Effect of extracellular glucose and K+ on intracellular osmolytes and volume in a human kidney cell line.
The goal of this study was to assess the effect of extracellular glucose and K+ ((K)o) on the intracellular osmolyte content and cell volume maintenance and regulation in a human embryonic kidney cell line (tsA201a). Cell volume maintenance was studied by isotonic (313 +/- 5 mOsm) replacement of culture media by a glucose-free Ringer solution containing (in mM) 0, 3, 6, or 10 K+. Cell volume regulation was studied by exposing cells to hypotonic (250 +/- 5 mOsm) glucose-free Ringer solution containing the various (K)o. The results showed that: 1) intracellular osomlyte content (i.e. Na+, Cl-, Urea and free amino acids (FAA)) and cell volume increased when culture media was replaced with isotonic Ringer at all (K)o; 2) osmolyte content decreased with continuous exposure to isotonic Ringer at all (K)o but cell volume changes depended on (K)o. Volume recovery occurred at 6 and 10 mM K+; 3) exposure to hypotonic Ringer induced swelling at all (K)o followed by a reduction in measured intracellular osmolytes. Regulatory volume decrease occurred in 6 or 10 mM K+ but swelling continued in 0 or 3 mM K+; and 4) addition of ouabain produced swelling without recovery under iso- and hypotonic conditions. These results indicate that the removal of extracellular glucose produced a transient inhibition of the Na+/K+ ATPase resulting in a transient increase in the intracellular content of Urea, FAA and cell volume and (K)o regulated an as yet unidentified intracellular osmolyte.
Hubert
Marcy D
MD
Dept. of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
Indyk
Elisabeth
E
Pena-Rasgado
Cecilia
C
Pierce
Sydney K
SK
Rasgado-Flores
Hector
H
Garber
Sarah S
SS
D002460:Cell Line; D048429:Cell Size; D005110:Extracellular Space / Q000378:metabolism; D005453:Fluorescence; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*
D005947:Glucose; D011188:Potassium