[Calcium homeostasis during thymocyte apoptosis. I. Increase in cytosolic Ca2+ concentration at the early stage of apoptosis induced by hydrogen peroxide].
The concentration of free cytosolic Ca2+ ([Ca2+]i), 45Ca2+ entry and the level of reduced glutathione (GSH) after x-irradiation in a dose of 4.5 Gy or 0.1 mM H2O2-treatment were investigated in isolated rat thymocytes during the period preceding electrophoretically detected DNA intranucleosomal fragmentation. Using fura-2 it was shown that the level of [Ca2+]i in X-irradiated thymocytes was not changed as compared with the control, while the GSH content was increased. The gradual increase in [Ca2+]i along with GSH level falling was detected in the H2O2-treated cells. 45Ca2+ entry in the cells exposed to apoptogenic stimuli was not enhanced. After addition of H2O2 to the cells previously treated with thapsigargin further [Ca2+]i increase in both normal and nominally calcium-free medium was detected. Cyclosporine A inhibited Ca2+-mobilizing effect of H2O2, but did not prevent it completely. The role of intracellular calcium depots in calcium homeostasis disturbance during oxidative stress and apoptosis is discussed.
Grebinyk
D M
DM
Koval'
T V
TV
Matyshevskaia
O P
OP
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D053938:DNA Fragmentation / Q000187:drug effects / Q000528:radiation effects; D006706:Homeostasis / Q000187:drug effects* / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D014965:X-Rays
D006861:Hydrogen Peroxide; D002118:Calcium