ALLYL ALCOHOL CYTOTOXICITY IN ISOLATED RAT HEPATOCYTES - MECHANISM OFCELL-DEATH DOES NOT INVOLVE AN EARLY RISE IN CYTOSOLIC-FREE CALCIUM

We examined the effect of a toxic concentration of allyl alcohol (0.5 mM) on intracellular calcium concentrations in isolated rat hepatocyte s. An increase in phosphorylase a activity was evident in the hepatocy tes after 30 min of incubation with allyl alcohol, suggesting that the toxicant may produce an early rise in cytosolic free calcium. The inc rease in phosphorylase a activity was not reversed by the addition of dithiothreitol (DTT), a sulfhydryl compound that reverses the events t hat initiate cell killing by allyl alcohol. When intracellular calcium concentrations were measured directly, using fura-2 as the calcium in dicator, there was no effect of allyl alcohol on cytosolic free calciu m during the first 60 min of exposure, a critical period for developme nt of irreversible damage. Incubation with allyl alcohol did not inter fere with the measurement of intracellular calcium. The increases in c ytosolic free calcium produced by phenylephrine or ATP were similar to those reported by others and not affected by the presence of allyl al cohol. The results from this study demonstrate that increased cytosoli c free calcium is not essential for allyl alcohol-induced cytotoxicity to isolated rat hepatocytes.