Effects of alloxan and streptozotocin on calcium transport in isolated mouse liver mitochondria.
The effect of alloxan and streptozotocin on the fluxes of Ca2+ in isolated mouse liver mitochondria was studied with dual wave-length spectrophotometry, using antipyrylazo III as metallochromic indicator. Streptozotocin had no effect on Ca2+ uptake, whereas alloxan inhibited the initial rate and extent of Ca2+ influx in a way dependent on the duration of preincubation, and occurrence of Pi in the reaction mixture. A rapid release of Ca2+ followed upon addition of either FCCP or alloxan after the reaction had been started. When added to preloaded mitochondria, alloxan induced a concentration dependent release of Ca2+. The data suggest that alloxan induces an initial release of mitochondrial Ca2+, which is followed by inhibition of Ca2+ influx. The initial release may be due to uncoupler activity induced by alloxan, and the inhibition of Ca2+ influx may be a consequence of inhibited Pi transport.
D000496:Alloxan / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D013311:Streptozocin / Q000494:pharmacology*; D013997:Time Factors
D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D013311:Streptozocin; D000496:Alloxan; D002122:Calcium Chloride; D002118:Calcium