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The hydroxylation at C-2 of testosterone and 5alpha-dihydrotestosterone is measured by isolation of HTO after incubating "metabolically labile" tritium labeled steroids with the enzymes. After hydroxylation of testosterone in rat liver 2alpha-hydroxytestosterone was isolated and identified by gaschromatography and mass spectra.
After incubation of testosterone with 105000g microsomes of human foetal liver, 6alpha-hydroxytestosterone was isolated and identified by t.l.c. and g.l.c.-mass spectrometry. This is the first example of 6alpha-hydroxylation of C(19) steroids in the human liver, and the finding is discussed in relation to earlier reports of 6-oxygenated C(19) and C(18) steroids in pregnant women.
Several cytochrome P-450 enzymes are able to hydroxylate testosterone to many different metabolites, some of which remain to be identified. One hitherto unidentified metabolite represents a major metabolite of P-450 2A2, present in the liver of adult male rats, and a minor metabolite of several other cytochrome P-450 enzymes. Using the techniques of HPLC and GC/MS, we have obtained unequivocal evidence that this metabolite is 12 alpha-hydroxytestosterone.
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A method is described for the preparation of two types of multi-labeled 6 beta-hydroxycortisol containing either five deuterium atoms at C-19 methyl and C-1 methylene or four 13C atoms at C-1, C-2, C-4, and C-19 in addition to the five deuterium atoms for use as analytical internal standards for gas chromatography-mass spectrometry (GC-MS). BMD derivatives of [1,1,19,19,19-2H(5)]cortisone and [1,2,4,19-13C(4),1,1,19,19,19-2H(5)]cortisone (cortisone-2H(5)-BMD and cortisone-13C(4),2H(5)-BMD) were first synthesized via indan synthon method starting from optical active 11-oxoindanylpropionic acid and labeled isopropenyl anion ([1,1,3,3,3-2H(5)]- or [1,3-13C(2),1,1,3,3,3-2H(5)]isopropenyl anion). The labeled isopropenyl anion was prepared from commercially available [1,1,1,3,3,3-2H(6)]- or [1,3-13C(2),1,1,1,3,3,3-2H(6)]acetone. Ultraviolet (UV) irradiated autoxidation at C-6 position of 3-ethyl-3,5-dienol ether derivatives of the labeled cortisone-BMDs gave 6 beta-hydroxy-[1,1,19,19,19-2H(5)]cortisone-BMD and 6 beta-hydroxy-[1,2,4,19-13C(4),1,1,19,19,19-2H(5)]cortisone-BMD, respectively, as a mixture of 6 beta- and 6 alpha-epimers in a ratio of 4:1. Separation of 6 beta- and 6 alpha-epimers by thin-layer chromatography (TLC) and subsequent hydrolysis of the BMD group at C-17 gave pure labeled 6 beta-hydroxycortisone. After protecting the keto group at C-3 of the labeled 6 beta-hydroxycortisone-BMD as semicarbazone, reduction of 11-keto group with NaBH(4) and subsequent removal of the C-3 and C-17 protecting groups gave 6beta-hydroxy-[1,1,19,19,19-2H(5)]cortisol (6 beta-hydroxycortisol-2H(5)) and 6 beta-hydroxy-[1,2,4,19-13C(4),1,1,19,19,19-2H(5)]cortisol (6 beta-hydroxycortisol-13C(4),2H(5)), respectively, as a mixture of 6 beta- and 6 alpha-epimers (6 beta:6 alpha=4.4:1). The isotopic compositions of 6 beta-hydroxycortisol-2H(5) and 6 beta-hydroxycortisol-13C(4),2H(5) were 90.9 and 92.1 at.%, respectively. Furthermore, 6 beta-hydroxy-[1 alpha,16,16,17 alpha-2H(4)]testosterone was synthesized by the UV irradiated autoxidation at C-6 position of 3-ethyl-3,5-dienol ether derivative of deuterium-labeled testosterone ([1 alpha,16,16,17 alpha-2H(4)]testosterone) obtained by using catalytic deuteration and hydrogen-deuterium exchange reactions.
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Homogenates of normal or cryptorchid, human testes were incubated with [3H]testosterone and a NADPH-generating system. [3H]4-andostene,7 alpha,17 beta-diol-3-one (7 alpha-OH-testosterone) was isolated and identified from such incubations. To our knowledge this is the first demonstration that 7 alpha-OH-testosterone is a metabolite of testosterone in the human testis. 4-Andro-stene,6 beta,17 beta-diol-3-one (6 beta-OH-testosterone) and 4-androstene,16 alpha,17 beta-diol-3-one (16 alpha-OH-testosterone) were also identified as testosterone metabolites. The specific activity of both testosterone 6 beta- and 16 alpha-hydroxylase was higher than that of 7 alpha-hydroxylase. Pre-pubertal or cryptorchid human testis tissues seem in our study to have higher testosterone 6 beta- and 7 alpha-hydroxylase activity than normal adult testis tissue.
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