Effect of glutathione on inositol 1,4,5-triphosphate-induced Ca2+ release in permeabilized hepatocytes from control and chronic ethanol-fed rats.
The effect of oxidized and reduced glutathione on inositol 1,4,5-trisphosphate (InsP3)-induced Ca2+ release from endoplasmic reticular Ca2+ stores was studied in digitonin-permeabilized hepatocytes from chronically ethanol-fed rats and pair-fed control animals. The fractional Ca2+ release induced by a subsaturating concentration of InsP3 was significantly enhanced in cells from ethanol-fed rats in the absence of a change in maximal InsP3-releasable Ca2+ pool size, and this difference was not affected by preincubation with reduced glutathione. Incubation with oxidized glutathione (1 mM) increased the efficacy of Ca2+ release by subsaturating concentrations of InsP3 in both control preparations and in cells from ethanol-fed rats. The shift in the InsP3 dose-response curve was not significantly different between the two preparations. These findings suggest that the enhanced efficacy of InsP3-induced Ca2+ release in hepatocytes from ethanol-fed rats is not caused by the oxidation of protein-bound thiol groups on the InsP3 receptor.
Nomura
T
T
First Department Medicine, Nagoya City University, Japan.
Higashi
K
K
Hoshino
M
M
Saso
K
K
Itou
M
M
Hoek
J B
JB
D000437:Alcoholism / Q000503:physiopathology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D005978:Glutathione / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008099:Liver / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000502:physiology
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D015544:Inositol 1,4,5-Trisphosphate; D005978:Glutathione; D002118:Calcium