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Sublethal oxidant stress induces a reversible increase in intracellular calcium dependent on NAD(P)H oxidation in rat alveolar macrophages
- Source :
- Archives of Biochemistry and Biophysics. 299:83-91
- Publication Year :
- 1992
- Publisher :
- Elsevier BV, 1992.
-
Abstract
- A concentration-dependent elevation of intracellular calcium ([Ca2+]i) and oxidation of NAD(P)H occurred in alveolar macrophages during exposure to sublethal tert-butylhydroperoxide concentrations (tBOOH) (or = 100 microM in 1 ml with 1 x 10(6) cells). Oxidation of NAD(P)H preceded a rise in [Ca2+]i. The elevation of [Ca2+]i was reversible at50 microM tBOOH exposure and the return to the steady state [Ca2+]i correlated temporally with repletion of NAD(P)H. At50 microM tBOOH, the changes in NAD(P)H and [Ca2+]i were sustained. The relative contributions of NADPH and NADH oxidation were examined by varying the substrates supplying reducing equivalents and by inhibiting glutathione reductase activity. The results suggested that at50 microM tBOOH, oxidation of NADPH predominated, while at50 microM tBOOH, NADH oxidation predominated. A complex relationship between the relative roles of NADPH and NADH oxidation and the elevation of [Ca2+]i was revealed: (i) reversible oxidation of NADPH is associated with the initial and reversible elevation of [Ca2+]i at50 microM tBOOH; (ii) the sustained elevation of [Ca2+]i at50 microM tBOOH correlates with the sustained oxidation of NADH; and (iii) the changes in [Ca2+]i did not depend on influx of extracellular Ca2+. We speculate that at low tBOOH, Ca2+ was released from the NADPH/NADP(+)-sensitive mitochondrial Ca2+ pool while higher tBOOH caused additional Ca2+ release from GSH/GSSG-sensitive nonmitochondrial Ca2+ pools with sustained elevation of [Ca2+]i due to decreased mitochondrial Ca2+ reuptake.
- Subjects :
- Indoles
Time Factors
Stereochemistry
Biophysics
chemistry.chemical_element
In Vitro Techniques
Biology
Calcium
Biochemistry
Calcium in biology
Rats, Sprague-Dawley
chemistry.chemical_compound
tert-Butylhydroperoxide
Macrophages, Alveolar
medicine
Extracellular
Animals
Molecular Biology
Chelating Agents
Glutathione
NAD
Oxidants
Molecular biology
Peroxides
Rats
Kinetics
Spectrometry, Fluorescence
medicine.anatomical_structure
chemistry
NAD+ kinase
Steady state (chemistry)
Pulmonary alveolus
Oxidation-Reduction
NADP
Intracellular
Subjects
Details
- ISSN :
- 00039861
- Volume :
- 299
- Database :
- OpenAIRE
- Journal :
- Archives of Biochemistry and Biophysics
- Accession number :
- edsair.doi.dedup.....1e75930d90e627d98574f598e7cb11bc