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Steroid 11β-hydroxylase
Steroid 11β-hydroxylase, also known as steroid 11β-monooxygenase, is a steroid hydroxylase found in the zona glomerulosa and zona fasciculata of the adrenal cortex. Named officially the cytochrome P450 11B1, mitochondrial, it is a protein that in humans is encoded by the ''CYP11B1'' gene. The enzyme is involved in the biosynthesis of Adrenal gland, adrenal corticosteroids by catalyzing the addition of hydroxyl groups during oxidation reactions. Gene The ''CYP11B1'' gene encodes 11β-hydroxylase, a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. The product of this CYP11B1 gene is the 11β-hydroxylase protein. This protein localizes to the mitochondrial inner membrane and is involved in the conversion of various steroids in the adrenal cortex. Transcript variants encoding different isoforms have been noted for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroid Hydroxylase
A steroid hydroxylase is a class of hydroxylase enzymes involved in the biosynthesis of steroids. See also * Steroidogenic enzyme Additional images File:Steroidogenesis.svg, Steroidogenesis Image:Steroid numbering.svg, Steroid nomenclature — numbering of carbons Image:DHEA1.svg, Production of DHEA from Cholesterol References External links * EC 1.14 Steroids {{1.14-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroidogenic Enzyme
__NOTOC__ Steroidogenic enzymes are enzymes that are involved in steroidogenesis and steroid biosynthesis. They are responsible for the biosynthesis of the steroid hormones, including sex steroids (androgens, estrogens, and progestogens) and corticosteroids (glucocorticoids and mineralocorticoids), as well as neurosteroids, from cholesterol. Steroidogenic enzymes are most highly expressed in classical steroidogenic tissues, such as the testis, ovary, and adrenal cortex, but are also present in other tissues in the body. List of steroidogenic enzymes * Steroid desmolases ** Cholesterol side-chain cleavage enzyme (20,22-desmolase) – steroid synthesis ** 17,20-Lyase (17,20-desmolase) – androgen synthesis * Steroid hydroxylases ** 11β-Hydroxylase – corticosteroid synthesis ** 17α-Hydroxylase – androgen and glucocorticoid synthesis ** 18-Hydroxylase (aldosterone synthase) – mineralocorticoid synthesis ** 21-Hydroxylase – corticosteroid synthesis ** Cytochrom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
11β-hydroxyprogesterone
11β-Hydroxyprogesterone (11β-OHP), also known as 21-deoxycorticosterone, as well as 11β-hydroxypregn-4-ene-3,20-dione, is a naturally occurring, endogenous steroid and derivative of progesterone. It is a potent mineralocorticoid. Syntheses of 11β-OHP from progesterone is catalyzed by the steroid 11β-hydroxylase (CYP11B1) enzyme, and, to a lesser extent, by the aldosterone synthase enzyme (CYP11B2). Function Along with its epimer 11α-hydroxyprogesterone (11α-OHP), 11β-OHP has been identified as a very potent competitive Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indi ... inhibitor of both isoforms ( 1 and 2) of 11β-hydroxysteroid dehydrogenase (11β-HSD). Outcome of 21-hydroxylase deficiency It has been known since 1987 that increased levels of 11β-OHP occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Progesterone
Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the major progestogen in the body. Progesterone has a variety of important functions in the body. It is also a crucial metabolic intermediate in the production of other endogenous steroids, including the sex hormones and the corticosteroids, and plays an important role in brain function as a neurosteroid. In addition to its role as a natural hormone, progesterone is also used as a medication, such as in combination with estrogen for contraception, to reduce the risk of Uterine cancer, uterine or cervical cancer, in hormone replacement therapy, and in feminizing hormone therapy. It was first prescribed in 1934. Biological activity Progesterone is the most important progestogen in the body. As a potent agonist of the progesterone receptor, nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticosterone
Corticosterone, also known as 17-deoxycortisol and 11β,21-dihydroxyprogesterone, is a 21-carbon steroid hormone of the corticosteroid type produced in the cortex of the adrenal glands. In the very rare case of congenital adrenal hyperplasia due to 17α-hydroxylase deficiency cortisol production is blocked. Roles In many species, including amphibians, reptiles, rodents and birds, corticosterone is a main glucocorticoid, involved in regulation of energy, immune reactions, and stress responses. However, in humans, cortisol is the primary glucocorticoid that is produced primarily in the zona fasciculata of the adrenal cortex. Corticosterone has only weak glucocorticoid and mineralocorticoid potencies in humans and is important mainly as an intermediate in the steroidogenic pathway from pregnenolone to aldosterone. Corticosterone is converted to aldosterone by aldosterone synthase, found only in the mitochondria of glomerulosa cells. Glomerulosa cells are found in the zon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortisol
Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal cortex in an adrenal gland. In other tissues, it is produced in lower quantities. By a Circadian rhythm, diurnal cycle, cortisol is released and increases in response to Stress (biology), stress and a low Blood sugar, blood-glucose concentration. It functions to increase blood sugar through gluconeogenesis, suppress the immune system, and aid in the metabolism of calories. It also decreases bone formation. These stated functions are carried out by cortisol binding to glucocorticoid or mineralocorticoid receptors inside a cell, which then bind to DNA to affect gene expression. Health effects Metabolic response Metabolism of glucose Cortisol plays a crucial role in regulating glucose metabolism and promotes gluconeogenesis (glucose synthes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
18-Hydroxycorticosterone
18-Hydroxycorticosterone is an endogenous steroid. It is a derivative of corticosterone. Function 18-Hydroxycorticosterone serves as an intermediate in the synthesis of aldosterone by the enzyme aldosterone synthase in the zona glomerulosa. It is also an intermediate in the biosynthesis of corticosterone. It spontaneously and reversibly converts to various less polar forms and derivatives, some of which serve as precursors to aldosterone or corticosterone. Specifically, 21-hydroxy-11,18-oxido-4-pregnene-3,20-dione (18-DAL) is hydroxylated to aldosterone in the presence of malate and NADP+ at pH 4.8, indicating that 18-DAL acts as a metabolic intermediate between 18-hydroxycorticosterone and aldosterone. Corticosterone is a mediate precursor in this biosynthesis pathway, with 18-hydroxycorticosterone serving as an intermediate between corticosterone and aldosterone. See also * 18-Hydroxycortisol * Aldosterone synthase Aldosterone synthase, also called steroid 18-hydroxylase, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiotensin II
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex to promote sodium retention by the kidneys. An oligopeptide, angiotensin is a hormone and a dipsogen. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver. Angiotensin was isolated in the late 1930s (first named "angiotonin" or "hypertensin", later renamed "angiotensin" as a consensus by the 2 groups that independently discovered it) and subsequently characterized and synthesized by groups at the Cleveland Clinic and Ciba laboratories. Precursor and types Angiotensinogen Angiotensinogen is an α-2-globulin synthesized in the liver and is a precursor for angiotensin, but has also been indicated as having many other roles not related to angiotensin peptides. It is a me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldosterone Synthase
Aldosterone synthase, also called steroid 18-hydroxylase, corticosterone 18-monooxygenase or P450C18, is a steroid hydroxylase cytochrome P450 enzyme involved in the biosynthesis of the mineralocorticoid aldosterone and other steroids. The enzyme catalyzes sequential hydroxylations of the steroid angular methyl group at C18 after initial 11β-hydroxylation (the enzyme has steroid 18-hydroxylase activity as well as steroid 11 beta-hydroxylase activity). It is encoded by the gene in humans. Aldosterone synthase is a protein which is only expressed in the zona glomerulosa of the adrenal cortex and is primarily regulated by the renin–angiotensin system. It is the sole enzyme capable of synthesizing aldosterone in humans and plays an important role in electrolyte balance and blood pressure. Genetics Aldosterone synthase is encoded on chromosome 8q22 by the ''CYP11B2'' gene. The gene contains 9 exons and spans roughly 7000 base pairs of DNA. ''CYP11B2'' is closely related with '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
