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27 Cards in this Set
- Front
- Back
What type of tissue does the adrenal cortex develop from?
what does the 2 month gestational inner adrenal cortex first produce? what does the outter gestational portion produce? |
- mesoderm
- DHEA-S - nothing |
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What are the branch points for each of these?
glucocorticoid mineralcorticoid (aldosterone) testosterone estrogen |
glucocorticoid: C=O @ 3,20
mineralcorticoid (aldosterone):CH=O @ 18 testosterone: C-19=O @ 3, OH at 17 estrogen: C-18, aromatic ring |
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What enzyme is necessary to convert Cholesterol to Pregnenolone? Where does this take place?
what converts pregnenolone to cortisol? where? What rxn occurs BACK in the mitochondrion??? what drug inhibits this rxn? |
17-alpha-hydroxylase! in the mitochondrion
11-deoxycortisol to cortisol, by 11-hydroxylase. in the endoplasmic reticulum 11-hydroxylase, which converts to cortisol. metyrapone. |
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What does ACTH do?
What is Cholesterol Desomolase? What drugs inhibits it and blocks cortisol formation? |
Increases Cholesterol Uptake – For use by Adrenal Cortex
Desmolase is activated by ACTH, increasing conversion of cholesterol to pregnenolone to create cortisol. Aminoglutetheamide |
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What enzyme produces aldosterone (mineralcorticoid) in the zona glomerulosa?
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18-hydroxylase in the mitochondrion (21-beta-hydroxylase also)
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What binds cortisol, what increases/decreases levels?
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Cortisol Binding Globulin (CBG), albumin and some free.
CBG levels are increased by estrogen, decreased by liver or kidney failure. liver normally metabolizes cortisol within an hour of release. |
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What binds aldosterone? What happens to it if it isn't used?
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weakly (50%) binds albumin, mostly free. It is eaten up by the liver within 20 mins of release, excreted by the kidneys.
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What is the androgen A ring reduced to, and where do they come from?
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Reduced to 17-ketosteroids
2/3 urinary ketosteroids from adrenal 1/3 are from gonads |
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What is stress' effect on ACTH?
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ACTH will increase, via cAMP will stimulate desmolase and 11-hydroxylase to cleave more cortisol and release it.
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What is ACTH controlled by?
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stress
cortisol diurnal variation |
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What is the glucocorticoid effect on energy stores?
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- increase appetite
- increase protein catabolism - amplify effects of epinephrine and GLUCAGON (starvation chemical) - increase gluconeogenesis in the liver - increase hepatic glucogenesis and ketogenesis - decrease peripheral glucose use, shifts it to the brain and heart. - inhibits insulin action to increase FFA and glycerol in the blood. - permissive to epinephrine and GH to mobilize fat from BRS: - immunosuppressive - maintenance of vascular responsiveness to catecholamines/epinephrine/norepi - increase GFR - CNS: loss of concentration, increase sense of smell and taste - inhibits bone formation - decrease Ca absorption in GI tract - increase calcium excretion by kidney - inhibits TSH GH release in high dose |
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How are adrenal androgens important in women?
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- pubic, axillary hair development
- libido - excess amounts causes virilization |
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Is aldosterone essential? What does it act on and where is it stored?
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Yes. In order to live, you must use aldosterone's effects to reabsorb sodium at the kidneys.
It acts on the renin-angiotensin system. Renin is stored in the JG cells, in close contact with macula densa sensory cells in the distal tubule. |
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How does renin work?
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Cleaves angiotensinogen to angiotensin I in the liver.
angiotensin I is cleaved in the lung by ACE (with chloride) to become angiotensin II. adrenal cortex can make angiotensin III if it needs to. |
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What triggers renin release?
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- low sodium
- low JG stretch - beta adrenergic stimulation |
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angiotensin II effects
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- increase aldosterone
- increase in vasoconstriction - increase in ADH (vasopressin) - increase in thirst |
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How important is ACTH stimulation of aldosterone?
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maintains basal stimulation of aldosterone, but has no effect on daily, minute to minute regulation of aldosterone.
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What are renin inhibitors?
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Captopril: ACE inhibitor
Saralsin: AT-II antagonist Atrial Natriuretic Peptide: inhibits renin secretion |
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What is the difference between aldosterone and ADH?
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ADH only increases permeability to water at the collecting duct.
aldosterone increases sodium for potassium exchange at the distal tubule, acting passively. |
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What is spironolactone?
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An aldosterone antagonist.
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What is Addison's Disease?
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- adrenal insufficiency (can be caused by destruction of the adrenal cortex)
- ACTH deficiency results in decreased cortisol, aldosterone, androgens. - negative feedback from low cortisol secretion can give increased ACTH release. - HYPOGLYCEMIA - weight loss, weakness, nausea, vomiting - hyperpigmentation - ECF volume contraction - hyperkalemia, hypotension, metabolic acidosis - no cortisol = no stress tolerance, decrease GFR, increase BUN lack of androgens: - reduction in body hair - anemia Tx: glucocorticoid replacement, salt, glucose, and a mineralcorticoid |
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What is Cushing's syndrome?
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pituitary tumor. can be caused by overuse of glucocorticoids.
- facial, truncal obesity - osteoperosis - muscle atrophy - decreased wound healing - diabetes - decreased immunity - headaches, insomnia - ACTH oversecretion will lead to virilization, menstrual disorders. |
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How do you diagnose cushings?
How do you test with dexamethosone? |
High cortisol levels
High ACTH levels Inject dexa, and if it can't suppress the ACTH levels, then you know there is an ACTH tumor present. If you have high cortisol but low ACTH, then you know the tumor is in the adrenal and not a result of over-release of ACTH from the pituitary. |
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What is Conn's Syndrome? How can you treat it?
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Hyperaldosteronism. It's like excess renin production.
Excess sodium/water retention. Potassium wasting, hypokalemic. You get HTN and polyuria. You can treat it with SPIRONOLACTONE, aldosterone antagonist. |
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What two enzyme deficiencies lead to androgenital syndrome?
What happens with high DHEA? |
21-beta-hydroxylase (most)
11-beta-hydroxylase without 21-beta, ACTH increases and piles up steroids and they get shunted into producing ANDROGENS. These DHEA androgens make body hair appear to early, and you get salt wasting. You can treat with cortisol. |
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What specifically happens in 11-beta deficiency?
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overproduction of 11-deoxycortisol, which also gives you strong androgen production. Symptoms include virilization and hypertension.
You treat both 11 and 21 symptoms with cortisol. |
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What happens win deficiencies with:
1) 3-beta-hydroxylase 2) desmolase 3) 17-alpha-hydroxylase |
1) 3-beta-hydroxylase: can only make sex hormones
2) desmolase: fatal, no steroids at all 3) 17-alpha-hydroxylase: no sex hormones, cortisol build up gives HTN |