Endocrine Pharmacology Practice Questions

Q: What is a known effect of steroids?

Prevent de-iodination. **Explanation:** **1. Why "Prevent de-iodination" is correct:** Glucocorticoids (steroids) inhibit the enzyme **5'-deiodinase**, which is responsible for the peripheral conversion of the pro-hormone **T4 (Thyroxine)** into its metabolically active form, **T3 (Triiodothyronine)**. By blocking this conversion, steroids effectively lower the circulating levels of active T3. This property is clinically exploited in the management of **Thyroid Storm**, where high doses of steroids (like Dexamethasone or Hydrocortisone) are used to rapidly reduce metabolic activity. **2. Why other options are incorrect:** * **A. Increase TSH:** Steroids actually **suppress** the secretion of Thyroid Stimulating Hormone (TSH) from the anterior pituitary. Chronic steroid use can lead to a state of secondary hypothyroidism or blunted TSH response. * **B. Increased FSH:** Steroids generally exert a negative feedback effect on the hypothalamic-pituitary-gonadal (HPG) axis. High levels of glucocorticoids inhibit the release of GnRH, which leads to a **decrease** in FSH and LH levels, often causing menstrual irregularities or decreased libido. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drugs inhibiting peripheral T4 to T3 conversion:** Remember the mnemonic **"PTU"** (Propylthiouracil, Propranolol, Steroids/Prednisolone, and Amiodarone). * **Steroids in Thyroid Storm:** They serve a dual purpose—inhibiting T4 to T3 conversion and treating potential relative adrenal insufficiency associated with severe thyrotoxicosis. * **Metabolic Effects:** Steroids cause hyperglycemia (gluconeogenesis), proteolysis (muscle wasting), and lipolysis (redistribution of fat).

Q: Exenatide is prescribed for which disease?

Diabetes. **Exenatide** is a synthetic analog of **Glucagon-Like Peptide-1 (GLP-1)**, which is an incretin hormone. It is primarily used in the management of **Type 2 Diabetes Mellitus**. ### Why Diabetes is Correct: Exenatide acts as a **GLP-1 Receptor Agonist**. It lowers blood glucose through several mechanisms: * **Glucose-dependent insulin secretion:** It stimulates the pancreas to release insulin only when blood sugar levels are high, reducing the risk of hypoglycemia. * **Glucagon suppression:** It inhibits post-prandial glucagon secretion. * **Gastric emptying:** It slows down the rate at which the stomach empties, leading to a slower absorption of glucose. * **Satiety:** It acts on the hypothalamus to increase satiety, often leading to significant **weight loss**. ### Why Other Options are Incorrect: * **A. Osteoporosis:** Treatment typically involves Bisphosphonates, Teriparatide (PTH analog), or Denosumab. Exenatide has no role in bone mineral density management. * **C. Hyperthyroidism:** Managed with antithyroid drugs like Carbimazole, Methimazole, or Propylthiouracil. Notably, GLP-1 agonists are contraindicated in patients with a history of Medullary Thyroid Carcinoma. * **D. Infertility:** Treated with ovulation inductors like Clomiphene citrate or Letrozole. While weight loss from Exenatide might indirectly help PCOS patients, it is not a primary treatment for infertility. ### High-Yield NEET-PG Pearls: * **Source:** Originally derived from the saliva of the **Gila monster** (*Heloderma suspectum*). * **Administration:** Given **subcutaneously**. Liraglutide is another common drug in this class; Semaglutide is available in both oral and injectable forms. * **Major Side Effect:** Gastrointestinal upset (nausea/vomiting) is most common. A rare but serious complication is **Acute Pancreatitis**. * **Benefit:** It is "cardioprotective" and preferred in diabetics with established atherosclerotic cardiovascular disease (ASCVD).

Q: An elderly male patient has benign prostatic hyperplasia. Which of the following medications can be used to suppress prostatic growth?

Finasteride. The correct answer is **Finasteride**. **1. Why Finasteride is correct:** Benign Prostatic Hyperplasia (BPH) is driven by **Dihydrotestosterone (DHT)**, a potent androgen synthesized from testosterone by the enzyme **5α-reductase** [1]. Finasteride is a competitive inhibitor of 5α-reductase (specifically Type II). By blocking the conversion of testosterone to DHT, it reduces the size of the prostate gland over time (usually 6–12 months), improves urinary flow, and reduces the need for surgery. **2. Why the other options are incorrect:** * **Spironolactone:** A potassium-sparing diuretic that also acts as an aldosterone and androgen receptor antagonist [1]. While it has anti-androgenic side effects (like gynecomastia), it is not a standard treatment for suppressing prostatic growth in BPH. * **Ketoconazole:** An antifungal that inhibits steroid synthesis (CYP450 enzymes) [1]. While it can lower testosterone levels, its high toxicity and side-effect profile make it unsuitable for BPH management. * **Flutamide:** A pure non-steroidal androgen receptor antagonist. It is primarily used in the treatment of **prostate cancer**, not BPH, as it does not effectively shrink the prostate in benign conditions and carries a risk of hepatotoxicity. **3. NEET-PG High-Yield Pearls:** * **Finasteride vs. Dutasteride:** Finasteride inhibits Type II 5α-reductase; Dutasteride inhibits both Type I and II. * **Clinical Use:** Finasteride is also used for **Male Pattern Baldness** (Androgenetic Alopecia). * **Side Effects:** Decreased libido and erectile dysfunction. * **PSA Levels:** 5α-reductase inhibitors can decrease PSA levels by approximately 50%; this must be accounted for when screening for prostate cancer. * **Immediate Relief:** For rapid symptomatic relief of BPH, **α1-blockers** (e.g., Tamsulosin) [2, 3] are preferred as they relax prostatic smooth muscle without affecting gland size.

Q: All of the following drugs cause hyperprolactinemia EXCEPT:

Bromocriptine. **Explanation:** The regulation of prolactin secretion is primarily under the inhibitory control of **Dopamine**, which acts on **D2 receptors** in the anterior pituitary (Tuberoinfundibular pathway). Any drug that increases dopaminergic activity will decrease prolactin, while any drug that blocks D2 receptors will cause **hyperprolactinemia**. **Why Bromocriptine is the Correct Answer:** Bromocriptine is a potent **D2 receptor agonist**. By stimulating the dopamine receptors in the pituitary, it mimics the natural inhibitory effect of dopamine, thereby **decreasing** prolactin levels. It is clinically used in the management of prolactinomas and galactorrhea. **Why the Other Options are Incorrect:** * **Haloperidol & Chlorpromazine:** These are typical antipsychotics that act by blocking D2 receptors in the brain. By blocking these receptors in the tuberoinfundibular pathway, they remove the "dopamine brake," leading to significantly elevated prolactin levels. * **Metoclopramide:** This is a prokinetic and antiemetic drug that also acts as a central D2 receptor antagonist. It is a well-known cause of drug-induced hyperprolactinemia and gynecomastia. **High-Yield NEET-PG Pearls:** 1. **Dopamine = Prolactin Inhibiting Hormone (PIH).** 2. **Tuberoinfundibular Pathway:** The specific dopaminergic pathway responsible for prolactin regulation. 3. **Other drugs causing hyperprolactinemia:** Reserpine (depletes dopamine), Methyldopa, Verapamil, and SSRIs. 4. **Clinical Presentation:** In females, hyperprolactinemia presents as galactorrhea, amenorrhea, and infertility; in males, it causes gynecomastia and erectile dysfunction.

Q: Which of the following is a GLP-1 analogue used in the management of diabetes mellitus?

Exenatide. **Explanation:** **Correct Option: A. Exenatide** Exenatide is a **GLP-1 (Glucagon-Like Peptide-1) receptor agonist**, also known as an **Incretin Mimetic**. GLP-1 is an incretin hormone secreted by the L-cells of the intestine in response to food. It lowers blood glucose by stimulating glucose-dependent insulin secretion, inhibiting glucagon release, and slowing gastric emptying. Exenatide is a synthetic version of exendin-4 (found in Gila monster saliva) and is resistant to degradation by the enzyme DPP-4. **Incorrect Options:** * **B. Pramlintide:** This is a synthetic **Amylin analogue**. It is used as an adjunct to insulin in both Type 1 and Type 2 DM to suppress glucagon and slow gastric emptying. * **C. Sitagliptin:** This is a **DPP-4 inhibitor** (Gliptin). It works by preventing the breakdown of endogenous GLP-1, thereby increasing its half-life. It is an oral drug, unlike GLP-1 analogues which are typically injectable. * **D. Canagliflozin:** This is an **SGLT-2 inhibitor** (Gliflozin). It acts on the proximal convoluted tubule of the kidney to inhibit glucose reabsorption, leading to glucosuria. **High-Yield Clinical Pearls for NEET-PG:** * **Weight Loss:** GLP-1 analogues (e.g., Liraglutide, Semaglutide) are highly effective for weight loss due to increased satiety. * **Cardiovascular Benefit:** Liraglutide and Semaglutide have proven benefits in reducing major adverse cardiovascular events (MACE). * **Side Effects:** The most common side effects are GI-related (nausea/vomiting). A rare but serious association is **Acute Pancreatitis**. * **Contraindication:** They are contraindicated in patients with a personal or family history of Medullary Thyroid Carcinoma (MTC) or MEN 2 syndrome.

Q: Which of the following is a long-acting insulin?

Detemir. ### Explanation **Correct Option: D (Detemir)** Insulin Detemir is a **long-acting (basal) insulin analog**. Its prolonged duration of action (up to 24 hours) is achieved through a unique chemical modification: the addition of a **myristic acid (C14 fatty acid chain)** to the lysine at position B29. This modification allows the insulin molecule to bind to **albumin** in both the subcutaneous tissue and the bloodstream. The slow dissociation from albumin results in a stable, peakless plasma concentration, making it ideal for providing basal insulin coverage. **Incorrect Options:** * **A, B, and C (Lispro, Aspart, Glulisine):** These are **ultra-short-acting (rapid-acting) insulin analogs**. They are designed to dissociate rapidly into monomers after subcutaneous injection, leading to a quick onset (5–15 minutes) and short duration (3–5 hours). They are used specifically for **prandial (mealtime)** glucose control. **High-Yield NEET-PG Pearls:** 1. **Long-acting Analogs:** Include **Glargine** (precipitates at physiological pH), **Detemir** (albumin binding), and **Degludec** (forms multi-hexamers; longest half-life >40 hours). 2. **Peakless Profile:** Unlike NPH (intermediate-acting), long-acting analogs are "peakless," which significantly reduces the risk of **nocturnal hypoglycemia**. 3. **Weight Neutrality:** Detemir is often associated with less weight gain compared to other insulin formulations. 4. **Afrezza:** A rapid-acting **inhaled** insulin; contraindicated in smokers and COPD/Asthma patients. 5. **IV Use:** Only **Regular (soluble) Insulin** is typically used intravenously for managing Diabetic Ketoacidosis (DKA).

Q: Mechanism of action of sildenafil is:

Phosphodiesterase-5 inhibitor. **Explanation:** **Mechanism of Action (Correct Answer: C):** Sildenafil is a potent and selective inhibitor of **Phosphodiesterase-5 (PDE-5)**. Under normal physiological conditions, sexual stimulation leads to the release of Nitric Oxide (NO) in the corpus cavernosum. NO activates the enzyme guanylyl cyclase, which increases levels of **cyclic Guanosine Monophosphate (cGMP)**. cGMP causes smooth muscle relaxation and increased blood flow, resulting in an erection. PDE-5 is the enzyme responsible for the degradation of cGMP. By inhibiting PDE-5, sildenafil prevents the breakdown of cGMP, thereby enhancing the vasodilatory effect of NO and maintaining penile erection. **Analysis of Incorrect Options:** * **A. 5-alpha reductase inhibitor:** These drugs (e.g., **Finasteride**, Dutasteride) block the conversion of Testosterone to Dihydrotestosterone (DHT). They are used in Benign Prostatic Hyperplasia (BPH) and male pattern baldness. * **B. Antiandrogen:** These agents (e.g., **Flutamide**, Spironolactone) block androgen receptors or inhibit androgen synthesis. They are used in conditions like prostate cancer or hirsutism. * **D. Androgenic:** These are drugs that mimic male sex hormones (e.g., Methyltestosterone) used for replacement therapy in hypogonadism. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindication:** Sildenafil must **never** be co-administered with **Nitrates** (e.g., Nitroglycerin) as it can cause life-threatening hypotension due to synergistic increases in cGMP. * **Other Uses:** Sildenafil is also FDA-approved for **Pulmonary Arterial Hypertension (PAH)**. * **Side Effects:** Common side effects include headache, flushing, and **blue-tinted vision (Cyanopsia)** due to weak inhibition of PDE-6 in the retina. * **Tadalafil vs. Sildenafil:** Tadalafil has a much longer half-life (~36 hours), often called the "weekend pill."

Q: Which of the following is used to treat Laron's dwarfism?

Mecasermin. Explanation Correct Answer: C. Mecasermin Mechanism and Rationale: Laron’s dwarfism (Growth Hormone Insensitivity Syndrome) is a rare genetic disorder caused by a mutation in the Growth Hormone (GH) receptor . In these patients, GH levels are normal or high, but the liver cannot produce Insulin-like Growth Factor-1 (IGF-1) in response to GH. Since the defect is at the receptor level, administering exogenous GH is ineffective. Mecasermin , a recombinant human IGF-1 (rhIGF-1), bypasses the defective GH receptor and directly stimulates systemic growth, making it the treatment of choice [1]. Analysis of Incorrect Options: A. Sermorelin: A synthetic GHRH analogue used to stimulate the pituitary to release GH. It is ineffective in Laron's dwarfism because the pathology lies downstream of the pituitary. B. Tesamorelin: A GHRH analogue specifically used to reduce excess abdominal fat in HIV-infected patients with lipodystrophy. C. Ganirelix: A GnRH antagonist used primarily in controlled ovarian hyperstimulation to prevent premature LH surges. It has no role in growth disorders. High-Yield Clinical Pearls for NEET-PG: Diagnosis of Laron's: Characterized by short stature, prominent forehead, depressed nasal bridge, high serum GH , and very low serum IGF-1 . Mecasermin Side Effect: The most common adverse effect is hypoglycemia (due to IGF-1's insulin-like effects). Patients are advised to consume a snack shortly before or after injection [1]. Somatropin vs. Mecasermin: Use Somatropin (rhGH) for GH deficiency; use Mecasermin for GH resistance (Laron's).

Q: Cinacalcet acts by which of the following mechanisms?

Decreasing parathyroid hormone secretion. **Mechanism of Action** Cinacalcet is a **calcimimetic** agent. It works by increasing the sensitivity of **calcium-sensing receptors (CaSR)** located on the chief cells of the parathyroid gland to extracellular calcium. By mimicking the action of calcium, it "tricks" the gland into sensing that calcium levels are high, thereby suppressing the synthesis and release of **Parathyroid Hormone (PTH)**. **Analysis of Options** * **Option A (Inhibiting RANK-ligand):** This is the mechanism of **Denosumab**, a monoclonal antibody used in osteoporosis to prevent osteoclast maturation. * **Option B (Activating osteoblasts):** Teriparatide (recombinant PTH 1-34) acts as an anabolic agent by stimulating osteoblasts when given in intermittent doses. * **Option D (Increasing Vitamin D levels):** Vitamin D analogs (like Calcitriol or Paricalcitol) are used to suppress PTH, but Cinacalcet does not increase Vitamin D; in fact, it is often used alongside Vitamin D sterols. **Clinical Pearls for NEET-PG** * **Indications:** Secondary hyperparathyroidism in Chronic Kidney Disease (CKD) on dialysis and Parathyroid Carcinoma. * **Side Effects:** The most common side effect is **hypocalcemia** (since it lowers PTH) and GI upset (nausea/vomiting). * **Etelcalcetide:** A newer intravenous calcimimetic that also targets the CaSR. * **Key Distinction:** Unlike Vitamin D analogs, Cinacalcet lowers PTH without increasing intestinal absorption of calcium and phosphorus, making it ideal for patients with high calcium-phosphorus products.

Q: All of the following are true regarding adverse effects of chlorpropamide except?

Less incidence of hypoglycemia. **Explanation:** Chlorpropamide is a **first-generation sulfonylurea** used in the management of Type 2 Diabetes Mellitus. Understanding its unique pharmacokinetic profile is key to identifying its adverse effects. **Why Option B is the Correct Answer:** Chlorpropamide has an exceptionally **long half-life (approx. 32–36 hours)** and is excreted slowly by the kidneys. Because of its prolonged duration of action, it actually carries a **higher incidence of severe and prolonged hypoglycemia** compared to other sulfonylureas, especially in elderly patients or those with renal impairment. Therefore, the statement "Less incidence of hypoglycemia" is false. **Analysis of Other Options:** * **A. Releases ADH:** Chlorpropamide is unique among sulfonylureas because it increases the secretion of Antidiuretic Hormone (ADH) and enhances the sensitivity of renal tubules to ADH. This can lead to **SIADH** and **dilutional hyponatremia**. * **C. More incidence of weight gain:** Like all sulfonylureas, chlorpropamide stimulates insulin release. Insulin is an anabolic hormone that promotes lipogenesis, leading to weight gain as a common side effect. * **D. Disulfiram-like reaction:** Chlorpropamide can inhibit aldehyde dehydrogenase. If a patient consumes alcohol while on this medication, they may experience flushing, nausea, and tachycardia (the **Disulfiram-like reaction**). **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for DI?** Chlorpropamide was historically used in **Partial Central Diabetes Insipidus** due to its ADH-potentiating effect. * **The "C" Rule:** Remember **C**hlorpropamide causes **C**onfusion (due to hyponatremia), **C**holestatic jaundice, and **C**hlorpropamide-alcohol flush. * **Avoid in Elderly:** Due to the high risk of prolonged hypoglycemia and hyponatremia, it is generally avoided in geriatric populations (Beers Criteria).

Question 1

What is a known effect of steroids?

Accepted Answer

Prevent de-iodination

Answer

Increase TSH

Answer

Increased FSH

Answer

All of the above

Question 2

Exenatide is prescribed for which disease?

Accepted Answer

Diabetes

Answer

Osteoporosis

Answer

Hyperthyroidism

Answer

Infertility

Question 3

An elderly male patient has benign prostatic hyperplasia. Which of the following medications can be used to suppress prostatic growth?

Accepted Answer

Finasteride

Answer

Spironolactone

Answer

Ketoconazole

Answer

Flutamide

Question 4

All of the following drugs cause hyperprolactinemia EXCEPT:

Accepted Answer

Bromocriptine

Answer

Haloperidol

Answer

Chlorpromazine

Answer

Metoclopramide

Question 5

Which of the following is a GLP-1 analogue used in the management of diabetes mellitus?

Accepted Answer

Exenatide

Answer

Pramalintide

Answer

Sitagliptin

Answer

Canagliflozin

Question 6

Which of the following is a long-acting insulin?

Accepted Answer

Detemir

Answer

Lispro

Answer

Aspart

Answer

Glulisine

Question 7

Mechanism of action of sildenafil is:

Accepted Answer

Phosphodiesterase-5 inhibitor

Answer

5 alpha reductase inhibitor

Answer

Antiandrogen

Answer

Androgenic

Question 8

Which of the following is used to treat Laron's dwarfism?

Accepted Answer

Mecasermin

Answer

Sermorelin

Answer

Tesamorelin

Answer

Ganirelix

Question 9

Cinacalcet acts by which of the following mechanisms?

Accepted Answer

Decreasing parathyroid hormone secretion

Answer

Inhibiting RANK-ligand

Answer

Activating osteoblasts

Answer

Increasing vitamin D levels

Question 10

All of the following are true regarding adverse effects of chlorpropamide except?

Accepted Answer

Less incidence of hypoglycemia

Answer

Releases ADH

Answer

More incidence of weight gain

Answer

Disulfiram like reaction may occur

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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