TRANSPORT OF OXALATE ACROSS THE RABBIT PAPILLARY SURFACE EPITHELIUM

Purpose: The renal papilla and pelvic recesses of the mammalian kidney are thought to be the anatomical sites of initial kidney stone formation. We studied oxalate transport across the renal papillary surface epithelium.Materials and Methods: In vitro oxalate transport across the papillary surface epithelium was studied by dissecting it off of the papilla and mounting it in a modified Ussing chamber. Experiments were conducted using physiological Ringer’s solution at 37C. Removal or appearance of radioactive oxalate from the solution bathing the apical papillary surface epithelium surface was used as a measure of transepithelial transport.Results: When only the papillary surface epithelium apical surface was exposed to oxalate (17 μmol./l.), the apical to basolateral flux of oxalate was 7.1 ± 1.5 nmol./cm.2 per hour. When only the basolateral side was perfused with oxalate, the basolateral to apical oxalate flux was 1.6 ± 0.7 nmol./cm.2 per hour. When the apical and basolateral surfaces were exposed to ox...