Chloramphenicol and ampicillin-induced changes in rat hepatic esterase and amidase activities

The influence of ampicillin and chloramphenicol administered intraperitoneally singly or in combination on the protein content and the activities of hepatic esterase and amidase have been investigated in rats. The results have been compared to the effects of phenobarbitone (inducer) and p-nitrophenyl-phosphate (inhibitor) of hepatic hydrolases. Ampicillin pretreatment reduced protein level and amidase activity by 3.5% each but caused a significant increase (8.1%) in total esterase activity compared to controls. Chloramphenicol treatment caused an overall decrease in protein level, esterase and amidase activities respectively by 11%, 11%, and 35% over controls. Combined administration of both drugs resulted in a decrease in protein, esterase and amidase activities by 11.5%, 12.5%, and 41.2% respectively, thus mimicking the effects obtained with chloramphenicol alone. The changes induced by administration of the drugs particularly in combination on the constituent enzymes of rat hepatic hydrolases may affect the ability of the body to deal with exposure to environmental chemicals if extrapolated to man.