Serum gamma-glutamyl transpeptidase activity in viral hepatitis: suppression in pregnancy and by birth control pills.

gamma-Glutamyl transpeptidase (GGT) activity in serum was increased in the majority of women with viral hepatitis occurring in the first half of pregnancy. By contrast, GGT activity was abnormal less frequently and the mean value was relatively depressed, even though hepatitis was as severe, in the second half of gestation. Mean GGT activity was also lower, and abnormal values were less frequent, in nonpregnant women with viral hepatitis who were taking birth control pills (BCP). Depressed GGT is not attributable to an inhibitor in serum in women in late pregnancy or taking BCP. The data suggest that estrogen and/or progestational compounds affect liver such that less GGT is released into blood with acute hepatocellular injury. In addition, hyperbilirubinemia was found to be associated with depressed serum GGT activity, and bilirubin added to serum in vitro interfered with measured activity of the enzyme.