Publications

• The in vitro metabolism of 11beta-hydroxyprogesterone and 11-ketoprogesterone to 11-ketodihydrotestosterone in the backdoor pathway.

  van Rooyen D., Gent R., Barnard L., Swart A.C.

  Increased circulating 11β-hydroxyprogesterone (11OHP4), biosynthesised in the human adrenal, is associated with 21-hydroxylase deficiency in congenital adrenal hyperplasia. 17α-hydroxyprogesterone levels are also increased, with the steroid's metabolism to dihydrotestosterone in the backdoor pathw ... >> More

  Increased circulating 11β-hydroxyprogesterone (11OHP4), biosynthesised in the human adrenal, is associated with 21-hydroxylase deficiency in congenital adrenal hyperplasia. 17α-hydroxyprogesterone levels are also increased, with the steroid's metabolism to dihydrotestosterone in the backdoor pathway contributing to hyperandrogenic clinical conditions. In this study we investigated the in vitro biosynthesis and downstream metabolism of 11OHP4. Both cytochrome P450 11β-hydroxylase and aldosterone synthase catalyse the biosynthesis of 11OHP4 from progesterone (P4) which is converted to 11-ketoprogesterone (11KP4) by 11β-hydroxysteroid dehydrogenase type 2, while type 1 readily catalysed the reverse reaction. We showed in HEK-293 cells that these C11-oxy C₂₁ steroids were metabolised by steroidogenic enzymes in the backdoor pathway-5α-reductase (SRD5A) and 3α-hydroxysteroid type 3 (AKR1C2) converted 11OHP4 to 5α-pregnan-11β-ol,3,20-dione and 5α-pregnan-3α,11β-diol-20-one, while 11KP4 was converted to 5α-pregnan-3,11,20-trione and 5α-pregnan-3α-ol-11,20-dione (alfaxalone), respectively. Cytochrome P450 17α-hydroxylase/17,20-lyase catalysed the hydroxylase and lyase reaction to produce the C11-oxy C₁₉ steroids demonstrated in the conversion of alfaxalone to 11-oxy steroids demonstrated in the conversion of alfaxalone to 11ketoandrosterone. In LNCaP cells, a prostate cancer cell model endogenously expressing the relevant enzymes, 11OHP4 and 11KP4 were metabolised to the potent androgen, 11-ketodihydrotestosterone (11KDHT), thus suggesting the C11-oxy C₂₁ steroids contribute to the pool of validating the in vitro biosynthesis of C11-oxy C₁₉ steroids from C11-oxy C₂₁ steroids. The in vitro reduction of 11KP4 at C3 and C5 by AKR1C2 and SRD5A has confirmed the metabolic route of the urinary metabolite, 3α,20α-dihydroxy-5β-pregnan-11-one. Although our assays have demonstrated the conversion of 11OHP4 and 11KP4 by steroidogenic enzymes in the backdoor pathway yielding 11KDHT, thus suggesting the C11-oxy C₂₁ steroids contribute to the pool of potent androgens, the in vivo confirmation of this metabolic route remains challenging. << Less

  J Steroid Biochem Mol Biol 178:203-212(2018) [PubMed] [EuropePMC]

  This publication is cited by 10 other entries.

• The 11beta-hydroxysteroid dehydrogenase isoforms: pivotal catalytic activities yield potent C11-oxy Cpisub>19pi/sub> steroids with 11betaHSD2 favouring 11-ketotestosterone, 11-ketoandrostenedione and 11-ketoprogesterone biosynthesis.

  Gent R., du Toit T., Bloem L.M., Swart A.C.

  The 11β-hydroxysteroid dehydrogenase (11βHSD) types 1 and 2 are primarily associated with glucocorticoid inactivation and reactivation. Several adrenal C11-oxy C₁₉ and C11-oxy C₂₁ steroids, which have been identified in prostate cancer, 21-hydroxylase deficiency and polycysti ... >> More

  The 11β-hydroxysteroid dehydrogenase (11βHSD) types 1 and 2 are primarily associated with glucocorticoid inactivation and reactivation. Several adrenal C11-oxy C₁₉ and C11-oxy C₂₁ steroids, which have been identified in prostate cancer, 21-hydroxylase deficiency and polycystic ovary syndrome, are substrates for these isozymes. This study describes the kinetic parameters of 11βHSD1 and 11βHSD2 towards the C11-keto and C11-hydroxy derivatives of the C₁₉ and C₂₁ steroids. The apparent K_m and V_max values indicate the more prominent 11βHSD2 activity towards 11β-hydroxy androstenedione, 11β-hydroxytestosterone and 11β-hydroxyprogesterone in contrast to the 11βHSD1 reduction of the C11-keto steroids, as was demonstrated in the LNCaP cell model in the production of 11-ketotestosterone and 11-ketodihydrotestosterone. Data highlighted the role of 11βHSD2 and cytochrome P450 17A1 in the contribution of C11-oxy C₂₁ steroids to the C11-oxy C₁₉ steroid pool in the C11-oxy backdoor pathway. In addition, 11βHSD2 activity, catalysing 11-ketotestosterone biosynthesis, was shown to be key in the production of prostate specific antigen and in the progression of prostate cancer to castration resistant prostate cancer. The study at hand thus provides evidence that 11βHSD isozymes play key roles in pathophysiological states, more so than was previously put forward. << Less

  J Steroid Biochem Mol Biol 189:116-126(2019) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.