Bile pigments and bilirubin UDP-glucuronyl transferase during the metamorphosis of Rana catesbeiana tadpoles.

The major bile pigments in Rana catesbeiana tadpoles was bilirubin IX alpha. The concentration of bilirubin IX alpha increases in bile and plasma during metamorphosis. Bilirubin IX alpha and biliverdin IX alpha were also present in the bile of tadpoles. Bilirubin UDP-glucuronyl transferase activity was present in the livers of all tadpoles examined. Bilirubin UDP-glucuronyl transferase activity increases slightly during spontaneous metamorphosis and increases approximately 2-fold during T3-induced metamorphosis.