Enzyme changes in experimental biliary obstruction

Changes in the activities of alkaline phosphatase, 5'nucleotidase and γ-glutamyl transpeptidase in serum and liver of bile-duct ligated rats were studied over a period of 8 days after operation. All three enzymes showed increased activity in the liver, but for 5'nucleotidase and γ-glutamyl transpeptidase the increases were not detectable before 48 h, whereas for alkaline phosphatase the maximum rise was at 12 h. All three activities in the serum were significantly elevated at 12 h after operation. Maximum levels were reached at 24 h for alkaline phosphatase and 5'nucleotidase but not before 48 h for γ-glutamyl transpeptidase. These results show that bile duct ligation causes an early increase in synthesis of hepatic alkaline phosphatase whereas the incresase in 5'nucleotidase and γ-glutamyl transpeptidase is delayed until the phase of bile duct proliferation. The early changes in serum activities of 5'nucleotidase and γ-glutamyl transpeptidase do not appear to be due to a rapid increase in hepatic synthesis of these enzymes.