Serum enzymes as indicators of chemically induced liver damage.

Rats were dosed with CCl4 or diethylamine to induce liver injury. The time and magnitude of peak liver injury were assessed by histopathological examination of liver specimens taken at intervals after dosing. Serum enzymes were measured at the same intervals. Serum ornithine carbamyl transferase (SOCT) activity increased at least 6-fold in animals that showed liver damage by histopathology, and fell again as the injuries resolved. Measurements of other enzymes were less sensitive. SOCT measurements appear to be as sensitive a method as histopathology for detecting liver damage caused by administering xenobiotics. Since serum enzyme measurements do not require that the animals be sacrificed, they can be used for repeated examinations of the same animals, thus increasing the likelihood of detecting transient injury.