steroids are not illegal....they r also used in medical
treatments
In chemistry and biology, steroids are a type of lipid,
characterized by a carbon skeleton with four fused rings. Hundreds
of distinct steroids have been identified in plants and animals.
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 conversation, 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.
Different steroids vary in the functional groups attached to these
rings. 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, including atherosclerosis.
Most other steroids are synthesized from cholesterol. Also, various
hormones, including vertebrate sex hormones, are steroids created
from cholesterol.
There are also various specific categories of steroids,
including:
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, manufactured
by bodybuilding supplement companies
Steroid hormones have 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.
