1. The genomic action of aldosterone at the mineralocorticoid receptor (MR) in the distal nephron increases sodium reabsorption. Which transcriptional effect most directly mediates this?
A) Increased transcription of aquaporin-2 water channels
B) Increased transcription of epithelial sodium channel (ENaC) subunits and the Na/K-ATPase (sodium-potassium adenosine triphosphatase)
C) Increased transcription of the sodium-chloride cotransporter exclusively in the proximal tubule
D) Decreased transcription of ENaC subunits with compensatory channel insertion
E) Increased transcription of carbonic anhydrase in the collecting duct
ANSWER: B
Rationale:
Option B is correct. The aldosterone-MR complex binds mineralocorticoid response elements and increases transcription of the three epithelial sodium channel (ENaC) subunits and the basolateral Na/K-ATPase (sodium-potassium adenosine triphosphatase). The resulting apical sodium entry and basolateral extrusion drive sodium reabsorption, with potassium secreted as the counterion.
Option A: Option A is incorrect because aquaporin-2 transcription is principally a vasopressin-mediated effect on water permeability, not the mechanism of aldosterone-driven sodium reabsorption.
Option C: Option C is incorrect because the aldosterone-sensitive segment is the distal nephron and collecting duct acting through ENaC, not the proximal tubule sodium-chloride cotransporter.
Option D: Option D is incorrect because MR activation increases, not decreases, ENaC subunit transcription.
Option E: Option E is incorrect because carbonic anhydrase induction is not the mediator of aldosterone's sodium-retaining transcriptional program.
2. Which enzyme confers aldosterone selectivity at renal mineralocorticoid receptors (MR) by inactivating cortisol locally?
A) 5-alpha-reductase
B) Aldosterone synthase (CYP11B2)
C) Aromatase (CYP19A1)
D) 11beta-HSD2 (11-beta-hydroxysteroid dehydrogenase type 2), which converts cortisol to inactive cortisone
E) 21-hydroxylase (CYP21A2)
ANSWER: D
Rationale:
Option D is correct. 11beta-HSD2 (11-beta-hydroxysteroid dehydrogenase type 2) is co-expressed with MR in aldosterone-sensitive distal nephron cells and oxidizes cortisol to cortisone, which has negligible MR affinity. Because aldosterone is not a substrate, it selectively activates MR despite far higher circulating cortisol concentrations.
Option A: Option A is incorrect because 5-alpha-reductase converts testosterone to dihydrotestosterone and has no role in protecting renal MR.
Option B: Option B is incorrect because aldosterone synthase (CYP11B2) produces aldosterone in the zona glomerulosa; it does not inactivate cortisol at the receptor.
Option C: Option C is incorrect because aromatase converts androgens to estrogens and is unrelated to MR selectivity.
Option E: Option E is incorrect because 21-hydroxylase (CYP21A2) is a steroidogenic enzyme in cortisol and aldosterone synthesis, not the enzyme that guards renal MR from cortisol.
3. Which property best characterizes fludrocortisone among corticosteroids?
A) Markedly high mineralocorticoid potency relative to its glucocorticoid potency, making it the standard oral mineralocorticoid replacement agent
B) Pure glucocorticoid activity with no mineralocorticoid effect
C) Selective mineralocorticoid-receptor antagonism
D) Equivalent glucocorticoid and mineralocorticoid potency to hydrocortisone
E) Activity confined to the central nervous system with no renal effect
ANSWER: A
Rationale:
Option A is correct. Fludrocortisone is a synthetic fluorinated steroid with roughly 125-fold greater mineralocorticoid potency than hydrocortisone; although it also has glucocorticoid activity, it is dosed where that effect is negligible. It is the only oral mineralocorticoid replacement agent in routine use and is given at 50 to 200 micrograms per day in primary adrenal insufficiency.
Option B: Option B is incorrect because fludrocortisone's defining feature is potent mineralocorticoid activity, not pure glucocorticoid action.
Option C: Option C is incorrect because fludrocortisone is an MR agonist, not an antagonist (antagonists are spironolactone, eplerenone, finerenone).
Option D: Option D is incorrect because fludrocortisone is vastly more mineralocorticoid-potent than hydrocortisone, not equivalent.
Option E: Option E is incorrect because its principal action is renal sodium retention through MR, not a central nervous system effect.
4. Which pharmacological feature distinguishes spironolactone from eplerenone?
A) Spironolactone is non-steroidal whereas eplerenone is steroidal
B) Spironolactone is a mineralocorticoid-receptor agonist whereas eplerenone is an antagonist
C) Spironolactone antagonizes the androgen receptor (causing gynecomastia and sexual side effects) whereas eplerenone is selective for the mineralocorticoid receptor
D) Eplerenone is more potent at the mineralocorticoid receptor than spironolactone
E) Eplerenone uniquely carries an active metabolite (canrenone) absent from spironolactone
ANSWER: C
Rationale:
Option C is correct. Both are steroidal MR antagonists, but spironolactone also antagonizes the androgen receptor and has weak progestogenic activity, producing gynecomastia, decreased libido, and menstrual irregularities. Eplerenone was engineered for MR selectivity, with negligible androgen, progesterone, and glucocorticoid receptor affinity, so it avoids these endocrine effects.
Option A: Option A is incorrect because both spironolactone and eplerenone are steroidal; the non-steroidal MR antagonist is finerenone.
Option B: Option B is incorrect because both drugs are MR antagonists; neither is an agonist.
Option D: Option D is incorrect because eplerenone is roughly 60-fold less potent than spironolactone at MR, not more potent.
Option E: Option E is incorrect because canrenone is the active metabolite of spironolactone, not eplerenone.
5. Which set of properties correctly characterizes finerenone?
A) Steroidal MR antagonist with prominent androgen-receptor antagonism
B) MR agonist used for mineralocorticoid replacement
C) Steroidal MR antagonist with preferential renal tissue distribution and a long half-life
D) Selective glucocorticoid-receptor antagonist
E) Non-steroidal MR antagonist with high receptor selectivity, balanced heart and kidney tissue distribution, and a relatively short half-life
ANSWER: E
Rationale:
Option E is correct. Finerenone is a non-steroidal MR antagonist whose distinct binding mode yields high selectivity (no androgen, progesterone, or glucocorticoid receptor cross-reactivity), balanced distribution between heart and kidney, and a relatively short half-life of about 2 to 3 hours.
Option A: Option A is incorrect because finerenone is non-steroidal and lacks the androgen-receptor antagonism responsible for spironolactone's endocrine effects.
Option B: Option B is incorrect because finerenone blocks MR; it does not provide mineralocorticoid replacement.
Option C: Option C is incorrect because finerenone is non-steroidal with balanced cardiorenal distribution and a short half-life, unlike the steroidal, kidney-weighted, longer-acting agents.
Option D: Option D is incorrect because finerenone acts at MR, not the glucocorticoid receptor.
6. Which combination of findings is characteristic of primary adrenal insufficiency (AI) but not secondary AI?
A) Low plasma ACTH with hypernatremia and hypokalemia
B) Elevated plasma ACTH (adrenocorticotropic hormone) with hyperkalemia, hyponatremia, and postural hypotension
C) Elevated plasma ACTH with suppressed renin and hypokalemia
D) Low plasma ACTH with normal electrolytes and hyperpigmentation
E) Normal plasma ACTH with isolated hyperglycemia
ANSWER: B
Rationale:
Option B is correct. In primary AI the adrenal cortex is destroyed: loss of cortisol feedback raises ACTH (adrenocorticotropic hormone), and concurrent aldosterone deficiency produces hyperkalemia, hyponatremia, and postural hypotension. These mineralocorticoid-deficiency features are absent in secondary AI, where the zona glomerulosa is preserved.
Option A: Option A is incorrect because primary AI raises ACTH and causes hyperkalemia and hyponatremia, not low ACTH with hypernatremia and hypokalemia.
Option C: Option C is incorrect because aldosterone deficiency in primary AI raises renin (it is not suppressed) and causes hyperkalemia rather than hypokalemia.
Option D: Option D is incorrect because hyperpigmentation accompanies high ACTH; pairing it with low ACTH is internally inconsistent and describes neither form correctly.
Option E: Option E is incorrect because isolated hyperglycemia with normal ACTH is not a feature of primary AI, which typically causes hypoglycemia from glucocorticoid deficiency.
7. Why is hydrocortisone preferred over dexamethasone for routine glucocorticoid replacement in adrenal insufficiency?
A) Dexamethasone has greater mineralocorticoid activity, causing dangerous sodium loss
B) Hydrocortisone is more potent per milligram, allowing smaller tablets
C) Dexamethasone is not absorbed orally and must be injected
D) Hydrocortisone is identical to endogenous cortisol with a short half-life, allowing divided dosing that mimics the physiological diurnal rhythm and avoids prolonged axis suppression
E) Hydrocortisone has no glucocorticoid-receptor activity, reducing side effects
ANSWER: D
Rationale:
Option D is correct. Hydrocortisone is chemically identical to endogenous cortisol and has a short half-life (about 1.5 hours), so divided daily dosing can approximate the natural diurnal cortisol curve and avoids the prolonged hypothalamic-pituitary-adrenal axis suppression seen with long-acting agents such as dexamethasone.
Option A: Option A is incorrect because dexamethasone has essentially no mineralocorticoid activity; the contrast is its long duration, not sodium loss.
Option B: Option B is incorrect because hydrocortisone is less potent than dexamethasone per milligram; potency is not the reason for preference.
Option C: Option C is incorrect because dexamethasone is well absorbed orally.
Option E: Option E is incorrect because hydrocortisone is a full glucocorticoid-receptor agonist, which is exactly what provides effective replacement.
8. In which form of adrenal insufficiency (AI) is mineralocorticoid replacement with fludrocortisone required?
A) Primary AI, because destruction of the zona glomerulosa abolishes aldosterone production
B) Secondary AI, because pituitary failure abolishes aldosterone production
C) Tertiary AI, because hypothalamic failure abolishes aldosterone production
D) All forms of AI equally
E) No form of AI, because glucocorticoid alone always suffices
ANSWER: A
Rationale:
Option A is correct. Only primary AI destroys the zona glomerulosa and therefore abolishes aldosterone production, requiring fludrocortisone. In secondary and tertiary AI the zona glomerulosa remains responsive to the renin-angiotensin-aldosterone system, so mineralocorticoid replacement is unnecessary.
Option B: Option B is incorrect because secondary AI is pituitary in origin and leaves aldosterone production intact.
Option C: Option C is incorrect because tertiary AI is hypothalamic and likewise preserves renin-driven aldosterone secretion.
Option D: Option D is incorrect because mineralocorticoid replacement is needed only in primary AI, not in all forms.
Option E: Option E is incorrect because primary AI specifically does require mineralocorticoid replacement in addition to glucocorticoid.
9. Metyrapone lowers cortisol rapidly in severe hypercortisolism. Which biochemical change confirms its mechanism of action?
A) Accumulation of cholesterol due to side-chain cleavage blockade
B) Fall in 11-deoxycortisol as cortisol synthesis is restored
C) Accumulation of 11-deoxycortisol, the immediate precursor proximal to the CYP11B1 (11-beta-hydroxylase) step it inhibits
D) Rise in serum cortisol with suppressed ACTH
E) Accumulation of dihydrotestosterone from 5-alpha-reductase activation
ANSWER: C
Rationale:
Option C is correct. Metyrapone inhibits CYP11B1 (11-beta-hydroxylase), the final step converting 11-deoxycortisol to cortisol. The substrate proximal to the block, 11-deoxycortisol, accumulates, providing a biochemical marker that confirms enzyme inhibition while cortisol falls.
Option A: Option A is incorrect because cholesterol accumulation reflects side-chain cleavage (CYP11A1) blockade, not metyrapone's terminal-step inhibition.
Option B: Option B is incorrect because 11-deoxycortisol rises rather than falls, since the enzyme converting it to cortisol is blocked.
Option D: Option D is incorrect because cortisol falls (not rises) with metyrapone, and the drop in cortisol feedback tends to raise, not suppress, ACTH.
Option E: Option E is incorrect because dihydrotestosterone formation via 5-alpha-reductase is unrelated to metyrapone's action.
10. Osilodrostat was approved for Cushing disease in patients who are not surgical candidates or in whom surgery was not curative. Which description matches its pharmacology?
A) A glucocorticoid-receptor antagonist that blocks cortisol action peripherally
B) An adrenocorticolytic agent that destroys adrenocortical cells
C) A somatostatin analog acting on pituitary corticotrophs
D) A mineralocorticoid-receptor antagonist
E) An orally administered, potent and selective CYP11B1 (11-beta-hydroxylase) inhibitor that lowers cortisol synthesis
ANSWER: E
Rationale:
Option E is correct. Osilodrostat is an oral, potent, and selective inhibitor of CYP11B1 (11-beta-hydroxylase) with modest activity against aldosterone synthase at higher doses. It reduces cortisol synthesis and is given twice daily for Cushing disease in non-surgical or post-surgical-failure settings.
Option A: Option A is incorrect because glucocorticoid-receptor antagonism describes mifepristone, not osilodrostat.
Option B: Option B is incorrect because adrenocorticolytic destruction is the mechanism of mitotane.
Option C: Option C is incorrect because a somatostatin analog acting on corticotrophs describes pasireotide.
Option D: Option D is incorrect because osilodrostat is a steroidogenesis inhibitor, not an MR antagonist.
11. Which adverse effect and drug-interaction profile is characteristic of ketoconazole when used to lower cortisol?
A) Negligible hepatic risk with no clinically important drug interactions
B) Significant hepatotoxicity requiring liver-function monitoring, plus potent inhibition of CYP3A4 (cytochrome P450 3A4) causing many drug interactions
C) Hyperkalemia as the dose-limiting effect, as with mineralocorticoid-receptor antagonists
D) Hyperglycemia in most patients from islet somatostatin-receptor activation
E) Cerebellar ataxia at therapeutic concentrations
ANSWER: B
Rationale:
Option B is correct. Ketoconazole inhibits multiple steroidogenic enzymes and carries a significant hepatotoxicity risk, including rare acute liver failure, mandating baseline and periodic liver-function testing. It is also a potent inhibitor of CYP3A4 (cytochrome P450 3A4), raising concentrations of many co-administered drugs.
Option A: Option A is incorrect because hepatotoxicity and CYP3A4-mediated interactions are precisely the concerns that limit ketoconazole use.
Option C: Option C is incorrect because hyperkalemia is the signature of mineralocorticoid-receptor antagonists, not ketoconazole.
Option D: Option D is incorrect because hyperglycemia from islet somatostatin-receptor activation describes pasireotide.
Option E: Option E is incorrect because cerebellar ataxia at high concentrations is characteristic of mitotane toxicity, not ketoconazole.
12. Mifepristone differs mechanistically from steroidogenesis inhibitors used in Cushing syndrome. Which statement correctly describes its action and a consequence for monitoring?
A) It inhibits CYP11B1, so cortisol falls and urinary free cortisol (UFC) tracks response
B) It destroys adrenocortical tissue, so cortisol becomes undetectable
C) It activates the glucocorticoid receptor, intensifying cortisol effects
D) It antagonizes the glucocorticoid receptor (GR), so plasma cortisol and ACTH rise and cortisol-based measures such as UFC (urinary free cortisol) become unreliable for monitoring
E) It blocks the mineralocorticoid receptor, so potassium rises but cortisol is unchanged
ANSWER: D
Rationale:
Option D is correct. Mifepristone is a competitive glucocorticoid-receptor (GR) antagonist; it blocks cortisol action rather than reducing synthesis. Because GR also mediates negative feedback, blocking it raises plasma cortisol and ACTH (adrenocorticotropic hormone), so UFC (urinary free cortisol) and late-night salivary cortisol cannot track efficacy. Clinical and glycemic endpoints are used instead.
Option A: Option A is incorrect because mifepristone is not a steroidogenesis inhibitor; cortisol rises rather than falls, and UFC is unreliable.
Option B: Option B is incorrect because mifepristone does not destroy adrenocortical tissue; that describes mitotane.
Option C: Option C is incorrect because mifepristone antagonizes, rather than activates, the glucocorticoid receptor.
Option E: Option E is incorrect because mifepristone's relevant target here is the glucocorticoid receptor; while it can unmask mineralocorticoid effects, it is not primarily an MR blocker and cortisol is not unchanged.
13. Which adverse effect is most characteristic of pasireotide, and why?
A) Hyperglycemia, because somatostatin-receptor activation in pancreatic islets suppresses insulin and incretin secretion
B) Hyperkalemia, because of mineralocorticoid-receptor blockade
C) Hepatotoxicity, because of broad steroidogenic enzyme inhibition
D) Gynecomastia, because of androgen-receptor antagonism
E) Cerebellar ataxia, because of accumulation in adipose tissue
ANSWER: A
Rationale:
Option A is correct. Pasireotide is a somatostatin analog that activates somatostatin receptor subtype 5 on corticotroph adenoma cells to reduce ACTH (adrenocorticotropic hormone). Its hallmark adverse effect is hyperglycemia, occurring in roughly 70% of patients, because somatostatin-receptor activation in pancreatic islets suppresses insulin and incretin secretion.
Option B: Option B is incorrect because hyperkalemia is the dose-limiting effect of mineralocorticoid-receptor antagonists, not pasireotide.
Option C: Option C is incorrect because hepatotoxicity from broad enzyme inhibition characterizes ketoconazole.
Option D: Option D is incorrect because gynecomastia from androgen-receptor antagonism is a spironolactone effect.
Option E: Option E is incorrect because cerebellar ataxia from adipose accumulation reflects mitotane toxicity.
14. Which statement best describes mitotane?
A) A selective CYP11B1 inhibitor used as first-line oral therapy for Cushing disease
B) A glucocorticoid-receptor antagonist used for hyperglycemia in Cushing syndrome
C) An adrenocorticolytic agent used primarily for adrenocortical carcinoma that requires supraphysiological glucocorticoid replacement because it raises corticosteroid-binding globulin and induces glucocorticoid metabolism
D) A mineralocorticoid-receptor antagonist used in heart failure
E) A somatostatin analog that suppresses ACTH from corticotroph adenomas
ANSWER: C
Rationale:
Option C is correct. Mitotane produces selective cytotoxic destruction of adrenocortical cells (adrenocorticolytic effect) and is used primarily for adrenocortical carcinoma. Because it raises corticosteroid-binding globulin (lowering free cortisol) and induces CYP3A4 (accelerating glucocorticoid metabolism), patients require glucocorticoid replacement at two to three times the usual dose.
Option A: Option A is incorrect because the selective CYP11B1 inhibitor for Cushing disease is osilodrostat, not mitotane.
Option B: Option B is incorrect because glucocorticoid-receptor antagonism for hyperglycemia describes mifepristone.
Option D: Option D is incorrect because mitotane is not an MR antagonist.
Option E: Option E is incorrect because a somatostatin analog suppressing corticotroph ACTH describes pasireotide.
15. What is the therapeutic goal of glucocorticoid dosing in congenital adrenal hyperplasia (CAH)?
A) To completely normalize serum 17-hydroxyprogesterone, even if higher doses are required
B) To maximize linear growth by using the highest tolerated glucocorticoid dose
C) To replace mineralocorticoid activity without affecting ACTH
D) To stimulate adrenal androgen production for normal pubertal development
E) To use the smallest glucocorticoid dose that adequately suppresses ACTH (adrenocorticotropic hormone) and androgen precursors while preserving normal growth
ANSWER: E
Rationale:
Option E is correct. In CAH the aim is to give just enough glucocorticoid to suppress ACTH (adrenocorticotropic hormone)-driven overproduction of androgen precursors while avoiding the growth impairment and Cushingoid effects of excess dosing. Mild elevation of precursors is accepted rather than full normalization.
Option A: Option A is incorrect because normalizing 17-hydroxyprogesterone usually requires glucocorticoid excess; guidelines accept mild elevation to protect growth.
Option B: Option B is incorrect because high doses impair, rather than maximize, linear growth.
Option C: Option C is incorrect because the glucocorticoid component specifically acts by suppressing ACTH; it is not a mineralocorticoid-sparing strategy.
Option D: Option D is incorrect because therapy aims to reduce excess adrenal androgens, not stimulate them.
16. Which laboratory abnormality is the principal dose-limiting adverse effect shared by spironolactone, eplerenone, and finerenone?
A) Hypocalcemia
B) Hyperkalemia
C) Hyponatremia from excessive potassium loss
D) Hyperglycemia
E) Elevated transaminases from direct hepatotoxicity
ANSWER: B
Rationale:
Option B is correct. All mineralocorticoid-receptor antagonists reduce renal potassium secretion, so hyperkalemia is the principal dose-limiting adverse effect, requiring potassium monitoring, especially with reduced renal function or concurrent renin-angiotensin-aldosterone system blockade.
Option A: Option A is incorrect because these agents do not characteristically cause hypocalcemia.
Option C: Option C is incorrect because, although MR antagonism promotes natriuresis, the dose-limiting concern of the class is hyperkalemia, not hyponatremia from potassium loss; these drugs retain potassium.
Option D: Option D is incorrect because hyperglycemia is the signature of pasireotide, not of MR antagonists.
Option E: Option E is incorrect because direct hepatotoxicity with transaminase elevation characterizes ketoconazole, not the MR antagonist class.
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