Effects of special blue fluorescent light on hepatic mixed-function oxidase activity in the rat.

Phototherapy has been widely used in the treatment of neonatal hyperbilirubinemia. Recent reports, however, have indicated that fluorescent light may be toxic and mutagenic to mammalian cells. these findings suggest possible long-term side effects with the use of phototherapy. This study was undertaken to determine the effects of phototherapy on hepatic microsomal enzyme activity. The exposure of Sprague-Dawley and Gunn rats to special blue fluorescent light at an average irradiance of 1,200 microW/cm2 resulted in no significant changes in liver microsomal enzyme activity for aniline hydroxylase, p-nitroanisole-O-demethylase, ethylmorphine-N-demethylase, cytochrome c reductase or the quantity of cytochrome P-450. A significant decrease in aniline hydroxylase and p-nitroanisole-O-demethylase activity was observed when liver microsomes were exposed in vitro to special blue fluorescent light. Photoactivated bilirubin did not effect the activity of the mixed-function oxidase enzymes measured under the conditions of this study.