Contribution of leaked load to solute transport by renal tubules

Academic Article

Abstract

  • Renal tubules reabsorb solutes from the glomerular filtrate. The relationship between 'filtered load' and reabsorption has been previously discussed and analyzed in detail. One aspect which has not been emphasized, however, is that, when reabsorption of a solute causes its concentration (or activity) in the tubule lumen to decrease below the level in the blood, solute may enter the tubule down this concentration gradient adding a 'leaked load' to the filtered load. The leaked load should be taken into account when quantifying tubular transport. In the present study we derived equations forestimating the leaked load and its contribution to transport. The importance of the leaked load of glucose in the rabbit proximal convoluted tubules is evaluated with parameters derived from in vitro perfusion and by solving the equations numerically. It is shown that, depending on the conditions, the leaked load of glucose may account for a substantial part of the glucose present in the tubule lumen and reabsorbed from the tubule. Also, the leaked load could concievably be an important factor in the transport of other solutes such as lactate and bicarbonate in proximal tubules.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Warnock DG; Patlak CS; Burg MB
  • Volume

  • 3
  • Issue

  • 6