Synthesesteigerung und Abbauhemmung bei der Vermehrung der mikrosomalen Cytochrome P-450 und b-5 durch Phenobarbital

Translated title of the contribution: Increased synthesis and inhibited breakdown during the increase of microsomal cytochromes P-450 and b-5 after phenobarbital

Helmut Greim

Research output: Contribution to journalArticlepeer-review

94 Scopus citations

Abstract

Heme moieties of microsomal rat liver cytochromes P-450 and b-5 were labeled with.14C-Aminolevulini cacid. The half life of the b-5 heme radioactivity was found to be 45 hrs, that of the P-450 heme radioactivity was 22 hrs. Treatment of fed rats with Phenobarbital (80 mg/kg i.p. and 1‰ PB in the drinking water) for 48 hrs increased the concentration of cytochrome P-450 up to 200%, only by induced synthesis. In starved rats treated with Phenobarbital, P-450 concentration was increased up to 400%, by both induced synthesis and inhibition of breakdown. Microsomal P-450 cytochrome was determined in rat liver homogenate and in suspensions of rat liver microsomes. The amount of P-450 obtained in the isolated microsomal fraction was compared with the P-450 content in the liver homogenate. Since P-450 is a microsomal hemoprotein this relation can be correlated with the microsomal protein, in order to to calculate the real content of microsomal protein in the liver homogenate. It was found to be 65 mg/g of liver, demonstrating, that 31% of the 209 mg of total protein/g of liver consists if microsomal protein.

Translated title of the contributionIncreased synthesis and inhibited breakdown during the increase of microsomal cytochromes P-450 and b-5 after phenobarbital
Original languageGerman
Pages (from-to)261-275
Number of pages15
JournalNaunyn-Schmiedeberg's Archives of Pharmacology
Volume266
Issue number3
DOIs
StatePublished - Jun 1970
Externally publishedYes

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