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Volume changes of mammalian cells subjected to hypotonic solutions in vitro : Evidence for the requirement of a sodium pump for the shrinking phase
Author(s) -
Rosenberg Howard M.,
Shank Brenda Buckhold,
Gregg Earle C.
Publication year - 1972
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040800104
Subject(s) - tonicity , ouabain , sodium , extracellular , chemistry , osmotic concentration , osmole , percoll , distilled water , biophysics , volume (thermodynamics) , centrifugation , chromatography , biochemistry , biology , endocrinology , physics , organic chemistry , quantum mechanics
A Coulter‐orifice pulse‐height analyzer system was used to measure volume spectra of mammalian cells in suspension at different times after the addition of an equal volume of water. In appropriate hypotonic medium, cultured mammalian cells rapidly increase in volume and then shrink, more slowly, approaching their initial volumes within 20 to 30 minutes at 37.5°C. The shrinking phase was found to be reversibly inhibited by ouabain and inhibited in both K + ‐free and Na + ‐free solutions; neither choline + nor Li + could substitute for extracellular Na + in supporting the shrinking phenomenon but Rb + and Cs + were fairly good substitutes for K + . Under conditions similar to those with which the shrinking phenomenon was observed with cultured cells, it was not found with either human or mouse red blood cells. Two methods were used to determine intracellular Na + and K + content in osmotically shocked cells and in unshocked controls. An isotope equilibration method was employed with L5178‐Y mouse lymphoblasts and a chemical determination by flame photometry was used with Ehrlich ascites tumor cells. The K + content was significantly reduced and the Na + content was unchanged or somewhat increased in cells which had returned to their original volumes in hypotonic medium. The K + content was even more reduced but the Na + content was greatly increased in cells which were osmotically shocked in the presence of ouabain.