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63 Cards in this Set

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IS cortisol required for the synthesis of epinephrine?
yes
what is the role of 11B-HSD?
a set of isoenzymes that is involved in regulating cortisol activity in different tissues.

In the kidney, colon, and salivary gland: it works to INACTIVATE cortisol (to cortisone)

IN the liver, adipose tissue, bone and eye, 11B-HSD favours the conversion of cortisone into the active form (cortisol)
what is cortisol's effect on gonadal function?
it inhibits response of pituitary to GnRH (thus decreased gonadotropins and gonadal steroids)
what is cortisol's effect on teh CNS? initially? Later?
initially: euphoria
later: irritability, memory loss, etc.
cortisol's effect on the thyroid?
inhibits TSH secretion
where in the kidney does aldosterone act?
distal tubules
aldosterone is a (strong/weak) glucocorticoid?
weak
of DHEAS, DHEA and androstenedione, which has the longest t1/2?
DHEAS
Explain how ADRENAL ANDROGEN production varies throughout life? What changes does cortisol production undergo throughout life?
Adrenarche - age 6-10
peaks - age 30
adrenopause - production decreases as we age (corresponds to atrophy of ZR)

Cortisol production does not change with age
when we say adrenal steroids, what are we talking about?
all the hormones made by the ZG, ZF, ZR
all adrenal steroids synthesis begins with...
cholesterol
what is the rate limiting step in the synthesis of adrenal androgens? What stimulates this reactino in teh ZG? What stimulates this reaction in teh ZF and ZR?
cholesterol --> pregnenolone
ZG: AII
ZF and ZR: ACTH
What is the role of P450 enzymes in the synthesis of adrenal steroids?
they hydroxylate the steroid molecules
what drug will interfere with the synthesis of adrenal androgens through its actuion of inhibiting p450 enzymes?
ketoconazole
why will does hi ACTH often correspond with increased pigmentation?
ACTH is a spliced product of the POMC gene protein. Another product is MSH. Thus a high ACTH means that MSH is also being produced.
what is the immediate precursor to cortisol? Why do I care about the precursor?
11-deoxycortisol
IT will accumulate in 11-B-hydroxylate deficiency (testing for increased levels of this is the DIAGNOSTIC TEST for 11-hydroxylate deficiency)
after cholesterol is made into pregnenolone, what is the next step?
pregnenolone --> progesterone
what percentage of cortisol is bound to CBG (cortisol binding globulin)
90% (only 10% is free in teh circulation)
what are the two SCREENING tests for cushings?
Urine free cortisol
Low-dose dexamethasone
what is the main blood carrier for adrenal androgens? Testosterone?
adrenal androgens= albumin. Testosterone = SHBG (sex hormone binding globulin)
what are the 2 fates of cortisol in teh circulation?
1. either metabolised in the liver to glucuronide OR
2. passed into the urine
what are 2 things that can override the negative feedback of cortisol on the hypothal & pituitary? (i.e. what will determine cortisol levels more that cortisol itself?) What is the MOA?
1. stress
-physical (trauma)
-emotional (e.g. depression)
-hypoglycemia
-severe illness (via cytokines: IL-1, TNF-alpha, IL-6)
2. circadian rhythm (diurnal)

Both of these act via stimulating CRH secretion
what are estrogen's (via BCPs, pregnancy.) effects on cortisol concentration in the blood?
estrogen will increase CBG (made by liver), and therefore cortisol in the blood. However, the amount of free cortisol will stay the same.
Illness or malnutrition will (increase/decrease) CBG in the blood?
decrease
3 main factors that control aldosterone release from the ZG:
1. REnin - RAS
2. K+
3.ACTH (minor short-term effects)
what does renin do?
catalyses conversino of angiotensinogen to angiotensin I
what changes angiotensin I to angiotensin II?
ACE
how will postural change affect renin secretion?
renin will increase in an upright position
ANP,BNP,and CNP are relased by the atria, ventricles and vascular endothelium in response to (hi/low) filling pressure and volume. They (stimulate/suppress) the RAS system
hi
Suppress (causing natriuresis)
with illness, adrenal androgens (increase/decrease) while cortisol (increase/decreases)
androgens - decrease (think, less sex drive when sick)
cortisol - increases (ahhh! body is stressed!)
has DHEA been shown to have anti-aging effects?
no!
can DHEA supplementation be important for women with adrenal insufficiency?
YES!
what are the 4 primary causes of adrenal insufficiency?
1. Autoimmune adrenalitis (m/c cause of Addison's disease)
2. Granulomatous disease (e.g. TB)
3. Congenital adrenal hyperplasia (21 or 11 hydroxylase deficiency)
4.Adrenoleukodystrophy (accumulation of VLCFAs)
what is the m/c secondary cause of hypocortisolism?
iatrogen (i.e. long term glucocorticoid Tx)
what will you see in Primary hypocortisolism in terms of
a. ACTH levels
b. Cortisol levels
c. aldosterone levels?
In primary hypocortisolism
a. ACTH levels will be up
b. cortisol levels will be down
c. aldosterone levels will be down
what is Type II Autoimmune Polyglandular Syndrome (APS-11)= Schmidt's Syndrome?
It's when Addisons' disease is part of a syndrome (i.e the autoimmune aspect of it affects other glands suchas :
-thyroid
-pancreatic B cells --> insulin dependent DM
-ovaries
-melanocytes
-parathyroid

recall Mrs. Addison picture
what 2 symptoms of addisons disease are important features that can lead to an addisonian crisis?
hyperkalemia
low blood pressure leading to cirdculatory collapse
what enzyme is deficient in adrenoleukodystrophy?
a peroxisomal enzyme that catabolizes VLCFAs
what is the presentation of adrenoleukodystrophy?
neurological +/- adrenal symptoms
Adrenoleukodystrophy shoudl be considered a cause of Addison's disease in (males/females_
males (it is x-linked)
the rapid ACTH stimulation test is used for?
to test for adrenal insufficiency (primary or secondary)
If the result of a rapid ACTH stimulation test are as follows, what is the diagnosis?
-normal baseline ACTH
-increase in cortisol after injection
Not Addison's disease
if the result of the rapid ACTH stimulation test is as follows, what is your diagnosis:
-low baseline ACTH
-blunted cortisol response after injection
secondary cause or atrophy due to chronic glucocorticoid Tx
if the result of the rapid ACTH stimulation test is as follows, what is your diagnosis:
-hi baseline ACTH
-blunted cortisol response after injection
primary cause of adrenal insufficiency (e.g. Addison's disease)
If you determine the cause of adrenal insufficiency to be due to a secondary cause in the rapid ACTH stimulation test, what should you do next?
Confirm that it really is a secondary cause by testing the whole axis via an insulin-induced hypoglycemia test. If the patient cannot recover, then this confirms that their problem is due to the pituitary or hypothalamus
Treatment for primary adrenal insufficiency?
glucocorticoid AND mineralocorticoid

+ DHEA in females
Treatment for a secondary adrenal insufficiency?
glucocorticoid only (AII will take care of the aldosterone)

+ DHEA in females
what is the main cause of Conn's syndrome?
an aldosterone secreting adenoma (70%)...the other 30% are idiopathic
what will you see in Conn's syndrome in terms of:
a. aldosterone level?
b. renin level?
c. blood pressure?
d. potassium status?
1. increased aldo
2. low renin
3. hi BP
4. hypokalemia
what are teh 4 symptoms of HYPOkalemia
1. muscle weakness
2. abnormal glucose tolerance
3. polyuria (due to nephrogenic DI)
4. ECG changes
is hypokalemia a/w acidosis or alkalosis?
alkalosis. Low serum K will result in cells pumping K out from their insides. This is a K/H pump that is going this. So H+ ions are going to move INTO cells, causing alkalosis
Secondary hyperaldosteronism is due to things that cause increased renin. What are 3 examples of things that will cause an increase in renin?
1. renal artery stenosis
2. renin secreting tumor
3. coarctation of the aorta
How do you diagnose hyperaldosteronism?
RENIN:ALDOSTERONE ratio.
Summary:
1. Diagnosis of adrenal insuffiency?
2. Diagnosis of hyperaldosteronism
3. SCREENING of Cushing's
1. rapid ACTH stimulation test
2. renin:aldosterone ratio
3. urine free cortisol, low-dose dexamethasone supression test
when would you run a bilateral adrenal venous sampling of aldosterone?
when you suspect a primary cause of hyperaldosteronism (Conn's syndrome).
what is the Tx for primary hyperaldosteronism?
surgical resection
What 2 diseases do Congenital Adrenal Hyperplasia refer to?
Diseases that will increase ACTH secretion, therefore accounting for the adrenal hyperplasia: Namely:
1. 21 hydroxylase deficiency
2. 11 hydroxylase deficiency
What is the definitive dx test for 21 hydroxylase deficiency? What is the definitive dx test for 11 hydroxylase deficiency?
17-hydroxyprogesterone

11-deoxycortisol
what is the Tx for 21-hydroxylase deficiency?

what is the tx for 11-hydroxylase deficiency?
21: glucocorticoid and mineralocorticoid

11: glucocorticoid only.
Drugs and hormones that act via nuclear receptors can be remembered by "GREAT Football Game". What do the letters stand for?
Glucocorticoids
Retinoids (acne)
Estrogen(HRT)
Androgens (HRT)
Thyroid hormone
Fibrates
Glitazones
The nuclear receptors that glucocorticoids bind to form (hetero/homo) dimers

the nuclear receptors that Thyroid hormone binds to form (hetero/homo) dimers
glucocorticoids: homo

TH: hetero
the anti-inflammatory effect of glucocorticoids is primarily due to the (shutting off/switching on) of genes
shutting off (3 mechs)
what are the 3 mechs by which glucocorticoids work to shut off genes?
1. stimulates production of IkB, which binds to NFkB interfering with the production of cytokines
2. interferes with AP-1 (normally involved in regulating expression of collagenase)
3. interferes with CBP/P300 - needed for transcription of many genes