[Changes in cytosol Ca(2+)-, Mg(2+)-, H(+)-, N(+)-, and K(+)-concentrations in cultivated hepatocytes in hypoxic conditions].
OBJECTIVE
It is assumed that disturbances of cellular ion homeostasis, especially an increase in the cytosolic Ca2+ concentration, are of decisive importance for hypoxic cell injury. The aim of this study is the determination of alterations in the cytosolic Ca2+, Mg2+, H+, Na+ and K+ concentration in cultured hepatocytes during hypoxia.


METHODS
The alterations of ion homeostasis under hypoxic conditions were studied in primary cultures of isolated rat hepatocytes by using fluorescence microscopy.


RESULTS
The measurements of cytosolic Ca2+ concentration showed no alterations during the first 3-4 h of hypoxia. About 1-2 h before cell injury became evident Ca2+ increased from 147 +/- 28 to 385 +/- 31 nM. Similarly the cytosolic Mg2+ concentration increased from 0.63 +/- 0.05 to 1.42 +/- 0.11 mM in a late stage of hypoxia. In contrast, the cytosolic Na+ concentration increased continuously from 16 +/- 2 mM at start to 76 +/- 9 mM after 5 h of hypoxic conditions. The cytosolic K+ concentration remained constant for 2 h (129 +/- 7 mM) but then decreased down to 31 +/- 18 mM. The intracellular H+ concentration increased slightly under hypoxic conditions, the pH decreased from 7.35 +/- 0.02 to 7.19 +/- 0.04.


CONCLUSIONS
The results indicate that cytosolic Ca2+ plays only a minor role in the pathomechanism of hypoxic hepatocellular injury but suggest an important role of the cytosolic Na+ concentration in this process.
Institut für Physiologische Chemie, Universitätsklinikum Essen.
M
M
Brecht
H
H
de Groot
D000136:Acid-Base Equilibrium / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015687:Cell Hypoxia / Q000502:physiology*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D006706:Homeostasis / Q000502:physiology; D008099:Liver / Q000166:cytology*; D008274:Magnesium / Q000378:metabolism*; D008297:Male; D008856:Microscopy, Fluorescence; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism*
D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium
Veränderungen der cytosolischen Ca(2+)-, Mg(2+)-, H(+)-, N(+)- und K(+)-Konzentrationen in kultivierten Hepatozyten unter hypoxischen Bedingungen.