Serum gama-glutamyl transpeptidase in chronic extrahepatic cholestasis

RESUMO

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 15 and 110. 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