Mechanism of the enrichment of phosphatidylcholine in liver accompanying enzyme induction by phenobarbital

Autor: H. Kewitz, Pleul O, Schwartzkopff Th, Schwartzkopff G
Rok vydání: 1977
Předmět:
Zdroj: Naunyn-Schmiedeberg's Archives of Pharmacology. 297:275-281
ISSN: 1432-1912
0028-1298
DOI: 10.1007/bf00509272
Popis: The mechanism of the increase of phosphatidylcholine in liver, accompanying enzyme induction by phenobarbital, has been studied in rats. Using radioactively labeled precursors, the two main pathways of phosphatidylcholine biosynthesis--the CDP-choline pathway and the methylation of phosphatidylethanolamine--were analyzed after pretreatment with 4 doses of phenobarbital (80 mg/kg) on 3 consecutive days. After i.v. injection of choline [Me-3H], choline [Me-14C] or NaH2[32P]O4 the specific radioactivity (sp. act.) of phosphatidylcholine (dpm/nmol) was decreased by 60%, and after methionine [Me-3H] or ethanolamine [1.2-14C] by 40% compared to control rats. These changes are partly due to the increased concentration of phosphatidylcholine and phosphatidylethanolamine, causing the incorporated precursors to dilute, and partly to a secondary effect which leads to a reduction of the sp. act. of free choline in pretreated animals. The concentration of glycerylphosphorylcholine, one of the metabolites of phosphatidylcholine catabolism, was also diminished by almost 50%. From these results it may be concluded that the increase of phosphatidylcholine is due to a retardation of its breakdown rather than to an increase of its synthesis.
Databáze: OpenAIRE