Journal ArticleDOI
Oxygen-18 exchange reactions in steroidal ketones. Determination of relative rates of incorporation by gas chromatography-mass spectrometry
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TLDR
Relative rates of O 18 incorporation have been measured for the acid catalyzed exchange reaction between H 2 O 18 and steroidal ketones, and represents an example of the considerable utility of mass spectrometry in obtaining kinetic data.About:
This article is published in Steroids.The article was published on 1969-11-01. It has received 28 citations till now. The article focuses on the topics: Mass spectrometry.read more
Citations
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Journal ArticleDOI
Novel pathways of bile acid metabolism involving CYP3A4.
TL;DR: It is demonstrated that CYP3A4 can metabolise lithocholic acid into 3-dehydrolithocholics acid, a potent activator of the nuclear receptors, pregnane X receptor and 1,25-dihydroxy vitamin D3 receptor, which are known to regulate the expression of CYP 3A4, and provides a feed-forward metabolism of toxic bile acid that may be of importance in maintaining bile acids homeostasis.
Journal ArticleDOI
Preferential utilization of newly synthesized cholesterol as substrate for bile acid biosynthesis. An in vivo study using 18O2-inhalation technique.
Ingemar Björkhem,A Lewenhaupt +1 more
TL;DR: It was calculated that at least 50% of the biosynthesized bile acids were derived from newly synthesized cholesterol, indicating that a small part of chenodeoxycholic acid might have been synthesized from a pool of cholesterol different from that utilized in the biosynthesis of cholic acid.
Book ChapterDOI
Newer approaches to the isolation, identification, and quantitation of steroids in biological materials.
Jan Sjövall,Magnus Axelson +1 more
TL;DR: This chapter discusses the newer approaches to the isolation, identification, and quantitation of steroids in biological materials, and the successful combination of gas chromatography and mass spectrometry (GC-MS) for analysis of molecules as large as steroids.
Book ChapterDOI
Preparation of labeled molecules by exchange with oxygen-18 water.
Robert C. Murphy,Keith L. Clay +1 more
TL;DR: This chapter discusses the synthesis of 18 O-labeled molecules to equilibrium exchange reactions with H 2 18 0, which has been a powerful means to address numerous problems in chemistry and biochemistry which had been difficult or impossible to probe by other techniques.
References
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Journal ArticleDOI
Use of a Mass Spectrometer as a Detector and Analyzer for Effluent Emerging from High Temperature Gas Liquid Chromatography Columns.
Book ChapterDOI
The Reversible Hydration of Carbonyl Compounds
TL;DR: In this paper, the reversible hydration of carbonyl compounds is discussed, and the equilibrium constants of the hydration equilibrium constants are discussed, as well as the experimental methods and results relevant to acidity of hydrates.
Journal ArticleDOI
Oxygen-18 Exchange Reactions of Aldehydes and Ketones
Marianne Byrn,Melvin Calvin +1 more
TL;DR: Using infra-red spectroscopy, the equilibrium exchange times have been determined for a series of ketones, aromatic aldehydes, and {beta}-ketoesters reacting with oxygen 18 enriched water as mentioned in this paper.
Journal ArticleDOI
The Role of Non-bonded Repulsions in Secondary Isotope Effects. I. Alpha and Beta Substitution Effects.1
TL;DR: In this article, the non-bonded model is extended to the treatment of isotope effects, and the alpha deuterium isotope effect, previously regarded as unrelated to the beta effect, is found to be accounted for semi-quantitatively by the same model.
Journal ArticleDOI
Combination gas chromatography-mass spectrometry
TL;DR: The direct combination of gas-liquid chromatography with mass spectrometry represents one of the most powerful techniques available for the analysis of complex mixtures of lipids as discussed by the authors, and the combination instrument may frequently prove highly useful for following chemical reactions in the preparation of new types of derivatives for GLC.
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