Inability of tributyltin-induced chloride/hydroxyl exchange to stimulate calcium transport in mitochondria isolated from flight muscle of the sheep blowfly Lucilia cuprina.
Tributyltin in the concentration range 1-4mum failed to stimulate Ca(2+) transport by Lucilia flight-muscle mitochondria in a medium containing KCl and respiratory substrate but devoid of P(i), despite its promotion of a rapid Cl(-)/OH(-) exchange. When 2mm-P(i) was present, concentrations of tributyltin greater than 1mum inhibited the initial rate of Ca(2+) transport and induced efflux of the ion from the mitochondria in Cl(-)- or NO(3) (-)-containing media. Lower concentrations had little effect. Oligomycin added at up to 10mug/mg of mitochondrial protein had no effect on Ca(2+) transport. By contrast, approx. 0.3mum-tributyltin completely inhibited respiration supported by alpha-glycerophosphate in either the presence or absence of added ADP. The data suggest that tributyltin can inhibit Ca(2+) transport in Lucilia flight-muscle mitochondria other than by facilitating a Cl(-)/OH(-) exchange or producing an oligomycin-like effect.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D004175:Diptera / Q000378:metabolism*; D005426:Flight, Animal; D006878:Hydroxides / Q000378:metabolism; D066298:In Vitro Techniques; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism*; D014220:Trialkyltin Compounds / Q000494:pharmacology*
D002712:Chlorides; D006878:Hydroxides; D014220:Trialkyltin Compounds; D002118:Calcium