steroidu

Steroids are a broad class of organic compounds based on the steroid nucleus, a fused arrangement of four carbon rings. They include natural substances such as cholesterol and a range of hormone molecules, as well as numerous synthetic derivatives. The term steroidi or steroid is used in various languages to refer to these compounds.

Natural steroids are produced in the body and can be grouped into several families. Corticosteroids, produced in the adrenal cortex, include glucocorticoids (involved in metabolism and immune response) and mineralocorticoids (role in electrolyte balance). Sex steroids—androgens, estrogens, and progestogens—are mainly produced in the gonads and contribute to sexual development and reproduction. Neurosteroids are steroids formed in the brain and nervous system with functional roles in neural signaling. Cholesterol serves as a central precursor for many other steroids.

Pharmacologically important steroids are used widely in medicine. Glucocorticoids such as prednisone and dexamethasone have anti-inflammatory and immunosuppressive effects. Mineralocorticoids help regulate salt and water balance. Hormone therapies modulate or replace natural sex steroids in various conditions. Synthetic anabolic steroids have been used to promote muscle growth and, controversially, to enhance athletic performance; their nonmedical use is associated with health risks and is subject to regulation and doping controls.

Mechanisms of action typically involve binding to intracellular receptors that act as transcription factors, leading to changes in gene expression and protein synthesis. Side effects depend on the steroid class and dose and can include metabolic changes, bone loss, hypertension, liver injury, mood alterations, and suppression of the hypothalamic–pituitary–adrenal axis with withdrawal symptoms after long-term use.

Manufacture and regulation of steroids vary globally. They can be produced industrially for pharmaceuticals or occur naturally in the body, and their use is governed by medical, legal, and sporting authorities to prevent misuse.