[Activity of key enzymes of heme synthesis and degradation and contents of cytochromes b5 and P-450 in rat liver].
The relation between the delta-aminolevulinate-synthase and heme-oxygenase activities and the contents of cytochromes b5 and P-450 in rat liver after phenobarbital and CoCl2 injections was studied. Two hours after a single injection of phenobarbital the delta-aminolevulinate-synthase activity is increased, showing a further rise after 24 hrs. The content of cytochrome b5 is not changed, while that of cytochrome P-450 is increased 24 hrs after the injection. The heme-oxygenase activity remains unaffected thereby. The increase in the enzyme activity and cytochrome P-450 content induced by phenobarbital is eliminated by a preliminary administration of actinomycin D. The administration of CoCl2 is accompanied by a decrease in the delta-aminolevulinate-synthase activity after 2 hrs and its further increase after 24 hrs. The heme-oxygenase activity shows a sharp rise 24 hrs after the injection. The rise in the delta-aminolevulinate-synthase activity induced by CoCl2 is removed by actinomycin D. CoCl2 decreases the content of cytochromes b5 and P-450 24 hrs after the injection. It is assumed that the correlation between the delta-aminolevulinate-synthase activity and cytochrome P-450 content is observed only in the case when the heme-oxygenase activity is not increased. The cytochrome b5 content is independent of the changes in the activity of the key enzyme of heme synthesis and depends to a certain extent on the rate of heme degradation by heme-oxygenase.
D000624:5-Aminolevulinate Synthetase / Q000378:metabolism*; D000818:Animals; D003035:Cobalt / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism*; D015786:Cytochromes b5; D004790:Enzyme Induction; D006418:Heme / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats
D003580:Cytochromes; D003035:Cobalt; D006418:Heme; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D006419:Heme Oxygenase (Decyclizing); D000624:5-Aminolevulinate Synthetase; D010634:Phenobarbital
Aktivnost' kliuchevykh fermentov sinteza i raspada gema i soderzhanie tsitokhromov b5 i P-450 pecheni krys.