Testosterone deuterium labeled

This latter product may arise via direct hydrogen abstraction or via a single-electron oxidation of the radical to the cation followed by elimination of a proton. Results of CYP17A catalyzed oxidation of substrates bearing deuterium labels at the Cl6, Cl7 and the methyl group a to the ketone are in agreement with this mechanism . The 17-0-acetyl-testosterone is probably best explained as... 

Differentiation Between Endogenous and Exogenous Testosterone in Human Plasma and Urine After Oral Administration of Deuterium-Labeled Testosterone by Mass Fragmentography J. Clin. Endocrinol. Metab. 50(5) 889-894 (1980) CA 93 21970b... 

A separation in the metabolic route occurs on the reduction of the double bond of A -androstene-3,17-dione (LV), affording two saturated diketones isomeric at Cs. These are rings A/B trans, androstane-3,17-dione (LX), and rings A/B cis, etiocholane-3,17-dione (LXI). Both of these diketones have been isolated from urine. " That these two diketones are true metabolites of testosterone has been shown by the isolation of the tagged substances after injection of deuterium-labeled hormone. Once the metabolic course has diverged upon the reduction of the a, unsaturated ketone to the isomeric diketones, there is no crossing over from one branch of the pathway to the other. Thus, after the administration of either deuterium-labeled or nonisotopic androstane-3,17-dione (LX), only... 

The application of the twin ion technique [257] is also of importance in metabolism studies. The doubly labelled steroids [4- C+ 7-l- Ho.44]-androstenedione and [4- C + 7/3- Ho.42]-testosterone, were incubated with human placental microsomes and the resulting metabolites quantitated by counting C and identified by GC-MS [258]. The identified metabolites 17/8,19-dihydroxyandrost-4-en-3-one, 19-hydroxyandrost-4-en-3,17-dione, 17/8-hydroxy-3-oxo-androst-4-en-3-one, 3,17-dioxoandrost-4-en-19-al, oestradiol-17/3 and oestrone were easily recognisable from the double sets of relevant ions in their spectra due to the mixture of hydrogen and deuterium substitution at C-7. Hence the presence of the aromatizing enzymes in the placental preparation and the intermediates in oestrogen biosynthesis were confirmed. 

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