The Journal of Membrane Biology

, Volume 26, Issue 1, pp 91–107 | Cite as

Amide transport channels across toad urinary bladder

  • Sherman D. Levine
  • Ronald E. Worthington


Urea and other small amides cross the toad urinary bladder by a vasopressinsensitive pathway which is independent of somotic water flow. Amide transport has characteristics of facilitated transport: saturation, mutual inhibition between amides, and selective depression by agents such as phloretin. The present studies were designed to distinguish among several types of transport including (1) movement thought a fixed selective membrane channel and (2) movement via a mobile carrier. The former wold be characterized by co-transport (acceleration of labele amide flow in the direction of net flow in the opposite direction). Mucosal to serosal (M→S) and serosal to mucosal (S→M) permeabilities of labeled amides were determined in paired bladers. Unlabeled methylurea, a particularly potent inhibitor of amide movement, was added to either the M or S bath, while osmotic water flow was eliminated by addition of ethylene glycol to the opposite bat. Co-transport of labeled methylurea and, to a lesser degree, acetamide and urea with unlabeled methylurea was observed. Co-transport of the nonamides ethylene glycol and ethanol could not be demonstrated. Methylurea did not alter water permeability or transmembrane electrical resistance. The demonstration of co-transport is consistent with the presence of ADH-sensitive amide-selective channcels rather than a mobile carrier.


Amide Water Flow Acetamide Water Permeability Mobile Carrier 
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  1. 1.
    Andersen, B., Using, H.H. 1957. Solventdrag on non-electrolytes during osmotic flow through isolated toad skin and its response to antidiuretic hormone.Acta Physiol. Scand. 39:228PubMedGoogle Scholar
  2. 2.
    Bentley, P.J. 1958. The effects of neurohypophyseal extracts on water transfer across the wall of the isolated urinary bladder of the toadBufo marinus.J. Endorcrinol. 17:201Google Scholar
  3. 3.
    Biber, T.U.L., Curran, P.E., 1968. Coupled solute fluxes in toad skin.J. Gen. Physiol. 51:606PubMedGoogle Scholar
  4. 4.
    DiBona, D.R. 1972. Passive intercellular pathways in amphibian epithelia.Nature, New Biol. 238:179Google Scholar
  5. 5.
    DiBona, D.R., Civan, M.M. 1973. Pathways for movement of ions and water across toad urinary bladder.J. Membr. Biol. 12:101PubMedGoogle Scholar
  6. 6.
    Eggena, P. 1973. Inhibition of vasorpressin-stimulated urea transport across the toad blader by thiourea.J. Clin. Invest. 52:2963PubMedGoogle Scholar
  7. 7.
    Franz, T.J., Van Bruggen, J.T. 1967. Hyperosmolality and the net transport of nonelectrolytes in frog skin.J. Gen. Physiol. 50:933PubMedGoogle Scholar
  8. 8.
    Galey, W.R., Van Bruggen, J.T. 1970. The coupling of solute fluxes in membranes.J. Gen. Physiol. 55:220PubMedGoogle Scholar
  9. 9.
    Heckman, K. 1972. Single file difusion.In: Pasive Permeability of Cell Membranes. F. Kreuzer and J.F.G. Slegers, editors. p. 127, Plenum Press, New YorkGoogle Scholar
  10. 10.
    Hodgkin, A.L., Keynes, R.D. 1955. The potassium permeability of a giant nerve fiber.J. Physiol. 128:61Google Scholar
  11. 11.
    Kokko, J.P., Rector, F.C., Jr. 1972. Countercurrent multiplication system without active transport in inner medulla.Kidney Int. 2:214PubMedGoogle Scholar
  12. 12.
    Leaf, A., Hays, R.M. 1962. Permeability of the isolated toad bladder to solutes and its modification by vasorpressin.J. Gen. Physiol. 45:921PubMedGoogle Scholar
  13. 13.
    Levine, S., Franki, N., Hays, R.M. 1973. Effect of phloretin on water and solute movement in the toad bladder.J. Clin. Invest. 52:1435PubMedGoogle Scholar
  14. 14.
    Levine, S., Franki, N., Hays, R.M. 1973. A saturable vasopressin-sensitive carrier for urea and acetamide in the toad bladder epithelial cell.J. Clin. Invest. 52:2083PubMedGoogle Scholar
  15. 15.
    Levine, S.D., Levine, R.D., Worthington, R.E., Hays, R.M. 1975. Selective inhibition of osmotic water flow by methoxyflurane and halothane.Clin. Res. 23:432AGoogle Scholar
  16. 16.
    Levine, S.D., Levine, R.D., Worthington, R.E., Hays, R.M. 1975. Selective inhibition of osmotic water flow in toad urinary bladder by general anesthetics.Proc V. Int. Biophys. Cong. p. 68Google Scholar
  17. 17.
    Li, J.H., DeSousa, R.C., Essig, A. 1974. Kinetics of tracer flows and isotope interaction in an ion exchange membrane.J. Membr. Biol. 19:93PubMedGoogle Scholar
  18. 18.
    Lief, P.D., Essig, A. 1973. Urea transport in the toad bladder; coupling of urea flows.J. Membr. Biol. 12:159PubMedGoogle Scholar
  19. 19.
    Macey, R.I., Farmer, R.E.L. 1970. Inhibition of water and solute movement in human red cells.Biochim. Biophys. Acta 211:104PubMedGoogle Scholar
  20. 20.
    Maffly, R.H., Hays, R.M., Lamdin, E., Leaf, A. 1960. The effect of neurohypophyseal hormones on the permeability of the toad bladder to urea.J. Clin. Invest. 39:630PubMedGoogle Scholar
  21. 21.
    Mandel, L.J. 1975. Actions of external hypertonic urea, ADH, and theophylline on transcellular and extracellular solute permeabilities in frog skin.J. Gen. Physiol. 65:599PubMedGoogle Scholar
  22. 22.
    Patlak, C.S. 1957. Contributions to the theory of active transport.Bull. Math. Biophys. 19:209Google Scholar
  23. 23.
    Rubin, M.S. 1975. Chemical modification of vasopressin (ADH)-induced urea transport across toad bladder.Fed. Proc. 34:327Google Scholar
  24. 24.
    Schmidt-Nielsen, B. 1970. Urea analogues and tubular transport competition.In: Urea and the Kidney. B. Schmidt-Nielsen, editor. p. 252. Excerpta Medica Foundation, AmsterdamGoogle Scholar
  25. 25.
    Shuchter, S.H., Franki, N., Hays, R.M. 1973. The effect of tanning agents on the permeability of the toad bladder to water and solutes.J. Membr. Biol. 14:177PubMedGoogle Scholar
  26. 26.
    Snedecor, G.W., Cochran, W.G. 1967. Statistical Methods (6th ed). p. 91. Iowa State University Press, Ames, IowaGoogle Scholar
  27. 27.
    Stewart, J., Luggen, M.E., Valtin, H. 1972. A computer model of the renal countercurrent system.Kidney Int. 2:253PubMedGoogle Scholar
  28. 28.
    Urakabe, S., Handler, J.S., Orloff, J. 1970. Effect of hypertonicity on permeability properties of the toad bladder.Am. J. Physiol. 218:1179PubMedGoogle Scholar
  29. 29.
    Ussing, H.H. 1966. Anomalous transport of electrolytes and sucrose through the isolated frog skin induced by hypertonicity of the outside bathing solution.Ann. N.Y. Acad. Sci. 137:543PubMedGoogle Scholar
  30. 30.
    Ussing, H.H., Windhager, E.E. 1964. Nature of shunt path and active sodium transport path through frog skin epithelium.Acta Physiol. Scand. 61:484PubMedGoogle Scholar
  31. 31.
    Van Bruggen, J.T., Boyett, J.D., van Bueren, A.L., Galey, W.R. 1974. Solute flux coupling in a homopore membrane.J. Gen. Physiol. 63:639PubMedGoogle Scholar
  32. 32.
    Vidaver, G.A. 1966. Inhibition of parallel flux and augmentation of counter flux shown by transport models not involving a mobile carrier.J. Theoret. Biol. 10:301Google Scholar
  33. 33.
    Wade, J.B., Revel, J.-P., DiScala, V.A. 1973. Effect of osmotic gradients on intercellular junctions of the toad bladder.Am. J. Physiol. 224:407PubMedGoogle Scholar
  34. 34.
    Widdas, W.F. 1952. Inability of diffusion to account for placental glucose transfer in the sheep and consideration of the kinetics of a possible carrier transfer.J. Physiol. 118:23PubMedGoogle Scholar
  35. 35.
    Wilbrandt, W., Frei, S., Rosenberg, T. 1956. The kinetics of glucose transport through the human red cell membrane.Exp. Cell Res. 11:59PubMedGoogle Scholar
  36. 36.
    Zierler, K.L. 1961. A model of a poorly-permeable membrane as an alternative to the carrier hypothesis of cell membrane penetration.Bull. Johns Hopkins Hosp. 109:35PubMedGoogle Scholar

Copyright information

© Springer-Verlag New York Inc. 1976

Authors and Affiliations

  • Sherman D. Levine
    • 1
  • Ronald E. Worthington
    • 1
  1. 1.Department of Medicine, Division of NephrologyAlbert Einstein College of MedicineBronx

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