An Evaluation of Possible Sites of Phosphate Secretion in the Rat Nephron

  • Franklyn G. Knox
  • John Haas
  • Theresa Berndt
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 103)


Although net secretion of phosphate has been demonstrated in non-mammalian species, the secretion of phosphate in mammals has been difficult to demonstrate using clearance methods (1). In these studies, plasma phosphate was elevated by infusion of phosphate and the clearance of phosphate was compared to the clearance of a glomerular marker (usually inulin). The results were equivocal with some investigators reporting net secretion, while others did not. In recent studies by Boudry et al (2), phosphate clearances were greater than inulin clearances in conscious rats when plasma Pi concentration was corrected for ultrafilterability. Likewise, in studies by Troehler et al (3), rats fed a high phosphate diet for 10 days and then infused acutely with phosphate, had a FEp% of 97% without correction for plasma ultrafilterability. Since it is highly unlikely that unidirectional outflux of phosphate (reabsorption) was abolished completely in these studies, this data has been taken as evidence for a secretory component of net phosphate transport if not net secretion per se.


Proximal Tubule Phosphate Transport Secretory Component Phosphate Reabsorption Single Nephron Glomerular Filtration Rate 
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  1. 1.
    Knox, F.G., Schneider, E.G., Willis, L.R., Strandhoy, J.W., and Ott, C.E.: Site and control of phosphate reabsorption by the kidney. Kidney Int. 3: 347–353, 1973.PubMedCrossRefGoogle Scholar
  2. 2.
    Boudry, J.F., Troehler, U., Toubai, M., Fleisch, H., and Bonjour, J.P.: Secretion of inorganic phosphate in the rat nephron. Clin. Sci. Mol. Med. 48: 475–489, 1975.Google Scholar
  3. 3.
    Troehler, U., Bonjour, J.P., and Fleisch, H.: Inorganic phosphate homeostasis. Renal adaptation to the dietary intake in intact and thyroparathyroidectomized rats. J. Clin. Invest. 57: 264–273, 1976.CrossRefGoogle Scholar
  4. 4.
    Murayama, Y., Morel, F., and LeGrimellec, C.: Phosphate, calcium and magnesium transfers in proximal tubules and loops of Henle, as measured by single nephron microperfusion experiments in the rat. Pflugers Archiv. 333: 1–16, 1972.PubMedCrossRefGoogle Scholar
  5. 5.
    Greger, R.F., Lang, F.C., Knox, F.G., and Lechene, C.P.: Absence of significant secretory flux of phosphate in the proximal convoluted tubule. Am. J. Physiol. 232: F235–238, 1977.PubMedGoogle Scholar
  6. 6.
    Shirley, D.G., Poujeol, P., and LeGrimellec, C.: Phosphate, calcium and magnesium fluxes into the lumen of the rat proximal convoluted tubule. Pflugers Archiv. 362: 247–254, 1976.PubMedCrossRefGoogle Scholar
  7. 7.
    Dennis, V.W., Woodhall, P.B., and Robinson, R.R.: Characteristics of phosphate transport in isolated proximal tubule. Am. J. Physiol. 231: 979–983, 1976.PubMedGoogle Scholar
  8. 8.
    Schneider, E.G., and McLane, L.A.: Evidence for a peritubularto luminal flux of phosphate in the dog kidney. Am. J. Physiol. 1: 159–166, 1977.Google Scholar
  9. 9.
    Knox, F.G., Haas, J.A., Berndt, T., Marchand, G.R., Youngberg, S.P.: Phosphate transport in superficial and deep nephrons in phosphate loaded rats. Am. J. Physiol., in press, 1977.Google Scholar
  10. 10.
    Lang, F.C., Greger, R.F., Marchand, G.R., and Knox, F.G.: Stationary microperfusion study of phosphate reabsorption in proximal and distal nephron segments. Pflugers Archiv., in press, 1977.Google Scholar
  11. 11.
    Haas, J.A., Larson, M., Marchand, G.R., Lang, F., Greger, R., and Knox, F.G.: Phosphaturic effect of furosemide, role of PTH and carbonic anhydrase. Am. J. Physiol. 1: F105–110, 1977.Google Scholar
  12. 12.
    Rocha, A.S., and Magaldi, J.B.: Calcium and phosphate transport in isolated segments of Henle’s loop. J. Clin. Invest. 59: 975–984, 1977.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1978

Authors and Affiliations

  • Franklyn G. Knox
    • 1
  • John Haas
    • 1
  • Theresa Berndt
    • 1
  1. 1.Nephrology Research Laboratory, Departments of Physiology & Biophysics and MedicineMayo Clinic & Mayo FoundationRochesterUSA

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