Steroid

A steroid is a lipid characterized by a carbon skeleton with four fused rings. Different steroids vary in the functional groups attached to these rings. Hundreds of distinct steroids have been identified in plants and animals. Their most important role in most living systems is as hormones.

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In human physiology and medicine, the most important steroids are cholesterol, the steroid hormones, and their precursors and metabolites.

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In conversations, the term steroid is often used more restrictively in specific contexts. For instance, steroid in common medical usage by non-endocrinologists usually refers to corticosteroids, nearly always glucocorticoids. In an athletic or body-building context, steroid commonly refers to anabolic steroids.

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Cholesterol is an important steroid, being a common component of animal cell membranes. However, a high level of it can cause various conditions and diseases, such as atherosclerosis. Most other steroids are synthesized from cholesterol. Also, various hormones, including vertebrate sex hormones, are steroids created from cholesterol.

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There are also various specific categories of steroids, including:

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• Anabolic steroids - used by athletes to increase performance
• Corticosteroids - affects metabolism and electrolyte excretion
• Sex hormones - androgens, estrogens, and progestagens
• Prohormones - precursors to actual steroid hormones. They were manufactured by bodybuilding supplement companies until they were banned from the supplement market.

Steroid hormones produce their physiological effects by binding to steroid hormone receptor proteins. The binding of steroid hormones to their receptors causes changes in gene transcription and cell function.

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Steroid: Synthesis ►



 

Lipid: The term lipid comprises a diverse range of molecules and to some extent is a catchall for relatively water-insoluble or nonpolar compounds of biological origin, including waxes, fatty acids, fatty-acid derived phospholipids, sphingolipids, glycolipids and terpenoids, such as retinoids and steroids....

Carbon: :Alternative meaning: Carbon (API)...

Functional group: In ecology functional groups are collections of organisms based on morphological, physiological, behavioral, biochemical, or environmental responses or on trophic criteria....