Serum gama-glutamyl transpeptidase in chronic extrahepatic cholestasis

Studies in the literature have shown the inhibitory action action of bilirubin on serum gama-glutamyl transpeptidase (CGT) activity. In spite of this, CGT is a sensitive diagnostic indicator, comparable to alkaline phosphatase for the diagnosis of chronic extrahepatic cholestais (CEHC). To evaluate the relationship of bilirubin, alkaline phosphatase (AP) activity and GGT activity in CEHC we studied 30 patients with CEHC divided into two groups: A, 14 male and female subjects with bilirubin levels of 10.1 to 44 mg/dl. Serum GGT activity was meaured by diluting serum samples 1:5 and 1:10. GGT values were equivalent in the two groups, there was no correlation between bilirubin and GGT (r = +0.179, P > 0.01) and there was a significant correlation between GGT and AP(r = +0.627, P < 0.01). The present results show that, if GGT inhibition by bilirubin did occur, this inhibitions was not sufficient to prevent the increase in serum GGT levels and that the sensitivity of GGT as a marker for CEHC is simular to that of alkaline phosphatase

Inhibitory effect of different anticoagulants on gamma-glutamyl transpeptidase activity

Increased gama-glutamyl transpeptidase (GGT) levels have been observed in pacients with several types of liver diseases. However, since GGT activity can be inhibited or incrased by several substances, the interpretation of these increased levels should be made with caution. The present study was designed to determine plasma GGT activity in blood samples obtained from 24 adult volunters (13 males and 11 females aged 20 to 40 years) with the use of three different anticoagulants, i.e., ethylenediaminetetraacetic acid (EDTA), calcium fluoride and calcium citrate, and to compare it with GGT activity in serum obtanied from the same blood samples. Serum GGT activity wa significantly higher than plasma GGT activity (P < 0.001) and singnificantly higher in men than in women (P < 0.05), though plasma GGT activity was similar for both sexes

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 transminase 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<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 increase thereafter

Effect of hepatic artery ligation on liver metabolism in rats

The rats an experimental model of orthotopic liver transplant that does not need arterial revascularization of the transplanted liver. the objective of the present study was to investigate the effect of hepatic artery ligation on hepatic metabolism in rats. After 2, 3, or 24 h hepatic artery ligation, no significant differences in serum levels of alanine aminotransferase were observed. Bile flow decreased significantly 3 h after arterial ligation (P < 0.05) and returned to normal after 24 h (P < 0.05)

Heparin-induced increase in plasma and serum gama-glutamyl transpeptidase activity

Gama-Glutamyl transpeptidase (GGT) activity may be a sensitive index of hepatobiliary dysfunction. GGT activity, however, has been shown to be affected by several factors in different clinical situations. The present study was designed to determine the effect of heparin on serum and plasma GGT activity. Blood samples were collected from 15 normal male Wistar rats weighing 200-250 g for the determination of GGT activity in plasma prepared with heparin (group P(H),N = 10), in serum (group S,N = 15) and in serum with heparin added (group S + H,N = 10). GGT activity was 45.1 + or - 9.5 U/l (mean + or - SD) for serum compared with 161.2 + or - 46.1 U/l for serum plus heparin and 93.3 + or - 30.9 U/l for plasma prepared with heparin. The mean for each group was significantly different from the means for the other groups. These data demonstrate that GGT activity measurements should be made on serum in the absence of heparin, which produces elevated results