The Comparative Activity of Some Enzymes in Sheep, Cattle and Rats—Normal Serum and Tissue Levels and Changes During Experimental Liver Necrosis

A survey has been carried out of the distribution of some enzymes in the tissues, whole blood and serum of normal sheep, cattle and rats. The enzymes studied were glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), glutamate dehydrogenase (GD), L-lactate dehydrogenase (LD) and TPN-dependent isocitrate dehydrogenase (ICD). Carbon tetrachloride was given orally to 4 sheep, 2 calves, 1 cow and 26 rats. Centrilobular liver necrosis was observed histologically in liver samples obtained post-mortem from the rats, and by biopsy from the cow, 3 of the sheep and both calves. The activities of the enzymes were assayed in serum collected at intervals from these animals. These activities, except of GPT in the cow, sheep and calves, increased during the period of necrosis of liver cells up to 48 hours. There was a tendency for enzymes most active in liver to increase most. There also appeared to be some relationship between the amount of the increase and the extent of hepatic necrosis. The pattern of serum enzyme elevations was similar in the cow, sheep and calves and differed from that in rats. The serum enzyme most affected by liver damage was GPT in the rat and GD in sheep and calves.