Steroid

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, animals, and fungi. Their most important role in most living systems is as hormones.

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

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.

Cholesterol is an important steroid alcohol, 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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