|
|
|
|
|
|
|
||
The Journal of General Physiology, Vol 68, 137-143, Copyright © 1976 by The Rockefeller University Press
ARTICLES |
A Finkelstein
In artificial lipid bilayer membranes, the ratio of the water permeability coefficient (Pd(water)) to the permeability coefficient of an arbitrary nonelectrolyte such as n-butyramide (Pd(n-butyramide)) remains relatively constant with changes in lipid composition and temperature, even though the individual Pd's increase more than 100- fold. I propose that this is a general rule that also holds for the lipid bilayers of cells and tissues, and that therefore if Pd(water)/Pd(solute greatly exceeds the value found for artifical lipid bilayers (where "solute" is a molecule, such as 1,6 hexanediol or n- butyramide, that crosses the cell membrane by a solubility-diffusion mechanism without the aid of a special transporting system), then water crosses the cell membrane via aqueous pores. Applying this criterion to the toad urinary bladder, we find that even in the unstimulated bladder, water probably crosses the luminal membrane primarily through small aqueous pores, and that this almost certainly the case after antidiuretic hormone (ADH) stimulation. I suggest that ADH stimulation ultimately leads either to formation (or enlargement) of pores, by the rearrangement of preexisting subunits, or to an unplugging of these pores.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  O. A. Candia, L. J. Alvarez, and A. C. Zamudio Regulation of water permeability in rabbit conjunctival epithelium by anisotonic conditions Am J Physiol Cell Physiol, April 1, 2006; 290(4): C1168 - C1178. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Kachadorian, J Muller, S. Rudich, and V. DiScala Temperature dependence of ADH-induced water flow and intramembranous particle aggregates in toad bladder Science, August 31, 1979; 205(4409): 910 - 913. [Abstract] [PDF]
|
|
|
|
