Ion transport in rat liver mitochondria: the effect of the incubation medium osmolarity.
A decrease in the incubation medium osmolarity from 320 to 120 mosM reverses the pH dependence of K+ efflux from rat liver mitochondria. The K+ efflux is no longer inhibited by oligomycin and a free radical scavenger butylhydroxytoluene. At 320 mosM, the addition of carbonyl cyanide 3-chlorophenylhydrazone (CCCP) accelerates the K+ efflux, while EGTA inhibits it. At 120 mosM these CCCP and EGTA effects are reversed. In either case the K+ efflux is inhibited by Mg2+. The decrease in osmolarity changes the ruthenium red-insensitive Ca2+ efflux in the same manner. It has thus been shown that the modification of the mitochondrial structure by changing the incubation medium osmolarity results in a qualitative alteration of the systems regulating the K+ and Ca2+ effluxes.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002412:Cations; D004533:Egtazic Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008930:Mitochondria, Liver / Q000378:metabolism*; D009994:Osmolar Concentration; D011188:Potassium / Q000378:metabolism*; D051381:Rats
D002412:Cations; D004533:Egtazic Acid; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D011188:Potassium; D002118:Calcium