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Cholesterol and bile acid synthesis: Utilization of D 2 O for metabolic studies
Author(s) -
Javitt Norman B.,
Javitt Joel I.
Publication year - 1989
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200180820
Subject(s) - deuterium , chenodeoxycholic acid , cholesterol , chemistry , bile acid , in vivo , in vitro , tritium , hamster , biochemistry , biology , microbiology and biotechnology , physics , quantum mechanics , nuclear physics
Human fibroblasts and hepatoma (Hep G2) cells were grown in media containing 25% D 2 O. Cholesterol extracted from the cells and bile acids obtained from the media were analyzed by gas chromatography/mass spectrometry (GC/MS). Fibroblasts that were transferred serially in media containing D 2 O continued to grow and to synthesize cholesterol enriched in deuterium. The observed distribution of deuterium‐enriched species of cholesterol corresponded to a distribution that was calculated based on C = 27, 13 C = 1.107%, D 2 O/H 2 O = 0.25, hydrogen derived from water = 20, and is in agreement with the concept that deuterium incorporation occurs randomly and represents mostly the NADPD/NADPH ratio in the medium. The deuterium enrichment of cholesterol from hepatoma cells indicated a shift of the most abundant species from m/z 373 to m/z 375, which corresponds more closely to the derivation of 25 hydrogens from water and implies the formation of deuterated acetate in the medium. Analysis of chenodeoxycholic acid, the predominant bile acid synthesized by Hep G2 cells in vitro , indicates its derivation from both pre‐formed and newly synthesized cholesterol and that A ring transformation from cholesterol utilizes deuterium derived from water. Analysis of the bile acids derived from hamster bile following the administration of D 2 O confirms that similar events occur in vivo .