Characteristics of phosphate transport in isolated proximal tubule
- 1 September 1976
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Legacy Content
- Vol. 231 (3), 979-985
- https://doi.org/10.1152/ajplegacy.1976.231.3.979
Abstract
The characteristics of inorganic phosphate transport in isolated perfused proximal tubules of the rabbit were examined using radioisotopic techniques. When tubules were perfused with an ultrafiltrate of rabbit serum, the mean lumen-to-bath flux of phosphate in the convoluted segment was 6.60 +/- 1.41 (SE) pmol/mm-min with a simultaneous back-to-lumen flux of 0.45 +/- 0.08. In the straight portion of the proximal tubule, the lumen-to-bath flux was significantly lower (P less than 0.01) at 2.22 +/- 0.48 pmol/min-min with a bath-to-lumen flux of 0.31 +/- 0.05. The lumen-to-bath flux was not affected by increases in the intraluminal phosphate concentration from 2.00 +/- 0.19 to 3.12 +/- 0.34 mM or by the isohydric replacement of bicarbonate in the ambient fluids with chloride. However, phosphate absorption was completely inhibited by ouabain 10(-5) M in the bath. These data indicate that phosphate absorption in these segments occurs by a mechanism other than independent diffusion and is saturated at phosphate concentrations characteristic of normal glomerular filtrate. There is no evidence for significant phosphate transport from bath to lumen.This publication has 2 references indexed in Scilit:
- Micropuncture Studies of Phosphate Transport in the Proximal Tubule of the Dog THE RELATIONSHIP TO SODIUM REABSORPTIONJCI Insight, 1974
- Effect of vasopressin and cyclic AMP on permeability of isolated collecting tubulesAmerican Journal of Physiology-Legacy Content, 1966