ABSTRACT
Ischemia .........................................................................................541 25.4 Summary ......................................................................................................545 Acknowledgments..................................................................................................546 References..............................................................................................................546
The primary functions of the kidney, maintaining body volume and electrolyte balance, while removing nitrogenous and other waste products from the blood, are dependent upon size-selective filtration across the glomerulus and specific reabsorption of water, ions, and macromolecules by tubular epithelial cells. Regulation of these interrelated processes at the cellular level requires structural and biochemical polarization of the surface membrane of participating epithelial cells. For example, with normal renal function, approximately 150 liters of glomerular filtrate are produced every 24 h. About 99% of this volume is reabsorbed, and between 70 and 80% of this reabsorption occurs across proximal tubule cells. Therefore, small
