Tributyltin and mitochondria: new evidence in favour of an uncoupling mechanism

In this paper we give further evidence in favour of the proposal that the o rganometal tributyltin compound is an uncoupler of oxidative phosphorylatio n. Since new experiments indicate that tributyltin is an inhibitor of the m itochondrial respiratory chain, we have analysed the interactions of tribut yltin with ATP energised mitochondria. Results indicate that the tributylti n compound behaves as uncoupler in a chloride-free medium, thus excluding t hat in this condition tributyltin is a Cl-/OH- exchanger. Since tributyltin , like many metals, induces the opening of a Cyclosporine-sensitive channel , we have further analysed this situation. (C) 2000 Elsevier Science S.A. A ll rights reserved.