AROCLOR 1254 TOXICITY TO MICE LIVER MEMBRANE ATPASES

Abstract

Present communication reports the sub-acute dose and exposure duration dependent effects of Aroclor 1254 on total, Na+, K+, Ca++ and Mg++-ATPases of the mouse liver cells. The study tests two hypotheses, (a) whether the sublethal dose or the exposure duration dependent in vivo exposure of hydrophobic PCB (Aroclor 1254) affects the hydrophilic membrane-bound ion dependent ATPases of the liver cells and (b) if a response was observed, whether it was a direct effect of the toxicant on the membrane bound enzymes systems. To check these hypotheses, two groups of mice were subjected to different sublethal oral doses (0.1 and 1 mg kg-1 bw d-1) of Aroclor 1254 for three exposure durations (4, 8 and 12 days). Specific activities of four membrane bound ATPases were estimated from the liver tissue of the aroclor treated mice and compared with a control. Results indicated significant dose as well as duration dependent changes in the enzymatic levels in the hepatic cells of the exposed mice. In most of the cases, the enzyme activity was initially inhibited followed by stimulation after longer exposure duration. The observations suggested that the alteration in the enzyme activity was possibly due to the oxidative stress generated by Aroclor 1254. The results indicated that the membrane bound hydrophilic ATPases were indeed affected by the hydrophobic Aroclor, but the effects were possibly indirect through complex chain of reactions exhibited by the cells.