Serum glutathione S-transferase in experimental liver damage in rats

The changes of serum glutathione S-transferase (GST) was observed after carbon tetrachloride (CCl4) administration to Wistar rats. Serum GST activity increased rapidly and reached the peak 24 hours after CCl4 administration, and decreased rapidly thereafter. Centrilobular massive necrosis was already observed at the peak time of serum GST activity. On the other hand, serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities varied slowly, and the peak time of GOT and GPT activities was 36 hours after CCl4 administration. GST-containing Y fraction obtained from rat liver was injected intravenously to control and nephrectomized rats, and the plasma disappearance of GST activity was observed. The plasma disappearance of GST activity was very rapid in the control rats. When the Y fraction obtained from 1/12 g liver was injected, no statistically significant difference in the plasma GST half lives was observed between the control and nephrectomized rats. Half life of serum GST was significantly shorter in control rats receiving the Y fraction from 1/60 g liver, comparing with that in nephrectomized rats receiving the same amount of Y fraction. From these results, serum GST is concluded to be a precise index of the early stage of hepatic necrosis in the rat, and considerable amount of GST is excreted from the kidneys, but most of the enzyme is metabolized in vivo.