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Updated: Aug 17, 2026

Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
Published on: June 29, 2011
Cytochrome c release and caspase activation in hydrogen peroxide- and tributyltin-induced apoptosis
H Stridh1, M Kimland, D P Jones
1Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Stockholm, Sweden.
Abstract:
The ability of H2O2 and tributyltin (TBT) to trigger pro-caspase activation via export of cytochrome c from mitochondria to the cytoplasm was investigated. Treatment of Jurkat T lymphocytes with H2O2 resulted in the appearance of cytochrome c in the cytosol within 2 h. This was at least 1 h before caspase activation was observed. TBT caused cytochrome c release already after 5 min, followed by caspase activation within 1 h. Measurement of mitochondrial membrane potential (delta psi(m)) showed that both H2O2 and TBT dissipated delta psi(m), but with different time courses. TBT caused a concomitant loss of delta psi(m) and release of cytochrome c, whereas cytochrome c release and caspase activation preceded any apparent delta psi(m) loss in H2O2-treated cells. Thus, our results suggest that different mechanisms are involved in triggering cytochrome c release with these apoptosis-inducing agents.
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