Pharmacology Endocrine System Pharmacology 2 — Questions and Answers
Question 1: Clomiphene citrate stimulates ovulation primarily by:
- Directly stimulating the ovaries with FSH-like activity
- Providing exogenous LH to trigger ovulation
- Blocking hypothalamic estrogen receptors to increase GnRH release (Correct answer)
- Suppressing progesterone to allow follicle development
Correct answer: Blocking hypothalamic estrogen receptors to increase GnRH release
Clomiphene blocks estrogen receptors in the hypothalamus, preventing negative feedback and increasing GnRH pulsatility, which raises FSH and LH to stimulate ovulation.
Question 2: Ketoconazole can be used to treat Cushing's syndrome because it:
- Blocks ACTH receptors in the adrenal cortex
- Inhibits cortisol synthesis by blocking steroidogenic enzymes (Correct answer)
- Stimulates negative feedback on pituitary ACTH secretion
- Antagonizes glucocorticoid receptors in peripheral tissues
Correct answer: Inhibits cortisol synthesis by blocking steroidogenic enzymes
Ketoconazole inhibits CYP11A1 and CYP11B1, blocking key enzymatic steps in cortisol biosynthesis within the adrenal cortex.
Question 3: Desmopressin (DDAVP) is primarily indicated for treating:
- Syndrome of inappropriate ADH (SIADH)
- Adrenal insufficiency
- Central diabetes insipidus (Correct answer)
- Type 2 diabetes mellitus
Correct answer: Central diabetes insipidus
Desmopressin is a synthetic ADH (vasopressin) analog used to replace deficient ADH in central diabetes insipidus, reducing excessive water loss.
Question 4: Octreotide is used to manage acromegaly because it:
- Blocks IGF-1 receptors in peripheral tissues
- Is a somatostatin analog that suppresses GH secretion (Correct answer)
- Directly antagonizes growth hormone receptors
- Activates dopamine receptors to inhibit the pituitary
Correct answer: Is a somatostatin analog that suppresses GH secretion
Octreotide mimics somatostatin, binding somatostatin receptors on somatotrophs to inhibit GH secretion and consequently reduce IGF-1 levels.
Question 5: Bisphosphonates (e.g., alendronate) treat osteoporosis primarily by:
- Stimulating osteoblast differentiation and bone formation
- Providing supplemental calcium directly to bone matrix
- Inhibiting osteoclast-mediated bone resorption (Correct answer)
- Increasing intestinal calcium and phosphate absorption
Correct answer: Inhibiting osteoclast-mediated bone resorption
Bisphosphonates bind hydroxyapatite and are taken up by osteoclasts, impairing their function and inducing apoptosis to reduce bone resorption.
Question 6: Bromocriptine is used to treat hyperprolactinemia because it acts as a:
- Prolactin receptor antagonist
- Dopamine D2 receptor agonist at anterior pituitary lactotrophs (Correct answer)
- GnRH analog that suppresses pituitary hormones
- Serotonin antagonist that reduces prolactin release
Correct answer: Dopamine D2 receptor agonist at anterior pituitary lactotrophs
Bromocriptine activates D2 dopamine receptors on pituitary lactotrophs, mimicking dopamine's tonic inhibitory control over prolactin secretion.
Question 7: Fludrocortisone is primarily used for its:
- Potent anti-inflammatory glucocorticoid effects
- Immunosuppressive properties in autoimmune disease
- Mineralocorticoid effects to replace aldosterone (Correct answer)
- Anabolic effects on muscle and bone
Correct answer: Mineralocorticoid effects to replace aldosterone
Fludrocortisone is a potent synthetic mineralocorticoid used to replace aldosterone in primary adrenal insufficiency (Addison's disease), promoting sodium retention.
Pharmacology Endocrine System Pharmacology 2
Clomiphene citrate stimulates ovulation primarily by: