Serum level of biliary glycoprotein I, a determinant of cholestasis, of similar use as gamma-glutamyltranspeptidase.

Biliary glycoprotein I (BGP I), a constituent of normal bile and serum, is a glycoprotein (mol. wt. approximately 90,000) containing about 40% carbohydrate. Serum BGP I (S-BGP I) was determined by means of a double-antibody radioimmunoassay in patients with liver and gastrointestinal disease and in healthy individuals. The serum levels of five liver enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase (S-ALP), gamma-glutamyltranspeptidase (S-GT), and lactic dehydrogenase), bilirubin (total and conjugated), and bile acids (cholic and chenodeoxycholic acid) were determined in parallel. Healthy individuals had 0.5 +/- 0.3 mg/l of S-BGP I (mean +/- 2 S.D.; range, 0.2-0.9 mg/l). Most patients with liver disease (chronic hepatitis, alcoholic cirrhosis, primary biliary cirrhosis) had elevated levels, up to 5-10 times the upper reference limit, whereas most patients with gastrointestinal disease (ulcerative colitis, Crohn's disease, other GI diseases) had normal values. In patients with liver disease S-BGP I was positively correlated (p less than 0.0005) to S-GT. In primary biliary cirrhosis a positive correlation (p less than 0.005) between S-BGP I and S-ALP was also obtained. All other comparisons between S-BGP I and the other liver function tests showed non-significant correlations. It is concluded that S-BGP I is a determinant of cholestasis of similar use as S-GT.