| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 3,900,251,642 visitors served. |
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
glucocorticoid |
Also found in: Dictionary/thesaurus, Encyclopedia, Wikipedia | 0.01 sec. |
|
|
glucocorticoid /glu·co·cor·ti·coid/ (-kor´tĭ-koid)
1. any of the group of corticosteroids predominantly involved in carbohydrate metabolism, and also in fat and protein metabolism and many other activities (e.g., alteration of connective tissue response to injury and inhibition of inflammatory and allergic reactions); some also exhibit varying degrees of mineralocorticoid activity. In humans, the most important glucocorticoids are cortisol (hydrocortisone) and cortisone. 2. of, pertaining to, or resembling a glucocorticoid.
Glucocorticoid Any of a group of corticosteroids (as hydrocortisone or dexamethasone) that are anti-inflammatory and immunosuppressive, and that are used widely in medicine (as in the alleviation of the symptoms of rheumatoid arthritis).
glucocorticoid [glo̅o̅′kōkôr′təkoid] Etymology: Gk, glykys + L, cortex, bark; Gk, eidos, form an adrenocortical steroid hormone that increases gluconeogenesis, exerts an antiinflammatory effect, and influences many body functions. The most important of the three glucocorticoids is cortisol (hydrocortisone). Corticosterone is less active, and cortisone is inactive until converted to cortisol. Glucocorticoids promote the release of amino acids from muscle, mobilize fatty acids from fat stores, and increase the ability of skeletal muscles to maintain contractions and avoid fatigue. These hormones are known to stabilize mitochondrial and lysosomal membranes, increase the production of adenosine triphosphate, promote the formation of certain liver enzymes, and decrease antibody production and the number of circulating eosinophils. A deficiency of glucocorticoids is characterized by hyperpigmentation (bronzing) of the skin, fasting hypoglycemia, weight loss, and apathy. An excess is associated with elevated serum glucose levels, thinning of the skin, ecchymosis, osteoporosis, poor wound healing, increased susceptibility to infection, and obesity. Glucocorticoid secretion is stimulated by the adrenocorticotropic hormone of the anterior pituitary, which in turn is regulated by the corticotropin-releasing hormone of the hypothalamus and circulating cortiosol levels (negative feedback). Synthetic or semisynthetic glucocorticoids, derived chiefly from cortisol, include prednisone, prednisolone, dexamethasone, methylprednisolone, triamcinolone, and betamethasone. Compare mineralocorticoid. glucocorticoid [gloo″ko-kor´tĭ-koid] any corticoid substance that increases gluconeogenesis, raising the concentration of liver glycogen and blood glucose; the group includes cortisol, cortisone, and corticosterone. The release of glucocorticoids from the adrenal cortex is initially triggered by corticotropin-releasing hormone (CRH) elaborated by the hypothalamus. The target organ for this factor is the anterior lobe of the pituitary gland, which reacts to the presence of CRH by releasing corticotropin (ACTH). ACTH, in turn, stimulates the release of the glucocorticoids from the adrenal cortex. (See also adrenal gland.)
The principal glucocorticoid hormone is cortisol, which regulates the metabolism of proteins, carbohydrates, and lipids. Specifically, it increases the catabolism or breakdown of protein in bone, skin, muscle, and connective tissue. Cortisol also diminishes cellular utilization of glucose and increases the output of glucose from the liver. Because of their effects on glucose levels and fat metabolism, all the glucocorticoids are referred to as anti-insulin diabetogenic hormones. They increase the blood sugar level, raise the concentration of plasma lipids, and, when insulin secretion is insufficient, promote formation of ketone bodies, thus contributing to ketoacidosis. Other physiologic processes within the body can occur only in the presence of or with the “permission of€” the glucocorticoids. For example, the secretion of digestive enzymes by gastric cells and the normal excitability of myocardial and central nervous system neurons require a certain level of glucocorticoids. Glucocorticoids also promote transport of amino acids into the extracellular compartment, making them more readily available for the production of energy. In times of stress the glucocorticoids influence the effectiveness of the catecholaminesdopamine, epinephrine, and norepinephrine. For example, the presence of cortisol is essential to norepinephrine-induced vasoconstriction and other physiologic phenomena necessary for survival under stress. This particular property of cortisol demonstrates the one identifiable relationship between hormones from the adrenal cortex and those from the adrenal medulla. One of the medullary hormones is norepinephrine, which is secreted in large quantities when the gland is stimulated by the sympathetic nervous system in response to stress. Another effect of cortisol is that of dampening the body's inflammatory response to invasion by foreign agents. When present in large amounts, cortisol inhibits the release of histamine and counteracts potentially destructive reactions, such as increased capillary permeability and the migration of leukocytes. Since the immune response can damage body cells as well as those of foreign agents, the antiinflammatory protective mechanisms of cortisol help preserve the integrity of body cells at the site of the inflammatory response. glucocorticoid any corticoid substance that increases gluconeogenesis, raising the concentration of liver glycogen and blood sugar, i.e. cortisol (hydrocortisone), cortisone and corticosterone. These substances are widely used as anti-inflammatory agents; they are effective at terminating pregnancy if it is in the late stages and they are used as a management tool in cattle for that purpose.
dexamethasone sodium phosphate Pharmacologic class: Glucocorticoid Therapeutic class: Anti-inflammatory Pregnancy risk category C ActionUnclear. Reduces inflammation by suppressing polymorphonuclear leukocyte migration, reversing increased capillary permeability, and stabilizing leukocyte lysosomal membranes. Also suppresses immune response (by reducing lymphatic activity), stimulates bone marrow, and promotes protein, fat, and carbohydrate metabolism. AvailabilityElixir: 0.5 mg/5 ml Oral solution: 0.5 mg/5 ml, 1 mg/ml Solution for injection (sodium phosphate): 4 mg/ml, 10 mg/ml, 20 mg/ml, 24 mg/ml Tablets: 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 1.5 mg, 2 mg, 4 mg, 6 mg ⊘Indications and dosages ➣ Allergic and inflammatory conditions Adults: 0.75 to 9 mg/day (dexamethasone) P.O. as a single dose or in divided doses; in severe cases, much higher dosages may be needed. Dosage requirements vary and must be individualized based on disease and patient response. ➣ Cerebral edema Adults: Initially, 10 mg (sodium phosphate) I.V., followed by 4 mg I.M. q 6 hours. Then reduce dosage gradually over 5 to 7 days. ➣ Suppression test for Cushing's syndrome Adults: 1 mg P.O. at 11 P.M. or 0.5 mg P.O. q 6 hours for 48 hours (with urine collection testing, as ordered) Off-label uses• Acute altitude sickness Contraindications• Hypersensitivity to drug, benzyl alcohol, bisulfites, EDTA, creatinine, polysorbate 80, or methylparaben PrecautionsUse cautiously in: Administration• Give P.O. dose with food or milk.
Adverse reactionsCNS: headache, malaise, vertigo, psychiatric disturbances, increased intracranial pressure, seizures CV: hypotension, thrombophlebitis, myocardial rupture after recent myocardial infarction, thromboembolism EENT: cataracts GI: nausea, vomiting, abdominal distention, dry mouth, anorexia, peptic ulcer, bowel perforation, pancreatitis, ulcerative esophagitis Metabolic: decreased carbohydrate tolerance, hyperglycemia, cushingoid appearance (moon face, buffalo hump), decreased growth (in children), latent diabetes mellitus, sodium and fluid retention, negative nitrogen balance, adrenal suppression, hypokalemic alkalosis Musculoskeletal: muscle wasting, muscle pain, osteoporosis, aseptic joint necrosis, tendon rupture, long bone fractures Skin: diaphoresis, angioedema, erythema, rash, pruritus, urticaria, contact dermatitis, acne, decreased wound healing, bruising, skin fragility, petechiae Other: facial edema, weight gain or loss, increased susceptibility to infection, hypersensitivity reactions InteractionsDrug-drug. Barbiturates, phenytoin, rifampin: decreased dexamethasone effects Digoxin: increased risk of digoxin toxicity Ephedrine: increased dexamethasone clearance Estrogen, hormonal contraceptives: blocking of dexamethasone metabolism Fluoroquinolones: increased risk of tendon rupture Itraconazole, ketoconazole: increased dexamethasone blood level and effects Live-virus vaccines: decreased antibody response to vaccine, increased risk of adverse reactions Loop and thiazide diuretics: additive hypokalemia Nonsteroidal anti-inflammatory drugs: increased risk of GI adverse effects Somatrem, somatropin: decreased response to these drugs Drug-diagnostic tests. Calcium, potassium: decreased levels Cholesterol, glucose: increased levels Nitroblue tetrazolium test: false-negative result Drug-herbs. Echinacea: increased immune-stimulating effect Ginseng: potentiation of immune-modulating response Drug-behaviors. Alcohol use: increased risk of gastric irritation and GI ulcers Patient monitoring• Monitor blood glucose level closely in diabetic patients receiving drug orally. Patient teaching☞ Instruct patient to immediately report sudden weight gain, swelling of face or limbs, excessive nervousness or sleep disturbances, excessive body hair growth, vision changes, difficulty breathing, muscle weakness, persistent abdominal pain, or change in stool color. glucocorticoid Metabolism A steroid hormone that primarily affects carbohydrate metabolism and, to a lesser extent, fats and proteins Examples Cortisol–hydrocortisone, the major human glucocorticoid, cortisone; glucocorticoids are
produced naturally in the adrenal cortex, less in the gonads, can be synthesized; they have anti-inflammatory and immunosuppressive effects Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
|
| Medical Dictionary |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup |
|---|