Changes in the male rat hepatic cytochrome P-450 level, heme oxygenase and delta-aminolevulinic acid synthase activities at various stages of life.

delta-Aminolevulinic acid synthase and heme oxygenase are closely functionally connected with the hepatic microsomal mixed function oxydase system. There is a wide range of changes in microsomal heme oxygenase activity, cytochrome P-450 level and mitochondrial delta-aminolevulinic acid synthase activity in rat livers at various stages of life. We tried to investigate the spontaneous phases of these enzymatic protein activities and the levels of cytochrome P-450 as a function of age. We noted that each of these proteins change their activity and level very characteristically during the rats' lifetime. However, correlations between heme oxygenase activity, delta-aminolevulinic acid synthase activity and cytochrome P-450 levels still need to be investigated to elucidate the mechanism of these connections.