cortisone

cortisone

[kawr-tuh-zohn, -sohn]
cortisone, 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). Cortisone is classed as a glucocorticoid with cortisol and corticosterone; its effects include increased glucose release from the liver, increased liver glycogen synthesis, and decreased utilization of glucose by the tissues. These actions tend to counter the effects of insulin and may aggravate or mimic diabetes in sufficiently high doses. Cortisone also exerts an effect on salt retention in the kidneys similar to that of aldosterone, although it is not as potent. The hormone causes increased breakdown of proteins and decreased protein synthesis, and large doses given over a long period of time may result in inhibited growth in children or weakening of bones and wasting of muscles in adults. The principal medical use of cortisone comes from its anti-inflammatory and antiallergic effects; it is extremely useful in the treatment of innumerable diseases including asthma and other allergic reactions, arthritis, and various skin diseases. Cortisone is necessary to maintain life and enable the organism to respond to stress; failure of the adrenal glands to synthesize cortisone (Addison's disease) or surgical removal of the adrenals is fatal unless cortisone is given as replacement therapy. Although less cortisone is manufactured in the body than either cortisol or corticosterone and although cortisone is less potent than cortisol, the term cortisone is often used collectively to include the other glucocorticoids, both the naturally occurring and the synthetic compounds such as prednisone. Small quantities of cortisone were first isolated from animal adrenals in 1935-36. A method of manufacture, involving laboratory synthesis from an acid of bile, was developed, and in 1949 cortisone was first offered commercially. The specific mechanisms by which cortisone and similar compounds act are still poorly understood.

Steroid hormone produced by the adrenal cortex (see adrenal gland). It participates in the regulation of the conversion of proteins to carbohydrates, and to some extent it regulates salt metabolism. Introduced medically in 1948 for its anti-inflammatory effect to treat arthritis, it has been largely replaced by related compounds that do not produce its undesired side effects, which include edema, increased stomach acidity, and imbalances in sodium, potassium, and nitrogen metabolism. Seealso Cushing syndrome.

Learn more about cortisone with a free trial on Britannica.com.

Cortisone (or /ˈkɔrtɨzoʊn/ (ˈkôrtəˌsōn or -zōn)) (17-hydroxy-11-dehydrocorticosterone) is a steroid hormone. Chemically, it is a corticosteroid closely related to corticosterone.

History

Cortisone was first discovered by the American chemist Edward Calvin Kendall while a researcher at the Mayo Clinic. He was awarded the 1950 Nobel Prize for Physiology or Medicine along with Philip S. Hench and Tadeus Reichstein for the discovery of adrenal cortex hormones, their structures, and functions. Cortisone was first produced commercially by Merck & Co..

Production

Cortisone is one of several end products of a process called steroidogenesis. This process starts with the synthesis of cholesterol which then proceeds through a series of modifications in the adrenal gland (suprarenal) to become any one of many steroid hormones. One end product of this pathway is cortisol. For cortisol to be released from the adrenal gland a cascade of signaling occurs. Corticotropin releasing hormone released from the hypothalamus stimulates corticotrophs in the anterior pituitary to release ACTH which relays the signal to the adrenal cortex. Here, the zona fasiculata and zona reticularis in response to ACTH secrete glucocorticoids, in particular cortisol. In the peripheral tissues cortisol is converted to cortisone by an enzyme called 11-beta-steroid dehydrogenase. Cortisol has much greater glucocorticoid activity than cortisone and thus cortisone can be considered an inactive metabolite of cortisol. However 11-beta-steroid dehydrogenase can catalyze the reverse reaction as well and thus cortisone is also the inactive precursor molecule of the active hormone cortisol. Cortisone is activated through hydrogenation of the 11-keto-group and is thus sometimes referred to as hydrocortisone.

Effects and uses

Cortisol, a glucocorticoid, and adrenaline are the main hormones released by the body as a reaction to stress. They elevate blood pressure and prepare the body for a fight or flight response.

Cortisone is sometimes used as a drug to treat a variety of ailments. It can be administered intravenously or cutaneously.

One of cortisone's effects on the body, and a potentially harmful side effect when administered clinically, is the suppression of the immune system. This could be the explanation for the apparent correlation between high stress and sickness. The suppression of the immune system may be important in the treatment of inflammatory conditions such as severe IgE-mediated allergies.

Cortisone is less powerful than a similar steroid cortisol. Cortisol is responsible for 95% of the effects of the glucocorticosteroids while cortisone is about 4 or 5%. Corticosterone is even less important. Cortisol decreases the uptake of glucose by cells and increases glucose release by the liver. This may cause hyperglycemia in a well-fed state but can maintain blood glucose levels in (stressful) fasting states.

References

  • Merck Index, 11th Edition, 2533
  • Woodward R. B., Sondheimer F., Taub D. (1951). "The Total Synthesis of Cortisone". Journal of the American Chemical Society 73 4057–4057.
  • Ingle D. J. (1950). "The biologic properties of cortisone: a review". Journal of Clinical Endocrinology 10 1312–1354.

See also

External links

Search another word or see cortisoneon Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature
FAVORITES
RECENT

;