Ionomycin

Ionomycin causes a rapid rise in cytosolic Ca2+ that is due to both a release of cytosolic Ca2+ stores and Ca2+ influx. Ionomycin also activates (2 microM) and primes (20-200 nM) the PMN oxidase. Ionomycin is shown to be an effective ionophore for Ca2+ in rat liver mitochondria. The ionomycin-induced efflux of Ca2+ across the inner membrane is more sensitive to loading the mitochondria with Ca2+ than was efflux catalyzed by A23187.