Mechanisms of petroleum hydrocarbon toxicity: destruction of liver microsomal and mitochondrial calcium pump activities by a Prudhoe Bay crude oil.

Administration of Prudhoe Bay crude oil (PBCO) to rats resulted in an abrupt drop in liver mitochondrial and microsomal ATP-dependent calcium uptake activity. Also, in vitro incubations of either mitochondria or microsomes in the presence of a dimethyl sulfoxide (DMSO) extract of PBCO resulted in a dose-dependent inhibition of calcium influx. The release of calcium from calcium-loaded mitochondria and microsomes was also observed in the presence of the PBCO extract. At concentrations which effect calcium sequestration, the PBCO extract produced swelling of mitochondria. Microsomal ATPase activity in the presence or absence of calcium was unaffected by PBCO. The results indicate that increased permeability of the membranes to calcium is a contributory factor in the inhibition of calcium uptake by PBCO.