Serum levels of bilirubin and biliverdin in the sea lamprey, Petromyzon marinus L., before and after their biliary atresia.

1. The sera of ammocoetes, juvenile adults, and upstream migrants of the sea lamprey, Petromyzon marinus L., were analyzed for the presence of the bile pigments, biliverdin and bilirubin. 2. Bile pigment was not detected in the sera of ammocoetes. 3. After biliary atresia (degeneration of bile ducts at metamorphosis), bilirubin and biliverdin were detected in the sera of both juvenile adults and upstream migrants. 4. These data suggest that lampreys have some bile stasis following biliary atresia, but also that they likely have alternate pathway(s) for bile pigment elimination.