Hormones are glandular chemical secretions generally formed by an organ or part of the body and carried in the bloodstream to another organ or part of the body to stimulate or retard a specific physiological activity or process. Steroidal hormones are a distinctive type of hormone which encompasses a large group of chemical compounds that are widely distributed throughout the body and involved in many important structural and functional physiological roles. Steroids are a class of lipid-soluble molecules, including cholesterol, bile acids, vitamin D, and hormones, that share a common four-ring structure based on cyclopentanoperhydrophenanthrene and that carry out a wide variety of functions.
Steroid hormones are widely used for fertility control and in anti-inflammatory treatments for physical injuries and diseases such as arthritis, asthma, and auto-immune disorders. Progesterone, a naturally occurring progestin, is primarily used to treat amenorrhea, abnormal uterine bleeding, or as a contraceptive. Steroids such as cortisone and dexamethasone are potent immune suppressants and are used to treat conditions such as autoimmune diseases, organ transplant rejection, arthritis, skin, mucosal membrane and ophthalmic inflammation, as well as neoplastic conditions such as lymphoma. Steroid hormones are highly lipophilic and act through nuclear receptors rather than through receptors on the plasma membrane. Steroid hormone receptors have been shown to support the development of cancer in the breast, prostate, uterus, cervix, and ovaries. Steroids are classified into about five classes according to their physiological activities, as follows: sex hormones of androgen (androsterone, testosterone, etc.) and estrogen (estradiol, etc.) playing a critical role in the development of secondary sex characteristics in men and women, respectively, gestogen (progesterone, etc.) stimulating and maintaining pregnancy, glucocorticoid (cortisone, hydrocortisone, etc.) stimulating gluconeogenesis and increasing liver glycogen levels by catabolism of proteins, and mineralcorticoid (deoxycorticosterone, aldosterone, etc.) playing a important role in maintaining the balance of electrolytes and water in a body.
The use of steroidal hormones is well known in modern clinical therapy. Examples of such hormones are corticoids, anabolic agents and various progesterones. Therapeutic uses of steroidal hormone replacement therapy have been developed and are being used clinically as means for increasing or supplementing the hormone balance of biological organisms, as well as for treating a wide variety of other clinical conditions. Anabolic steroids, such as testosterone and natural and synthetic derivatives and substitutes, affect many metabolic activities such as muscular development and fat distribution. Administration of anabolic steroids tend to take users past their natural or genetic limits to create body size and muscle mass beyond that which is optimal to the genetic makeup of the individual and past that which can be effectively supported by the various organs of the body. Testosterone is the principal male hormone and is required for the development and maintenance of secondary sexual characteristics, libido and spermatogenesis. Testosterone also has anabolic properties, in promoting in muscle growth and maintenance. Lower than normal testosterone levels in men have been associated with low energy, frailty, depression, decreased libido, weakness, lethargy, loss of lean body and bone mass and impotence. Nandrolone is known as substances with anabolic activity. One of the best known nandrolone esters is nandrolone decanoate, which finds use in medicine as an injection preparation with a pronounced and protracted protein-sparing effect. There are a variety of deleterious side effects associated with prolonged or high doses of steroids, such as fatigue, muscle wasting, bone loss resulting in pathologic fractures, salt and fluid retention, hypertension and heart disease, immunosuppression and infection, and avascular necrosis of the weight bearing articular surfaces of bones, such as the hips. Excess anabolic steroids tend to suppress or dam up other natural, yet essential, hormones in the body such as the andrenocorticosteroids. The glucocorticoids, and cortisol (hydrocortisone) in particular, are necessary in the metabolism of carbohydrates and fats.
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