adrenal steroids Flashcards
where is aldosterone produced
in the glomerulosa
where is cortisol produced?
in the fasciculata
where are androgens produced?
in the reticularis
what are the two precursors to all pathways in the adrenal
cholesterol and pregnenolone
what is the aldosterone pathway?
21-beta hydroxylase, 11-beta hydroxylase and aldosterone synthase.
what is the cortisol pathway?
requires the precursor made by 17 alpha hydroxylase (17-hydroxpregnenolone). then it is 21 hyrox, 11 hydrox, to cortisol
what is the androgen pathway?
requires precursors made by 17 alpha, DHEA androstenedione, testosterone, estradiol (androgen).
what is the role of glucocorticoids?
cortisol allows the body to handle stress. theres re receptors everywhere through out the body. the best known functions are immune function and carbohydrate metabolism
what are the metabolic effects of glucocorticoids.
increase gluconeogenesis in the liver, release amino acids through muscle breakdown, inhibits peripheral glucose uptake. stimulates lipolysis.
what is the goal of glucocorticoid metabolic modulation?
producing food for the brain! it is a counter regulatory hormone.
what does cortisol do tot he immune system
it has potent antiinflammatory effects. it up regulates anti-inflammatory proteins, down regulates proinflam proteins, and causes decreased leukocyte presence at the sites of inflammation.
what other roles does cortisol have>
fetal lung development. cognitive functions throughout the nervous system., also has weak mineralocorticoid function
what is the mechanism of action of mineralocorticoid>
binds the Aldosterone receptor in cytoplasm. active in the principle cells of the collecting tubules in the kidney. increases na/kATPase expression and the epithelial sodium channel expression.
what is the job of aldosterone?
to maintain the vascular volume. there is increased reabsorption of sodium and water, and increased renal excretion of potassium.
what is the significance of 11-beta-hydroxysteroid dehydrogenase?
it breaks down cortisol in cells that are responsive to aldosterone. because cortisol has weak mineralocorticoid stimulation this is required to stop cortisol from overwhelming the entire system,
what regulates aldosterone secretion?
concentration of potassium in the extracellular fluid. angiotensin II. ACTH and sodium deficiency have a small effect
symptoms of cushings
weight gain, menstrual irregularity, hirsutism, psychiatric dysfunction, backache, muscle weakness, fractures, loss of scalp hair.
what are sign of cushing’s
truncal obesity, plethora, moon face, HTN, bruising, thin skin, red-purple striae, proximal myopathy, ankle edema.
diagnosis of cushing’s
ACTH, 24hr urine free cortisol excretion, low dose dexamethisone suppression test. midnight salivary cortisol. diagnosis requires at least two of these to be positive.
what characterizes an ACTH dependent process
when there is high ACTH and high cortisol
what characterizes an ACTH independent process?
when there is low ACTH and high cortisol.
aminoglutethimide?
treats cushing’s by inhibiting the conversion of cholesterol to pregnenolone.
ketoconazole
treats cushing’s by inhibiting adrenal and gonadal synthesis. this is an anti fungal derivative. it is a nonselective inhibitor
mitotane
cushing’s treatment. related to DDT insecticide, nonselective cytotoxic action on the adrenal cortex. has a bad side effect panel.