Effect of chlordecone on carbon tetrachloride-induced increase in calcium uptake in isolated perfused rat liver

Intracellular accumulation of Ca2+ can occur in the livers of animals poisoned with a toxic dose of CCl4. We have reported even greater accumulation of cytosolic Ca2+ in animals treated with an ordinarily nontoxic dose of CCl4 in combination with prior exposure to chlordecone (CD). Present studies were designed to examine if intact perfused livers obtained from animals receiving either CCl4 (100 microliter/kg, ip) alone or in combination with prior dietary exposure to 10 ppm CD for 15 days accumulated 45Ca from the perfusate. Livers obtained at 0, 1, 4, 6, 12, 24, and 36 hr after a single CCl4 injection were perfused with Krebs-Ringer bicarbonate buffer containing erythrocytes, bovine serum albumin, and dextrose. After a 15-min equilibration, 45Ca was added to the perfusate, and the perfusion was continued for 30 min. Hepatic 45Ca accumulation in CCl4-treated animals in the whole liver or in the subcellular organelles obtained from perfused liver was not significantly different from corn oil controls. In the CD + CCl4 combination treatment, 45Ca accumulation followed a biphasic pattern with the first increase at 1 hr and then a progressive rise starting at 12 hr after CCl4 administration. Mitochondrial, microsomal, and cytosolic fractions from perfused liver showed a progressive rise in 45Ca at late time periods, which is indicative of unregulated and irreversible influx of extracellular Ca2+ into these livers. These studies demonstrate that cytosolic Ca2+ progressively increases as a result of the unregulated entry of extracellular Ca2+