Comparative effects of ionophores grisorixin, alborixin and two derivatives on K+ glutamate efflux in rat liver mitochondria.
The alkali cations discrimination on a liquid membrane electrodes system, was determined for the carboxylic ionophores grisorixin, alborixin and two derivatives, dihydrogrisorixin and hexahydroalborixin. The two antibiotics exhibited a great perference for K+. Dihydrogrisorixin again showed the selectivity curve of a carboxylic ionophore, but with a discrimination power lowered compared with grisorixin. Hexahydroalborixin had lost all the complexing properties of the natural molecule. The selectivity scales measured for cations, were directly correlated with the K+ and glutamate effluxes measured in rat liver mitochondria. The chemical modifications of the natural structures of grisorixin and alborixin resulted in a drastic reduction of their ionophoric properties. The loss of K+-glutamate might occur in two steps, the efflux of K+ catalysed by the ionophores then causing a loss of negative charges in the form of glutamate.
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D055598:Chemical Phenomena; D002621:Chemistry; D002627:Chemistry, Physical; D005971:Glutamates / Q000378:metabolism*; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology*; D007477:Ions; D008930:Mitochondria, Liver / Q000378:metabolism*; D009550:Nigericin / Q000031:analogs & derivatives / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D011714:Pyrans / Q000494:pharmacology; D051381:Rats
D000900:Anti-Bacterial Agents; D005971:Glutamates; D007476:Ionophores; D007477:Ions; D011714:Pyrans; C012708:alborixin; C010731:grisorixin; C024508:hexahydroalborixin; C024507:dihydrogrisorixin; D009550:Nigericin; D011188:Potassium