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Definition
 
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Abortifacient Agents, Steroidal definition: Steroidal compounds with abortifacient activity.
Anabolic Steroid definition: Synthetic derivatives of the male hormone, androgen, that promote tissue growth by increasing the metabolic processes involved with protein synthesis and are used to promote weight gain in wasting diseases. They are used by bodybuilders and athletes to increase muscle mass, strength, and stamina.
Cholesterol Side-Chain Cleavage Enzyme definition: A mitochondrial cytochrome P450 enzyme that catalyzes the side-chain cleavage of C27 cholesterol to C21 pregnenolone in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP11A1 gene, catalyzes the breakage between C20 and C22 which is the initial and rate-limiting step in the biosynthesis of various gonadal and adrenal steroid hormones.
Cytochrome P450C11A1 definition: Encoded by human CYP11A1 Gene (Cytochrome P450 Family), 521-aa 60-kDa (precursor) Cytochrome P450C11A1 is a mitochondrial inner membrane P450 heme-thiolate monooxygenase that catalyzes a side-chain cleavage reaction conversion of cholesterol to pregnenolone, the first (rate-limiting) step in the synthesis of steroid hormones. CYP11A1 defects cause congenital adrenal insufficiency (CAI) and congenital lipoid adrenal hyperplasia (CLAH). P450 enzymes catalyze reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. (NCI)
Pregnanes definition: Saturated derivatives of the steroid pregnane. The 5-beta series includes PROGESTERONE and related hormones; the 5-alpha series includes forms generally excreted in the urine.
pregnane compound definition: saturated derivatives of the steroid pregnane.
Receptors, Steroid definition: Proteins found usually in the cytoplasm or nucleus that specifically bind steroid hormones and trigger changes influencing the behavior of cells. The steroid receptor-steroid hormone complex regulates the transcription of specific genes.
Steroid 11-beta-Hydroxylase definition: A mitochondrial cytochrome P450 enzyme that catalyzes the 11-beta-hydroxylation of steroids in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP11B1 gene, is important in the synthesis of CORTICOSTERONE and HYDROCORTISONE. Defects in CYP11B1 cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL).
Cytochrome P450 CYP11B1 definition: Encoded by human CYP11B1 Gene (Cytochrome P450 Family), 503-aa 58-kDa (precursor) Cytochrome P450 CYP11B1 is a mitochondrial inner membrane P450 heme-thiolate monooxygenase expressed in adrenal cortex with steroid 11-beta-hydroxylase activity and involved in conversion of progesterone to cortisol. The 18 or 19-hydroxylation of steroids and aromatization of androstendione to estrone have also been ascribed to CYP11B1. CYP11B1 defects cause adrenal hyperplasia type IV (AH-IV). CYP11B1/CYP11B2 gene fusion causes glucocorticoid-remediable aldosteronism (GRA). P450 enzymes catalyze reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. (NCI)
Steroid 17-alpha-Hydroxylase definition: A microsomal cytochrome P450 enzyme that catalyzes the 17-alpha-hydroxylation of progesterone or pregnenolone and subsequent cleavage of the residual two carbons at C17 in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP17 gene, generates precursors for glucocorticoid, androgen, and estrogen synthesis. Defects in CYP17 gene cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL) and abnormal sexual differentiation.
Cytochrome P450 XVIIA1 definition: Encoded by human CYP17A1 Gene (Cytochrome P450 Family), 508-aa 57-kDa Cytochrome P450 XVIIA1 is a cAMP-regulated endoplasmic reticulum P450 heme-thiolate monooxygenase with 17alpha-hydroxylase and 17,20-lyase activity and a key enzyme in the steroidogenic pathway that produces progestins, mineralocorticoids, glucocorticoids, androgens, and estrogens. Involved in fetal and adult sexual development, CYP17A1 converts pregnenolone and progesterone to their 17-alpha-hydroxylated products and subsequently to dehydroepiandrosterone (DHEA) and androstenedione. CYP17A1 mutations are associated with steroid-17 alpha-hydroxylase deficiency, 17-alpha-hydroxylase/17,20-lyase deficiency, pseudohermaphroditism, and adrenal hyperplasia type V (AH-V). P450 enzymes catalyze reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. (NCI)
Steroid 21-Hydroxylase definition: An adrenal microsomal cytochrome P450 enzyme that catalyzes the 21-hydroxylation of steroids in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP21 gene, converts progesterones to precursors of adrenal steroid hormones (CORTICOSTERONE; HYDROCORTISONE). Defects in CYP21 cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL).
Steroid Hydroxylases definition: Cytochrome P-450 monooxygenases (MIXED FUNCTION OXYGENASES) that are important in steroid biosynthesis and metabolism.
Steroid Isomerases definition: Enzymes that catalyze the transposition of double bond(s) in a steroid molecule. EC 5.3.3.
Steroid 12-alpha-Hydroxylase definition: A liver microsomal cytochrome P450 enzyme that catalyzes the 12-alpha-hydroxylation of a broad spectrum of sterols in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP8B1gene, converts 7-alpha-hydroxy-4-cholesten-3-one to 7-alpha-12-alpha-dihydroxy-4-cholesten-3-one and is required in the synthesis of BILE ACIDS from cholesterol.
Steroids definition: A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)
steroid definition: compounds that contain a hydrogenated cyclopentanoperhydrophenanthrene ring system; they include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols, and certain natural drugs and poisons.
steroid definition: (STAIR-oyd) A type of drug used to relieve swelling and inflammation.
Steroid Compound definition: Steroids are compounds possessing the skeleton of cyclopenta[a]phenanthrene or a skeleton derived therefrom by one or more bond scissions or ring expansions or contractions. Methyl groups are normally present at C-10 and C-13. An alkyl side chain may also be present at C-17. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons.
Steryl-Sulfatase Protein definition: Steryl-Sulfatase Protein (583 aa, 65 kDa) is a development protein that is encoded by the human STS gene and plays a role in steroid synthesis.
Steryl-Sulfatase definition: An arylsulfatase with high specificity towards sulfated steroids. Defects in this enzyme are the cause of ICHTHYOSIS, X-LINKED.
Cytochrome P-450 CYP27A1 definition: An NAPH-dependent cytochrome P450 enzyme that catalyzes the oxidation of the side chain of sterol intermediates such as the 27-hydroxylation of 5-beta-cholestane-3-alpha,7-alpha, 12-alpha-triol. Cytochrome P-450 CYP27A1 is a mitochondrial enzyme; however microsomal-derived homologs of the enzyme have been identified and are included under this heading.
Steroid 16-alpha-Hydroxylase definition: A liver microsomal cytochrome P450 enzyme that catalyzes the 16-alpha-hydroxylation of a broad spectrum of steroids, fatty acids, and xenobiotics in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme is encoded by a number of genes from several CYP2 subfamilies.
Aldosterone Synthase definition: A mitochondrial cytochrome P450 enzyme that catalyzes the 18-hydroxylation of steroids in the presence of molecular oxygen and NADPH-specific flavoprotein. This enzyme, encoded by CYP11B2 gene, is important in the conversion of CORTICOSTERONE to 18-hydroxycorticosterone and the subsequent conversion to ALDOSTERONE.
steroid therapy definition: Treatment with corticosteroid drugs to reduce swelling, pain, and other symptoms of inflammation.
steroid hormone definition: hormone characterized by the presence of a cyclopentanoperhydrophenanthrene ring, includes the estrogens, androgens, mineralocorticoids, progestogens, and glucocorticoids.
Steroid Hormone definition: Hormones possessing the steroid ring system; e.g., androgens, estrogens, adrenocortical hormones.
Therapeutic Steroid Hormone definition: Synthetically made hormones possessing the steroid ring system; e.g., androgens, estrogens, and adrenocortical hormones.
saponin definition: A substance found in soybeans and many other plants. Saponins may help lower cholesterol and may have anticancer effects.
steroid analog definition: synthetic or natural compound which resembles a naturally occurring steroid in structure and/or function.
steroid biosynthetic process definition: The chemical reactions and pathways resulting in the formation of steroids, compounds with a 1,2,cyclopentanoperhydrophenanthrene nucleus; includes de novo formation and steroid interconversion by modification. [GOC:go_curators]
steroid biosynthesis definition: anabolic formation of steroid compounds in organisms, living cells, or by subcellular fractions.
steroid metabolic process definition: The chemical reactions and pathways involving steroids, compounds with a 1,2,cyclopentanoperhydrophenanthrene nucleus. [ISBN:0198547684]
steroid metabolism definition: the buildup and breakdown of steroids for utilization by the organism; includes metabolism of cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols.
Steroid Metabolism definition: Steroid Metabolism consists of diverse biochemical reactions that convert steroid compounds, lipids containing a hydrogenated cyclopentanoperhydrophenanthrene ring system, to metabolic derivatives for assorted uses, such as steroid hormone production and biosynthesis of cell membrane constituents.
steroid 7alpha hydroxylase definition: nonEC.
steroid binding definition: Interacting selectively with a steroid, any of a large group of substances that have in common a ring system based on 1,2-cyclopentanoperhydrophenanthrene. [GOC:jl, ISBN:0198506732 "Oxford Dictionary of Biochemistry and Molecular Biology"]
11-beta-hydroxysteroid dehydrogenase activity definition: Catalysis of the reaction: an 11-beta-hydroxysteroid + NAD(P)+ = an 11-oxosteroid + NAD(P)H + H+. [EC:1.1.1.146, PMID:15761036]
3-oxo-5-alpha-steroid 4-dehydrogenase activity definition: Catalysis of the reaction: a 3-oxo-5-alpha-steroid + acceptor = a 3-oxo-delta(4)-steroid + reduced acceptor. [EC:1.3.99.5]
steroid catabolic process definition: The chemical reactions and pathways resulting in the breakdown of steroids, compounds with a 1,2,cyclopentanoperhydrophenanthrene nucleus. [GOC:go_curators]
Steroid Measurement definition: The determination of the amount of any steroid present in a sample.
12-alpha-hydroxysteroid dehydrogenase activity definition: Catalysis of the reaction: NADP+ + 3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholanate = NADPH + H+ + 3-alpha,7-alpha-dihydroxy-12-oxo-5-beta-cholanate. [EC:1.1.1.176, MetaCyc:1.1.1.176-RXN]
16-alpha-hydroxysteroid dehydrogenase activity definition: Catalysis of the reaction: NADP+ + 16-alpha-hydroxysteroid = NADPH + H+ + 16-oxosteroid. [EC:1.1.1.147, MetaCyc:1.1.1.147-RXN]
Steroid Lipomatosis definition: A neoplastic process characterized by a diffuse poorly circumscribed overgrowth of adipose tissue in the face, upper middle back, and sternal region. It is associated with adrenocortical steroid therapy or an increase in endogenous adrenocortical hormone.
CYP11B2 Gene definition: This gene is involved in mineralocorticoid metabolism.
STS Gene definition: This gene plays a role in synthesis of steroids during pregnancy.
Steroid Biochemistry definition: The metabolism of steroid compounds.
Cytochrome P450 XXIB definition: Encoded by human CYP21A2 Gene (Cytochrome P450 Family), 494-aa 56-kDa Cytochrome P450 XXIB is a membrane-bound endoplasmic reticulum P450 heme-thiolate monooxygenase that hydroxylates steroids at the 21 position and is required for synthesis of steroid hormones including cortisol and aldosterone. The leucine-rich hydrophobic N-terminal region may anchor the protein. CYP21A2 defects cause congenital adrenal hyperplasia (CAH). Gene conversion events involving CYP21A2 and a nearby pseudogene are thought to account for many cases of steroid 21-hydroxylase deficiency. P450 enzymes catalyze reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. (NCI)
Cytochrome P450 11B2 definition: Encoded by human CYP11B2 Gene (Cytochrome P450 Family), 503-aa 58-kDa (precursor) Cytochrome P450 11B2 is a mitochondrial inner membrane P450 heme-thiolate monooxygenase with steroid 18-hydroxylase activity involved in preferential conversion of 11-deoxycorticosterone to aldosterone and 18-oxocortisol via corticosterone and 18-hydroxycorticosterone. CYP11B2 also has steroid 11 beta-hydroxylase activity. CYP11B2 defects cause corticosterone methyloxidase type I deficiency (CMO-I deficiency) and corticosterone methyloxidase type II deficiency (CMO-II deficiency). CYP11B2/CYP11B1 gene fusion causes glucocorticoid-remediable aldosteronism (GRA). P450 enzymes catalyze reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. (NCI)
steroid acetylation definition: The addition of an acetyl group to a steroid molecule. An acetyl group is CH3CO-, derived from acetic [ethanoic] acid. [GOC:mah]
steroid deacetylation definition: The removal of an acetyl group from a steroid molecule. An acetyl group is CH3CO-, derived from acetic [ethanoic] acid. [GOC:mah]
Dietary Steroid definition: A chemically heterogeneous group of organic compounds found in food containing a 17-carbon 4-ring system (cyclopentanoperhydro-phenanthrene ring system).
steroid esterification definition: A lipid modification process in which a steroid ester is formed by the combination of a carboxylic acid (often a fatty acid) and a steroid molecule (e.g. cholesterol). [GOC:mah, GOC:pd, GOC:rl]
 
 
frFrench
anabolisant definition: Substance facilitant ou augmentant les phénomènes d'anabolisme c'est-à-dire de production tissulaire notamment de la masse musculaire.
stéroïde definition: Lipide dérivant de triterpénoïdes (lipides à 30 atomes de carbones), majoritairement le squalène, et se caractérisant par un noyau cyclopentanophénanthrénique hydrophobe partiellement ou totalement hydrogené.