Induction of UDP-glucuronyl transferase mRNA in embryonic chick livers by phenobarbital.

Administration of phenobarbital to chick embryos increased hepatic microsomal UDP-glucuroyltransferase activity some 25-fold. The large phenobarbital-induced increase of UDP-glucuronyltransferase activity was correlated to an equivalent increase of immunochemically measurable UDP-glucuronyltransferase protein. Poly(A+) RNA isolated from the livers of chick embryos treated with either phenobarbital or saline was translated in vitro. Immunochemical analysis of the translation products indicated that phenobarbital induced a 30-fold increase in UDP-GT mRNA. Fractionation of hepatic poly(A+) RNA from phenobarbital-treated chick embryos by sucrose density gradient centrifugation indicated that the size of the UDP-GT mRNA was 21S. These data show that phenobarbital induction of chick embryo liver UDP-glucuronyltransferase activity correlates with a similar large increase in the level of translatable mRNA for this enzyme.