Induction of gamma-glutamyltranspeptidase-positive foci in rat liver by deoxycholic acid.

Initiating activities of the secondary bile acids, deoxycholic acid (DCA) and lithocholic acid (LCA), were examined in terms of the induction of gamma-glutamyltranspeptidase (GGT)-positive foci in rat liver. A rapid induction model of enzyme-altered foci was utilized. GGT-positive foci were clearly induced by DCA ranging from 0.05% to 0.5% in the diet. In contrast, the induction of GGT-positive foci by LCA was less pronounced and was not dose-dependent. These results suggest that DCA possesses initiating activity.