依赖于肾小球滤过率的决定因素时，对流和扩散都有助于溶质运输。然而，当对流成为跨毛细血管溶质转运的唯一机制时，溶质清除率分数基本上与肾小球滤过率决定因素的变化无关。因此，除非不存在扩散，否则单独的溶质清除分数不足以表征肾小球毛细血管壁的选择性渗透性质，因为这些值可能会因肾小球压力和流量的变化以及毛细血管壁本身性质的变化而改变。
The transport of macromolecules across the renal glomerular capillary wall has been described theoretically using flux equations based on (a) restricted transport through small pores, and (b) the Kedem-Katchalsky formulation. The various assumptions and limitations inherent in these two approaches are discussed. To examine the coupling between macromolecular solute transport and the determinants of glomerular filtration rate, these flux equations were combined with mass balance relations which allow for variations in the transmembrane driving forces along a glomerular capillary. It was predicted, using both pore theory and the Kedem-Katchalsky equations, that fractional solute clearance should be strongly dependent on the determinants of glomerular filtration rate when convection and diffusion both contribute to solute transport. When convection becomes the sole mechanism for transcapillary solute transport, however, fractional solute clearance is essentially independent of changes in the determinants of glomerular filtration rate. Consequently, unless diffusion is absent, fractional solute clearances alone are insufficient to characterize the permselective properties of the glomerular capillary wall, since these values may be altered by changes in glomerular pressures and flows as well as changes in the properties of the capillary wall per se.