The contribution of endogenous polyamines to the permeability transition of rat liver mitochondria.

Spermine and spermidine are present in rat liver mitochondria at the concentrations of 3.5 and 1.8 nanomoles/mg protein, respectively.

The alterations in the energy linked properties induced in rat liver mitochondria by acetylsalicylate are prevented by cyclosporin A or Mg2+.

The alterations in rat liver mitochondria induced by acetylsalicylate in the presence of low concentrations of Ca2+ (large amplitude swelling, permeability to 14C]sucrose, collapse of transmembrane potential and effluxes of endogenous Mg2+ and accumulated Ca2+) were fully prevented by either cyclosporin A or Mg2+. Cyclosporin A and Mg2+ were also capable of restoring transmembrane potential upon its decrease induced by acetylsalicylate. The loss of endogenous Mg2+ was the primary effect promoted by acetylsalicylate; the other noxious effects followed.

Inhibition of mitochondrial permeability transition by polyamines and magnesium: importance of the number and distribution of electric charges.

The protective effects of Mg2+ and various natural and synthetic polyamines on the permeability transition of isolated rat liver mitochondria have been compared. The permeability transition was induced by incubating the mitochondria in a sucrose medium at pH 7.4 in the presence of 100 microM Ca2+ and 1 mM phosphate and was monitored via the release of endogenous Mg2+, sucrose permeation, mitochondria swelling and the fall of transmembrane potential.

Anaplerotic effect of propionyl carnitine in rat heart mitochondria.

Carnitine and propionyl carnitine both increase production of 14CO2 from [1-14C]pyruvate but only the latter, in a process inhibited by malonate, increases oxygen uptake and 14CO2 evolution from [2-14C]pyruvate. Carnitine increases the rate of formation of acetyl carnitine from pyruvate to a greater extent than propionyl carnitine. These effects of carnitine and propionyl carnitine are not detectable in mitochondria (e.