Serum transaminase levels in the acute phase of chronic extrahepatic cholestasis.

Serum alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) levels are normal or discretely increased in rats with chronic extrahepatic cholestasis (CEHC). During the acute phase (first 72 h after biliary obstruction), however, serum transaminase values are quite elevated due to a mechanism not yet fully elucidated. Thus, this is a good experimental model, not involving hepatocellular necrosis, for the study of serum ALT and AST levels during the acute phase of CEHC. Male Wistar rats (250-350 g) were divided into two groups: group A (N = 60) was submitted to sham operation for bile duct ligation (BDL), and group B (N = 60) was submitted to BDL. Thirty and 120 min after BDL there was a 1.5-fold increase in both serum ALT and AST levels compared to sham-operated rats (P less than 0.05). Serum ALT levels were higher than AST levels as early as 30 min after BDL and the highest serum values for both transaminases were observed at 360 min which was also the last value measured. Serum AST levels increased 120 min after BDL, with no further significant increases thereafter.