Glomerular size and charge selectivity in the rat as revealed by FITC-ficoll and albumin

Am J Physiol Renal Physiol. 2000 Jul;279(1):F84-91. doi: 10.1152/ajprenal.2000.279.1.F84.


The fractional clearances (theta) for FITC-Ficoll and albumin were estimated in isolated perfused rat kidneys in which the tubular activity was inhibited by low temperature (8 degrees C) and/or 10 mM NH(4)Cl. The Ficoll data were analyzed according to a two-pore model giving small and large pore radii of 46 A and 80-87 A, respectively. The estimated negative charge density was 35-45 meq/l at 8 degrees C. Perfusion with erythrocyte-free solutions of kidneys at 37 degrees C reduced glomerular size and charge permselectivity. Thus the large pore fraction of the glomerular filtrate (f(L)) was 1.64% at 37 degrees C compared with 0.94% at 8 degrees C. The theta for albumin was four times higher at 37 degrees C than at 8 degrees C (0.86% vs. 0.19%, respectively). NH(4)Cl caused further irreversible damage to the glomerular barrier. We conclude that there are no deleterious effects on the glomerular barrier of a reduction in temperature from 37 degrees C to 8 degrees C. Therefore our data seem to disprove the hypothesis of low glomerular permselectivity and transtubular uptake of intact albumin and support the classic concept of a highly selective glomerular barrier.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ammonium Chloride / pharmacology
  • Animals
  • Biological Transport / drug effects
  • Calibration
  • Diffusion
  • Ficoll / analogs & derivatives*
  • Ficoll / chemistry
  • Ficoll / metabolism
  • Fluorescein-5-isothiocyanate / analogs & derivatives*
  • Fluorescein-5-isothiocyanate / chemistry
  • Fluorescein-5-isothiocyanate / metabolism
  • Glomerular Filtration Rate
  • In Vitro Techniques
  • Kidney Glomerulus / blood supply
  • Kidney Glomerulus / drug effects
  • Kidney Glomerulus / metabolism*
  • Kidney Glomerulus / physiology
  • Male
  • Models, Biological*
  • Perfusion
  • Rats
  • Rats, Wistar
  • Serum Albumin / chemistry
  • Serum Albumin / metabolism*
  • Substrate Specificity
  • Temperature
  • Time Factors


  • Serum Albumin
  • fluorescein 5-isothiocyanate-Ficoll
  • Ammonium Chloride
  • Ficoll
  • Fluorescein-5-isothiocyanate