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5α-pregnan-17α-ol-3,20-dione
5α-Pregnan-17α-ol-3,20-dione, also known as 17α-hydroxy-dihydroprogesterone (17‐OH-DHP) is an endogenous steroid. Function 5α-Pregnan-17α-ol-3,20-dione is the first intermediate product within the androgen backdoor pathway in which 17α-hydroxyprogesterone (17‐OHP) is 5α-reduced and finally converted to 5α-dihydrotestosterone (DHT) without testosterone intermediate. The subsequent intermediate products in the pathway are 5α-pregnane-3α,17α-diol-20-one, androsterone and 5α-androstane-3α,17β-diol. Biosynthesis 5α-Pregnan-17α-ol-3,20-dione is produced by 5α-reduction of 17-OHP. The reaction is catalyzed by SRD5A1/SRD5A2 enzymes. See also * Androgen backdoor pathway * 5α-Dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including ... References {{End ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5α-Pregnane-3α,17α-diol-20-one
5α-Pregnane-3α,17α-diol-20-one, also known as 17α-hydroxyallopregnanolone (17-OH-allo) is an endogenous steroid. Function 5α-Pregnane-3α,17α-diol-20-one is an intermediate product within the androgen backdoor pathway in which 17α-hydroxyprogesterone (17‐OHP) is 5α-reduced and finally converted to 5α-dihydrotestosterone (DHT) without testosterone as a metabolic intermediate. The pathway can be outlined as 17-OHP → 5α-pregnan-17α-ol-3,20-dione → 5α-pregnane-3α,17α-diol-20-one → androsterone → 5α-androstane-3α,17β-diol → DHT. Biosynthesis 5α-Pregnane-3α,17α-diol-20-one is produced from 5α-pregnan-17α-ol-3,20-dione in a reaction catalyzed by a reductive 3α-hydroxysteroid dehydrogenase (3α-HSD), i.e. by the two aldo-keto reductase isozymes: AKR1C2 and AKR1C4, and by 17β-hydroxysteroid dehydrogenase 6 (HSD17B6) that also has the 3α-HSD activity. See also * Androgen backdoor pathway * Pregnane * 5α-Pregnane * Allopregnane * Allopregnanolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androgen Backdoor Pathway
The androgen backdoor pathway is a collective name for all metabolic pathways where clinically relevant androgens are synthesized with roundabout of testosterone as an intermediate product. Initially described as pathway where 5α-reduction of 17α-hydroxyprogesterone ultimately leads to 5α-dihydrotestosterone, several other pathways have been since then discovered that lead to 11-oxyandrogens which are potent agonists of the androgen receptors. A backdoor pathway is an alternative to the conventional, canonical androgenic pathway that involves testosterone. Dihydrotestosterone The primary feature of the androgen backdoor pathway is that 17α-hydroxyprogesterone (17-OHP) can be 5α-reduced and finally converted to 5α-dihydrotestosterone (DHT) via an alternative route that bypasses the conventional intermediates androstenedione and testosterone. In mammals, this route is activated during normal prenatal development and leads to early male sexual differentiation. It was first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androgen Backdoor Pathway
The androgen backdoor pathway is a collective name for all metabolic pathways where clinically relevant androgens are synthesized with roundabout of testosterone as an intermediate product. Initially described as pathway where 5α-reduction of 17α-hydroxyprogesterone ultimately leads to 5α-dihydrotestosterone, several other pathways have been since then discovered that lead to 11-oxyandrogens which are potent agonists of the androgen receptors. A backdoor pathway is an alternative to the conventional, canonical androgenic pathway that involves testosterone. Dihydrotestosterone The primary feature of the androgen backdoor pathway is that 17α-hydroxyprogesterone (17-OHP) can be 5α-reduced and finally converted to 5α-dihydrotestosterone (DHT) via an alternative route that bypasses the conventional intermediates androstenedione and testosterone. In mammals, this route is activated during normal prenatal development and leads to early male sexual differentiation. It was first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5α-dihydrotestosterone
Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver, and brain. This enzyme mediates reduction of the C4-5 double bond of testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor (AR). In addition to its role as a natural hormone, DHT has been used as a medication, for instance in the treatment of low testosterone levels in men; for information on DHT as a medication, see the androstanolone article. Biological function DHT is biologically important for sexual differentiation of the male genitalia during embryogenesis, maturation of the penis and scrotum at puberty, growth of facial, body, and pubic hair, and development and maintenance of the prostate gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5α-Dihydrotestosterone
Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver, and brain. This enzyme mediates reduction of the C4-5 double bond of testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor (AR). In addition to its role as a natural hormone, DHT has been used as a medication, for instance in the treatment of low testosterone levels in men; for information on DHT as a medication, see the androstanolone article. Biological function DHT is biologically important for sexual differentiation of the male genitalia during embryogenesis, maturation of the penis and scrotum at puberty, growth of facial, body, and pubic hair, and development and maintenance of the prostate gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endogenous
Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, estradiol is an endogenous estrogen hormone produced within the body, whereas ethinylestradiol Ethinylestradiol (EE) is an estrogen medication which is used widely in birth control pills in combination with progestins. In the past, EE was widely used for various indications such as the treatment of menopausal symptoms, gynecological disord ... is an exogenous synthetic estrogen, commonly used in birth control pills. References External links *{{Wiktionary-inline, endogeny Biology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroid
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and as signaling molecules. Hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol (opisthokonts) or cycloartenol (plants). Lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene. The steroid core structure is typically composed of seventeen carbon atoms, bonded in four " fused" rings: three six-member cyclohexane rings (rings A, B and C in the first illustration) and one five-member cyclopentane ring (the D ring). Steroids vary by the functional groups attached to this four-ring core and by the oxidation state of the rings. Sterols are forms of steroids with a hydroxy group at position three and a skeleton derived from cholestane. ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
17α-hydroxyprogesterone
17α-Hydroxyprogesterone (17α-OHP), also known as 17-OH progesterone (17-OHP), or hydroxyprogesterone (OHP), is an endogenous progestogen steroid hormone related to progesterone. It is also a chemical intermediate in the biosynthesis of many other endogenous steroids, including androgens, estrogens, glucocorticoids, and mineralocorticoids, as well as neurosteroids. Biological activity 17α-OHP is an agonist of the progesterone receptor (PR) similarly to progesterone, albeit weakly in comparison. In addition, it is an antagonist of the mineralocorticoid receptor (MR) as well as a partial agonist of the glucocorticoid receptor (GR), albeit with very low potency ( EC50 >100-fold less relative to cortisol) at the latter site, also similarly to progesterone. Biochemistry Biosynthesis 17α-OHP is derived from progesterone via 17α-hydroxylase (encoded by CYP17A1) 17α-OHP increases in the third trimester of pregnancy primarily due to fetal adrenal production. This steroid is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5α-reductase
5α-Reductases, also known as 3-oxo-5α-steroid 4-dehydrogenases, are enzymes involved in steroid metabolism. They participate in three metabolic pathways: bile acid biosynthesis, androgen and estrogen metabolism. There are three isozymes of 5α-reductase encoded by the genes SRD5A1, SRD5A2, and SRD5A3. 5α-Reductases catalyze the following generalized chemical reaction: :a 3-oxo-5α-steroid + acceptor a 3-oxo-Δ4-steroid + reduced acceptor Where a 3-oxo-5α-steroid and acceptor are substrates, and a corresponding 3-oxo-Δ4-steroid and the reduced acceptor are products. An instance of this generalized reaction that 5α-reductase type 2 catalyzes is: :dihydrotestosterone + NADP+ \rightleftharpoons testosterone + NADPH + H+ where dihydrotestosterone is the 3-oxo-5α-steroid, NADP+ is the acceptor and testosterone is the 3-oxo-Δ4-steroid and NADPH the reduced acceptor. Production and activity The enzyme is produced in many tissues in both males and females, in the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testosterone
Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of androgenic hair, body hair. In addition, testosterone in both sexes is involved in health and well-being, including moods, behaviour, and in the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss. Testosterone is a steroid from the androstane class containing a ketone and a hydroxyl group at positions three and seventeen respectively. It is Biosynthesis, biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites. It exerts its action through binding to and activation of the androgen receptor. In humans and most other vertebrates, testost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolic Intermediate
Metabolic intermediates are molecules that are the precursors or metabolites of biologically significant molecules. Although these intermediates are of relatively minor direct importance to cellular function, they can play important roles in the allosteric regulation of enzymes. Clinical significance Some can be useful in measuring rates of metabolic processes (for example, 3,4-dihydroxyphenylacetic acid or 3-aminoisobutyrate). Because they can represent unnatural points of entry into natural metabolic pathways, some (such as AICA ribonucleotide) are of interest to researchers in developing new therapies. See also * Metabolism Metabolism {{chem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Androsterone
Androsterone, or 3α-hydroxy-5α-androstan-17-one, is an endogenous steroid hormone, neurosteroid, and putative pheromone. It is a weak androgen with a potency that is approximately 1/7 that of testosterone. Androsterone is a metabolite of testosterone and dihydrotestosterone (DHT). In addition, it can be converted back into DHT via 3α-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase, bypassing conventional intermediates such as androstanedione and testosterone, and as such, can be considered to be a metabolic intermediate in its own right. Androsterone is also known to be an inhibitory androstane neurosteroid, acting as a positive allosteric modulator of the GABAA receptor, and possesses anticonvulsant effects. The unnatural enantiomer of androsterone is more potent as a positive allosteric modulator of GABAA receptors and as an anticonvulsant than the natural form. Androsterone's 3β-isomer is epiandrosterone, and its 5β-epimer is etiocholanolone. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
