The Full Wiki

steroid: Wikis


Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Encyclopedia

recommended ring lettering (left) and atom numbering (right) of the steroid skeleton.[1][2]]]

. The total number of carbons (30) reflects its triterpenoid origin.]]

(IPP),dimethylallyl pyrophosphate (DMAPP), geranyl pyrophosphate (GPP) and squalene shown. Some intermediates are omitted.]]

A steroid is a terpenoid lipid characterized by a carbon skeleton with four fused rings, generally arranged in a 6-6-6-5 fashion. Steroids vary by the functional groups attached to these rings and the oxidation state of the rings. Hundreds of distinct steroids are found in plants, animals, and fungi. All steroids are made in cells either from the sterol lanosterol (animals and fungi) or from the sterol cycloartenol (plants). Both sterols are derived from the cyclization of the triterpene squalene.[3]

Contents

Origin

Steroids include estrogen, cortisol, progesterone, and testosterone. Estrogen and progesterone are made primarily in the ovary and in the placenta during pregnancy, and testosterone in the testes. Testosterone is also converted into estrogen to regulate the supply of each, in the bodies of both females and males. Certain neurons and glia in the central nervous system (CNS) express the enzymes that are required for the local synthesis of pregnane neurosteroids, either de novo or from peripherally-derived sources. The rate-limiting step of steroid synthesis is the conversion of cholesterol to pregnenolone, which occurs inside the mitochondrion.[4]

Classification

Taxonomical/Functional

Some of the common categories of steroids:

Structural

It is also possible to classify steroids based upon their chemical composition. One example of how MeSH performs this classification is available at the Wikipedia MeSH catalog. Examples from this classification include:

Class Examples Number of carbon atoms
Cholstanes cholesterol 27
Cholanes cholic acid 24
Pregnanes progesterone 21
Androstanes testosterone 19
Estranes estradiol 18

See also

References

  1. ^ "IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN). The nomenclature of steroids. Recommendations 1989". Eur. J. Biochem. 186 (3): 429–58. December 1989. doi:10.1111/j.1432-1033.1989.tb15228.x. PMID 2606099. http://www.chem.qmul.ac.uk/iupac/steroid/. 
  2. ^ G. P. Moss (1989). "Nomenclature of Steroids (Recommendations 1989)". Pure & Appl. Chem. 61 (10): 1783–1822. doi:10.1351/pac198961101783. 
  3. ^ Lanosterol biosynthesis
  4. ^ Rossier MF (2006). "T channels and steroid biosynthesis: in search of a link with mitochondria". Cell Calcium. 40 (2): 155–64. doi:10.1016/j.ceca.2006.04.020. PMID 16759697. 

External links


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

Contents

English

Wikipedia-logo.png
Wikipedia has an article on:

Wikipedia

Etymology

From sterol + -oid.

Pronunciation

Noun

Singular
steroid

Plural
steroids

steroid (plural steroids)

  1. (biochemistry) A class of organic compounds having a structure of 17 carbon atoms arranged in four rings; they are lipids, and occur naturally as sterols, bile acids, adrenal and sex hormones, and some vitamins; many drugs are synthetic steroids.
  2. (bodybuilding) Any anabolic hormone used to promote muscle growth.
  3. (sports, US) Any chemical compound used to enhance athletic performance.

Hyponyms

Translations

Anagrams


Simple English

A steroid is a drug that helps a person do better in areas such as sports, as well as give them more physical strength. Often, steroids are used to improve a person's performance, but they are sometimes overused and abused by athletes that depend on steroids. The rate of steroid abuse has grown by a high percentage in the last few years, and people all over the world continue to use them. Steroids can have very bad effects on the human body . The substances that are steroids for vertebrates are either hormones, or cholesterol. Steroids can kill people, and they have many side effects for both men and women. They are common in sports, but also in other areas. But is illegal for some sports.

Other pages









Got something to say? Make a comment.
Your name
Your email address
Message