AskDefine | Define steroids

User Contributed Dictionary

English

Noun

steroids
  1. Plural of steroid

Derived terms

Extensive Definition

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 the sterol cycloartenol (plants). Both sterols are derived from the cyclization of the triterpene squalene.

Origin

Steroids include estrogen (US spelling) or oestrogen (UK/AUS spelling), 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.

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:

External links

steroids in Arabic: ستيرويد
steroids in Bulgarian: Стероид
steroids in Catalan: Esteroide
steroids in Czech: Steroidy
steroids in German: Steroide
steroids in Spanish: Esteroide
steroids in Esperanto: Steroido
steroids in French: Stéroïde
steroids in Korean: 스테로이드
steroids in Croatian: Steroidi
steroids in Italian: Steroide
steroids in Hebrew: סטרואיד
steroids in Malay (macrolanguage): Steroid
steroids in Dutch: Steroïde
steroids in Japanese: ステロイド
steroids in Norwegian: Steroid
steroids in Occitan (post 1500): Esteroïd
steroids in Polish: Steroidy
steroids in Portuguese: Esteróide
steroids in Romanian: Steroid
steroids in Russian: Стероиды
steroids in Simple English: Steroid
steroids in Slovak: Steroid
steroids in Serbian: Стероиди
steroids in Serbo-Croatian: Steroidi
steroids in Finnish: Steroidi
steroids in Swedish: Steroid
steroids in Thai: สเตอรอยด์
steroids in Turkish: Steroid
steroids in Chinese: 類固醇
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