EFFECTS OF RABEPRAZOLE, A GASTRIC PROTON PUMP INHIBITOR, ON BILIARY AND HEPATIC LYSOSOMAL-ENZYMES IN RATS

The effects of rabeprazole (E3810), omeprazole and chloroquine on hepa tic lysosomal function were studied. After chloroquine (50 mg/kg), rab eprazole (5 mg/kg) or omeprazole (5 mg/kg) was given intraperitoneally to rats for 6 days, the bile was collected via a bile duct cannula fo r 5 hr, and hepatic and biliary lysosomal enzyme (N-acetyl-beta-glucos aminidase and beta-galactosidase) activities were measured. The latenc y (an index for the hepatic lysosomal membrane integrity) was calculat ed from the N-acetyl-beta-glucosaminidase activity. The biliary consti tuents and plasma concentrations of lipids were also measured. The adm inistration of chloroquine significantly increased hepatic and biliary lysosomal enzyme activities, but did not affect the lysosomal enzyme latency, hepatic and biliary protein content or bile flow. It signific antly decreased the bile acid level. On the other hand, the administra tion of rabeprazole and omeprazole did not alter the lysosomal enzyme activities, lysosomal enzyme latency, protein content in liver or live r weight. Furthermore, no significant differences were observed in bil iary lysosomal enzyme activity, protein content, bile flow, biliary co nstituents or in the plasma concentrations of lipids between the drug groups (rabeprazole or omeprazole) and the control group. The results of the present study indicate that rabeprazole, like omeprazole, does not influence hepatic lysosomal function.