80-92-2Relevant articles and documents
Substrate specificity and inhibitor sensitivity of rabbit 20α-hydroxysteroid dehydrogenase
Endo, Satoshi,Arai, Yuki,Hara, Akira,Kitade, Yukio,Bunai, Yasuo,El-Kabbani, Ossama,Matsunaga, Toshiyuki
, p. 1514 - 1518 (2013/10/08)
In this study, we examined the substrate specificity and inhibitor sensitivity of rabbit 20α-hydroxysteroid dehydrogenase (AKR1C5), which plays a role in the termination of pregnancy by progesterone inactivation. AKR1C5 moderately reduced the 3-keto group of only 5α-dihydrosteroids with 17β- or 20α/β-hydroxy group among 3-ketosteroids. In contrast, the enzyme reversibly and efficiently catalyzed the reduction of various 17- and 20-ketosteroids, including estrogen precursors (dehydroepiandrosterone, estrone and 5α-androstan-3β- ol-17-one) and tocolytic 5β-pregnane-3,20- dione. In addition to the progesterone inactivation, the formation of estrogens and metabolism of the tocolytic steroid by AKR1C5 may be related to its role in rabbit parturition. AKR1C5 also reduced various non-steroidal carbonyl compounds, including isatin, an antagonist of the C-type natriuretic peptide receptor, and 4-oxo-2-nonenal, suggesting its roles in controlling the bioactive isatin and detoxification of cytotoxic aldehydes. AKR1C5 was potently and competitively inhibited by flavonoids such as kaempferol and quercetin, suggesting that its activity is affected by ingested flavonoids.
Stereospecific reduction of 5β-reduced steroids by human ketosteroid reductases of the AKR (aldo-keto reductase) superfamily: Role of AKR1C1-AKR1C4 in the metabolism of testosterone and progesterone via the 5β-reductase pathway
Jin, Yi,Mesaros, A. Clementina,Blair, Ian A.,Penning, Trevor M.
supporting information; experimental part, p. 53 - 61 (2012/06/15)
Active sex hormones such as testosterone and progesterone are metabolized to tetrahydrosteroids in the liver to terminate hormone action. One main metabolic pathway, the 5β-pathway, involves 5β-steroid reductase (AKR1D1, where AKR refers to the aldo-keto reductase superfamily), which catalyses the reduction of the 4-ene structure, and ketosteroid reductases (AKR1C1-AKR1C4), which catalyse the subsequent reduction of the 3-oxo group. The activities of the four human AKR1C enzymes on 5β-dihydrotestosterone, 5β-pregnane-3,20-dione and 20α-hydroxy-5β-pregnan-3-one, the intermediate 5β-dihydrosteroids on the 5β-pathway of testosterone and progesterone metabolism, were investigated. Product characterization by liquid chromatography-MS revealed that the reduction of the 3-oxo group of the three steroids predominantly favoured the formation of the corresponding 3α-hydroxy steroids. The stereochemistry was explained by molecular docking. Kinetic properties of the enzymes identified AKR1C4 as the major enzyme responsible for the hepatic formation of 5β-tetrahydrosteroid of testosterone, but indicated differential routes and roles of human AKR1C for the hepatic formation of 5β-tetrahydrosteroids of progesterone. Comparison of the kinetics of the AKR1C1-AKR1C4-catalysed reactions with those of AKR1D1 suggested that the three intermediate 5β-dihydrosteroids derived from testosterone and progesterone are unlikely to accumulate in liver, and that the identities and levels of 5β-reduced metabolites formed in peripheral tissues will be governed by the local expression of AKR1D1 and AKR1C1-AKR1C3. The Authors Journal compilation 2011 Biochemical Society.
Borane Reduction of the Steroid 20-Ketone Group in the Presence of Various Chiral β-Amino Alcohols
Goendoes, Gyoergy,Orr, James C.
, p. 581 - 582 (2007/10/02)
The direction of reduction of 20-carbonyl group of 3α-hydroxy-5β-pregnan-20-one (1) with a complex of borane-methyl sulfide and chiral β-amino alcohols, depends on the chirality of the amino alcohol.Where there is a 2-phenyl or 2-benzyl substituent, then the S enantiomer gives exclusively the steroid 20R alcohol 3.The R enantiomer of 2-amino-2-phenyl-1-ethanol gives the highest steroid 20S (2) : 20R (3) alcohol ratio. Key Words: 5β-Pregnane, 3α-hydroxy-20-one / Chiral borane reduction / Borane reduction / Steroids
