The impairment of mitochondrial function by Triton X-100.A study of mitochondrial respiration and energy-dependent swelling

Abstract

Coupled and uncoupled respiration, and energy-dependent phosphate swelling have been studied in rat liver mitochondria in the presence of various concentration of Triton X-100.Detergent concentrations up to 10(-5) M do not affect any of the processes under study.At 10(-5) M, Triton X-100 produces a slight decrease of coupled respiration and a considerable inhibition of mersalyl-induced shrinking in swollen mitochondria.Increasing the surfactant concentration to 10(-4), coupled as well as uncoupled O2 consumption is decreased, succinate-dependent phosphate swelling is inhibited and an energy-dependent phosphate swelling in the absence of valinomycin is observed.At 2 X 10(-4) M.Triton X-100, ATP- dependent phosphate swelling is abolished, and passive swelling may be induced by various ions.Higher detergent concentrations do not allow observation of any of these events.On the basis of these results, a model of membrane-detergent interaction is proposed.