Steroid: Difference between revisions
imported>David E. Volk No edit summary |
imported>David E. Volk (cholesterol image with nomenclature) |
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[[Image:Cholesterol structure nomenclature DEVolk.jpg|right|thumb|350px|{{#ifexist:Template:Cholesterol structure nomenclature DEVolk.jpg/credit|{{Cholesterol structure nomenclature DEVolk.jpg/credit}}<br/>|}}Structure and nomenclature of cholesterol. All other steroids nomenclature is based on cholesterol. By convention, substituents pointing up, like C-18 and C-19 are called <math>\beta</math> while those pointing down are called <math>\alpha</math>.]] | |||
'''Steroids''', or '''steroid hormones''' are powerful hormones with drastic effects, both good and bad, when artificially introduced into living systems. Athletes have often taken anobolic steroids to improve muscle growth and athletic performance. Glucocorticoids play a role in inflamation, and estrogens have been linked to cancer. Testosterone and estrogen influence sexual traits (maleness/femaleness). All steroid hormones are naturally synthesized from cholesterol. The five major classes of steroids are: [[progestagens]], [[glucocorticoids]], [[mineralcorticoids]], [[androgens]] and [[estrogens]]. The steroid hormones activate gene expression by binding to enhancer proteins, called [[steroid receptors]]. | '''Steroids''', or '''steroid hormones''' are powerful hormones with drastic effects, both good and bad, when artificially introduced into living systems. Athletes have often taken anobolic steroids to improve muscle growth and athletic performance. Glucocorticoids play a role in inflamation, and estrogens have been linked to cancer. Testosterone and estrogen influence sexual traits (maleness/femaleness). All steroid hormones are naturally synthesized from cholesterol. The five major classes of steroids are: [[progestagens]], [[glucocorticoids]], [[mineralcorticoids]], [[androgens]] and [[estrogens]]. The steroid hormones activate gene expression by binding to enhancer proteins, called [[steroid receptors]]. | ||
== cholesterol (C27) == | == cholesterol (C27) == | ||
Cholesterol is the prototypical steroid hormone from which all others are synthesized. Because of this, all steroid numbering and nomenclature follow that of cholesterol. Some cholesterol derivatives have a proton added to the C-5 carbon. If the H-5 proton is alpha-oriented (points down) then rings A and B are fused in a trans conformation, but in the beta orientation, the rings are fused in a cis conformation. All steroids with an H5 are in the 5<math>\alpha</math> | Cholesterol is the prototypical steroid hormone from which all others are synthesized. Because of this, all steroid numbering and nomenclature follow that of cholesterol. Some cholesterol derivatives have a proton added to the C-5 carbon. If the H-5 proton is alpha-oriented (points down) then rings A and B are fused in a trans conformation, but in the beta orientation, the rings are fused in a cis conformation. All steroids with an H5 are in the 5<math>\alpha</math> orientation, while bile salts derived from cholesterol have the 5<math>\beta</math> orientation. | ||
== pregnenolone (C21) == | == pregnenolone (C21) == | ||
Revision as of 19:11, 20 December 2007
Steroids, or steroid hormones are powerful hormones with drastic effects, both good and bad, when artificially introduced into living systems. Athletes have often taken anobolic steroids to improve muscle growth and athletic performance. Glucocorticoids play a role in inflamation, and estrogens have been linked to cancer. Testosterone and estrogen influence sexual traits (maleness/femaleness). All steroid hormones are naturally synthesized from cholesterol. The five major classes of steroids are: progestagens, glucocorticoids, mineralcorticoids, androgens and estrogens. The steroid hormones activate gene expression by binding to enhancer proteins, called steroid receptors.
cholesterol (C27)
Cholesterol is the prototypical steroid hormone from which all others are synthesized. Because of this, all steroid numbering and nomenclature follow that of cholesterol. Some cholesterol derivatives have a proton added to the C-5 carbon. If the H-5 proton is alpha-oriented (points down) then rings A and B are fused in a trans conformation, but in the beta orientation, the rings are fused in a cis conformation. All steroids with an H5 are in the 5 orientation, while bile salts derived from cholesterol have the 5 orientation.