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steroids,class of lipidslipids,
a broad class of organic products found in living systems. Most are insoluble in water but soluble in nonpolar solvents. The definition excludes the mineral oils and other petroleum products obtained from fossil material.
..... Click the link for more information. having a particular molecular ring structure called the cyclopentanoperhydro-phenanthrene ring system. Steroids differ from one another in the structure of various side chains and additional rings. Steroids are common in both plants and animals. In humans, steroids are secreted by the ovaries and testes, the adrenal cortex (see adrenal glandadrenal gland
or suprarenal gland
, endocrine gland (see endocrine system) about 2 in. (5.1 cm) long situated atop each kidney. The outer yellowish layer (cortex) of the adrenal gland secretes about 30 steroid hormones, the most important of which are aldosterone and
..... Click the link for more information. ), and the placenta.
The range of steroids is diverse, including several forms of vitamin D, digitalis, sterols (e.g., cholesterolcholesterol
, fatty lipid found in the body tissues and blood plasma of vertebrates; it is only sparingly soluble in water, but much more soluble in some organic solvents. A steroid, cholesterol can be found in large concentrations in the brain, spinal cord, and liver.
..... Click the link for more information. ), and the bile acids. Many steroids are biologically active hormoneshormone,
secretory substance carried from one gland or organ of the body via the bloodstream to more or less specific tissues, where it exerts some influence upon the metabolism of the target tissue.
..... Click the link for more information. that control a number of the body's metabolic processes. This group includes the male sex hormone testosteronetestosterone
, principal androgen, or male sex hormone. One of the group of compounds known as anabolic steroids, testosterone is secreted by the testes (see testis) but is also synthesized in small quantities in the ovaries, cortices of the adrenal glands, and placenta, usually
..... Click the link for more information. and the female sex hormones estrogenestrogen
, any one of a group of hormones synthesized by the reproductive organs and adrenal glands in females and, in lesser quantities, in males. The estrogens cause the thickening of the lining of the uterus and vagina in the early phase of the ovulatory, or menstrual, cycle
..... Click the link for more information. and progesteroneprogesterone
, female sex hormone that induces secretory changes in the lining of the uterus essential for successful implantation of a fertilized egg. A steroid, progesterone is secreted chiefly by the corpus luteum, a group of cells formed in the ovary after the follicle
..... Click the link for more information. . The steroid hormones of the adrenal cortex include glucocorticoids such as cortisonecortisone
, steroid hormone whose main physiological effect is on carbohydrate metabolism. It is synthesized from cholesterol in the outer layer, or cortex, of the adrenal gland under the stimulation of adrenocorticotropic hormone (ACTH).
..... Click the link for more information. and cortisolcortisol
steroid hormone that in humans is the major circulating hormone of the cortex, or outer layer, of the adrenal gland. Like cortisone, cortisol is classed as a glucocorticoid; it stimulates liver glycogen formation while it decreases the rate
..... Click the link for more information. (see also corticosteroid drugcorticosteroid drug
, any one of several synthetic or naturally occurring substances with the general chemical structure of steroids. They are used therapeutically to mimic or augment the effects of the naturally occurring corticosteroids, which are produced in the cortex of the
..... Click the link for more information. ) and mineralocorticoids such as aldosteronealdosterone
, steroid secreted by the cortex of the adrenal gland. It is the most potent hormone regulating the body's electrolyte balance. Aldosterone acts directly on the kidney to decrease the rate of sodium-ion excretion (with accompanying retention of water), and to
..... Click the link for more information. .
Natural or synthetic steroids are used in oral contraceptives and in the treatment of arthritisarthritis,
painful inflammation of a joint or joints of the body, usually producing heat and redness. There are many kinds of arthritis. In its various forms, arthritis disables more people than any other chronic disorder.
..... Click the link for more information. , Addison's diseaseAddison's disease
[for Thomas Addison], progressive disease brought about by atrophy of the outer layer, or cortex, of the adrenal gland; it is also called chronic adrenocortical insufficiency.
..... Click the link for more information. , and certain skin ailments. Side effects, related to dosage and length of treatment, can be serious and include high blood pressure, edema, unwanted hair growth, and menstrual cycle disruption. Anabolic steroidsanabolic steroid
or androgenic steroid
, any of a group of synthetic derivatives of testosterone that promote muscle and bone growth. Used to treat uncontrolled weight loss in wasting diseases, anabolic steroids have also been taken by bodybuilders and athletes seeking
..... Click the link for more information. , male hormones given to build up strength in seriously ill patients, have been abused by bodybuilders and athletes in an attempt to increase muscle mass and strength.