Abstract
Ornithine carbamoyltransferase (OCT, EC 2.1.3.3) is a key enzyme in the urea cycle and is present almost exclusively in the liver mitochondria. This organ specificity is used as a clinical test to detect hepatocelluar damage. In this study, OCT activity was determined based on diacetylmonoxime reaction, simultaneously with other enzymes such as GOT, GPT, ALP, GGTP and LDH, in 119 cases of malignancy and in 98 normal subjects, to clarify its clinical significance.
The correlation coefficiency of OCT and GOT in malignancy was the highest (r=0.735). Graphic displays of 6 serum enzymes, OCT, GOT, GPT, ALP, GGTP and LDH, demonstrated peculiar pattern for carcinoma of the stomach, the lung, and the breast, respectively. Notably, the pattern of graphic displays of serum enzymes was different between hepatocellular carcinoma and metastatic liver carcinoma. In the serial determi-nation of serum enzymes in a patient with hepatocellular carcinoma, correlative elevation of OCT and GOT was observed during hepatic encephalopathy. Measurement of OCT in the serum is of considerable value in the differential diagnosis of malignant disease af-fecting the liver and hepatocellular carcinoma.