Steroid part 1 Flashcards
What are the three zones of the adrenal cortex, and what hormones do they secrete?
- Zona Glomerulosa: Secretes mineralocorticoids (Aldosterone) under control of the Renin-angiotensin system.
- Zona Fasciculata: Secretes glucocorticoids (cortisol) under control of ACTH.
- Zona Reticularis: Secretes androgens (sex hormones).
What is the role of the hypothalamic-pituitary-adrenal (HPA) axis in cortisol regulation?
The hypothalamus releases CRH (Corticotropin Releasing Hormone), which stimulates the anterior pituitary to release ACTH (Adrenocorticotropic Hormone). ACTH then stimulates the adrenal cortex to produce cortisol (CORT). Cortisol provides negative feedback to the hypothalamus and pituitary to regulate its own production.
What is the primary use of Fludrocortisone, and how does it differ from other steroids?
Fludrocortisone has powerful sodium and water-retaining activity and is used to replace aldosterone in Addison’s disease.
What are the metabolic effects of glucocorticoids (GC) on carbohydrate metabolism?
Glucocorticoids increase gluconeogenesis, decrease peripheral utilization of glucose, and cause hyperglycemia, thereby antagonizing the action of insulin.
How do glucocorticoids affect protein metabolism?
Glucocorticoids increase protein breakdown (proteolysis), decrease the conversion of amino acids to proteins, and cause a negative nitrogen balance, leading to muscle wasting, growth retardation in children, and delayed wound healing.
What are the immunological effects of glucocorticoids?
Glucocorticoids inhibit B cell function, leading to decreased antigen-antibody reactions, and inhibit T cell function, leading to decreased inflammatory mediators and cytokines (e.g., interleukins, TNF, TGFB, PDGF). They also inhibit macrophage activity, stabilize lysosome membranes, inhibit mast cells, and decrease histamine release and capillary permeability.
What are the cardiovascular effects of glucocorticoids?
Glucocorticoids cause hypertension due to sodium and water retention and increased sensitivity of blood vessels to circulating catecholamines. They also have anti-shock effects due to their hypertensive and cardiovascular system effects and anti-inflammatory actions.
What are the hematological effects of glucocorticoids?
Glucocorticoids increase RBC and neutrophil counts, decrease lymphocyte and eosinophil counts, increase coagulation factors, and increase plasma lipids, cholesterol, and triglycerides.
What is the mechanism of action of glucocorticoids through gene regulation?
Glucocorticoids bind to a receptor in the cytosol, and the steroid-receptor complex translocates into the nucleus to bind to target genes, resulting in gene expression (upregulation). This leads to the formation of proteins and enzymes with wide-ranging metabolic effects, such as enhancing the formation of lipocortin, which inhibits phospholipase A2, thereby inhibiting the release of arachidonic acid and subsequent inflammatory pathways.
What are the side effects of inhaled corticosteroids like Beclomethasone and Budesonide?
The main side effects of inhaled corticosteroids like Beclomethasone and Budesonide are hoarseness of voice and oropharyngeal candidiasis.
What is the effect of glucocorticoids on bone metabolism?
Glucocorticoids increase calcium excretion and decrease bone matrix (collagen), leading to bone loss.
What is the effect of glucocorticoids on growth in children?
Glucocorticoids cause growth retardation and decrease growth hormone secretion.
What are the therapeutic uses of corticosteroids in autoimmune diseases?
Corticosteroids are used in autoimmune diseases such as vasculitis, ulcerative colitis, rheumatoid arthritis, and systemic lupus erythematosus (SLE).
Why are corticosteroids used in organ transplantation?
Corticosteroids are used in organ transplantation to prevent rejection.
What corticosteroid is used to stimulate lung maturation in the fetus, and why is it preferred?
Betamethasone is used to stimulate lung maturation in the fetus. It is preferred because it has less maternal protein binding, allowing increased transfer across the placenta to the fetus.
What are the side effects of chronic corticosteroid use on the eye?
Chronic use of corticosteroids on the eye may cause cataracts and raised intraocular pressure (glaucoma).
What is the risk of sudden cessation after prolonged corticosteroid administration?
Sudden cessation after prolonged administration can cause acute adrenal insufficiency.
What are the contraindications for corticosteroid use?
Contraindications include the presence of infections (viral infections and TB), diabetes mellitus (relative), hypertension and heart failure (relative), peptic ulcer (relative), and early pregnancy (may cause cleft palate).
What drug is used to inhibit the synthesis of adrenal steroid hormones in cases of adrenal tumors?
Metyrapone is used to inhibit the synthesis of adrenal steroid hormones, particularly in cases of adrenal tumors.
What corticosteroid is used to reduce cerebral edema after brain surgery or cerebrovascular accident (CVA)?
Dexamethasone is used to reduce cerebral edema after brain surgery or cerebrovascular accident (CVA).
What are the side effects of corticosteroids on the musculoskeletal system?
Side effects include muscle weakness (myopathy), hypokalemia, osteoporosis, increased incidence of vertebral fractures, and avascular necrosis (especially of the femoral head).
What is the risk of chronic corticosteroid use on the skin?
Chronic corticosteroid use can cause skin atrophy, increased capillary fragility, bruising, and striae.
What is the role of aminoglutethimide in corticosteroid synthesis?
Aminoglutethimide blocks the conversion of cholesterol to pregnenolone, causing a reduction in the synthesis of all hormonally active steroids. It is used in the treatment of breast cancer and Cushing’s syndrome due to adrenocortical cancer.
What are the potential side effects of corticosteroids on the cardiovascular system?
Side effects include hypertension, edema due to sodium and water retention, hyperlipidemia, and a hypercoagulable state due to increased platelet count.
What is the mechanism of action of ketoconazole in Cushing’s syndrome?
Ketoconazole is a potent non-selective inhibitor of adrenal and gonadal steroid synthesis, making it useful in the treatment of Cushing’s syndrome.
What is the effect of corticosteroids on the immune system?
Corticosteroids increase the incidence of infections and can reactivate dormant tuberculosis (TB) due to immunosuppression.
What is the role of trilostane in corticosteroid synthesis?
Trilostane is a 3β-17 hydroxysteroid dehydrogenase inhibitor that interferes with the synthesis of adrenal and gonadal hormones.
What is the role of metyrapone in testing adrenal function?
Metyrapone is used in tests of adrenal function by inhibiting 11-beta-hydroxylase, which is important in the synthesis of hydrocortisone.
