Effects of zinc and cadmium on apoptotic DNA fragmentation in isolated bovine liver nuclei.
Isolated nuclei from mammalian cells contain a calcium-dependent endonuclease. The produced DNA fragmentation is a necessary step in the sequence of events resulting in apoptosis (programmed cell death). We report here that zinc and cadmium inhibit the calcium-dependent endonuclease. The essential metal ion zinc may counterbalance the calcium-mediated apoptosis. In contrast to zinc, cadmium alone stimulates the endonuclease by replacing calcium. Thus cadmium exerts a dual effect: micromolar concentrations inhibit the apoptotic endonuclease in the presence but activate the enzyme in the absence of calcium.
Department of Biology and Chemistry, University of Bremen, Germany.
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Lohmann
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Beyersmann
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002104:Cadmium / Q000494:pharmacology*; D002417:Cattle; D002467:Cell Nucleus / Q000187:drug effects* / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004720:Endonucleases / Q000037:antagonists & inhibitors; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D015032:Zinc / Q000494:pharmacology*
D002104:Cadmium; D004247:DNA; D004720:Endonucleases; D015032:Zinc