Apparent lack of correlation between the loss of cytochrome P-450 in hepatic parenchymal cell culture and the stimulation of haem oxygenase activity

The hypothesis that the stimulation of haem oxygenase activity in cultured adult rat liver parenchymal cells is intimately associated with the accelerated breakdown of the haemoprotein cytochrome P-450 was examined. Even though the time course of the loss of cytochrome P-450 and the stimulation of haem oxygenase activity were found to be compatible with this hypothesis, further work however showed that high levels of cytochrome P-450 could be maintained in liver cell culture in the face of high haem oxygenase activities.