zearalenone and 6-ketocholestanol

Zearalenone (F-2) is a mycotoxin which acts as a protonophoric uncoupler in plant mitochondria [Macri, F. and Vianello, A., (1990) J. Plant Physiol. 136, 754-757]. In the present paper, the mechanism of F-2-induced uncoupling in pea mitochondria was studied. The uncoupling by F-2 was partially reversed by 6-ketocholestanol (kCh) under conditions in which kCh completely reversed the FCCP-induced uncoupling and almost did not affect the palmitate-induced uncoupling. Recoupling effects of carboxyatractylate, ADP and cyclosporin A were small and could not essentially decrease the kCh-insensitive part of F-2-induced uncoupling. It is suggested that a protein, mediating kCh-sensitive uncoupling, is involved in the F-2 effect in plant mitochondria.

Topics: Atractyloside; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Dose-Response Relationship, Drug; Estrogens, Non-Steroidal; Glutamic Acid; Ketocholesterols; Membrane Potentials; Mitochondria; Palmitic Acid; Plants; Uncoupling Agents; Zearalenone