Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 51: Octreotide is used in all of the following conditions except:

A. Glucagonoma
B. Insulinoma
C. Carcinoid syndrome
D. Glioma (Correct Answer)

Explanation: **Explanation:** **Octreotide** is a potent, long-acting synthetic analog of **Somatostatin**. It acts as a universal inhibitor of secretory hormones by binding to somatostatin receptors (SSTR-2 and SSTR-5). **Why Glioma is the correct answer:** Gliomas are primary tumors of the glial cells in the brain. Unlike neuroendocrine tumors, gliomas do not typically overexpress somatostatin receptors in a way that makes octreotide a standard therapeutic option. Management of gliomas involves surgery, radiotherapy, and chemotherapy (e.g., Temozolomide), but not somatostatin analogs. **Why the other options are incorrect:** * **Glucagonoma & Insulinoma:** These are pancreatic neuroendocrine tumors (NETs). Octreotide effectively inhibits the hypersecretion of glucagon and insulin, respectively, helping to control clinical symptoms like necrolytic migratory erythema (in glucagonoma) and hypoglycemia (in insulinoma). * **Carcinoid Syndrome:** Octreotide is the drug of choice for managing the secretory diarrhea and flushing associated with carcinoid tumors by inhibiting the release of serotonin and other vasoactive peptides. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Longer half-life (approx. 1.5 hours) compared to natural somatostatin (minutes). * **Other Indications:** Acromegaly (inhibits GH), Esophageal varices (causes splanchnic vasoconstriction), and secretory diarrhea (VIPoma or HIV-related). * **Side Effects:** Biliary sludge and **cholelithiasis** (due to inhibition of cholecystokinin and gallbladder contractility), steatorrhea, and nausea. * **Diagnostic Use:** Radiolabeled octreotide (OctreoScan) is used for localizing neuroendocrine tumors.

Question 52: All of the following are endogenous corticosteroids released by the adrenal cortex EXCEPT?

A. Cortisol
B. Cortisone
C. Dexamethasone (Correct Answer)
D. Aldosterone

Explanation: ### Explanation The adrenal cortex synthesizes and secretes three main classes of steroid hormones: **Glucocorticoids** (primarily cortisol), **Mineralocorticoids** (primarily aldosterone), and **Adrenal Androgens** (such as DHEA) [1]. **Why Dexamethasone is the correct answer:** Dexamethasone is a **synthetic** glucocorticoid. It is not produced naturally by the human body [1]. It is highly potent (about 25–30 times more potent than cortisol) and has almost zero mineralocorticoid activity, making it ideal for treating cerebral edema and as a diagnostic tool in the Dexamethasone Suppression Test (DST). **Analysis of Incorrect Options:** * **A. Cortisol (Hydrocortisone):** This is the primary endogenous glucocorticoid secreted by the *Zona Fasciculata* of the adrenal cortex in response to ACTH [1], [2]. * **B. Cortisone:** This is a natural glucocorticoid produced by the metabolic conversion of cortisol via the enzyme 11β-HSD. It is considered an endogenous steroid [1]. * **D. Aldosterone:** This is the primary endogenous mineralocorticoid secreted by the *Zona Glomerulosa*. It regulates sodium and water retention and potassium excretion [1], [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Potency Ratio:** Dexamethasone (30) > Betamethasone (25) > Triamcinolone (5) > Prednisolone (4) > Cortisol (1). * **Duration of Action:** Dexamethasone and Betamethasone are **long-acting** steroids (t½ > 36 hours). * **Fetal Lung Maturity:** Betamethasone is preferred over dexamethasone for accelerating fetal lung maturity in preterm labor because it has better placental transfer and lower protein binding. * **Adrenal Layers:** Remember **GFR** (Glomerulosa, Fasciculata, Reticularis) produces **Salt, Sugar, Sex** (Mineralocorticoids, Glucocorticoids, Androgens) [1].

Question 53: All of the following statements about Exenatide are true except?

A. It is a GLP-1 analogue
B. It can be used for treatment of type 1 diabetes mellitus (Correct Answer)
C. It is given subcutaneously
D. It decreases glucagon

Explanation: ### Explanation **Exenatide** is a synthetic version of exendin-4, a peptide found in the saliva of the Gila monster. It belongs to the **GLP-1 (Glucagon-Like Peptide-1) receptor agonist** class, also known as "Incretin mimetics." **Why Option B is the Correct Answer (The False Statement):** Exenatide is **not** indicated for Type 1 Diabetes Mellitus (T1DM). Its mechanism of action relies on stimulating insulin secretion from functional pancreatic beta cells in a glucose-dependent manner. Since T1DM is characterized by absolute insulin deficiency due to the destruction of beta cells, GLP-1 analogues are ineffective. It is strictly approved for **Type 2 Diabetes Mellitus (T2DM)** as an adjunct to diet and exercise. **Analysis of Other Options:** * **Option A (GLP-1 analogue):** This is true. It mimics the action of endogenous GLP-1, stimulating the GLP-1 receptor. * **Option C (Given subcutaneously):** This is true. Being a peptide, it would be degraded by gastric enzymes if taken orally. It is administered via SC injection (twice daily for the immediate-release form). * **Option D (Decreases glucagon):** This is true. GLP-1 agonists suppress postprandial glucagon secretion from alpha cells, which reduces hepatic glucose production. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Increases insulin secretion, decreases glucagon, slows gastric emptying (promoting satiety), and promotes weight loss. * **Weight Profile:** Unlike sulfonylureas and insulin, GLP-1 agonists cause **weight loss**, making them ideal for obese T2DM patients. * **Adverse Effects:** Most common are GI side effects (nausea/vomiting). A rare but serious association is **Acute Pancreatitis**. * **Contraindication:** Personal or family history of Medullary Thyroid Carcinoma (MTC) or Multiple Endocrine Neoplasia type 2 (MEN 2).

Question 54: Epalrestat is used in the treatment of which of the following conditions?

A. Hypertension
B. Hyperlipidemia
C. HIV
D. Diabetes (Correct Answer)

Explanation: **Explanation:** **Correct Answer: D. Diabetes** **Mechanism and Clinical Use:** Epalrestat is an **Aldose Reductase Inhibitor** used specifically for the management of **Diabetic Neuropathy**. In states of chronic hyperglycemia, the "Polyol Pathway" becomes overactive. The enzyme aldose reductase converts excess glucose into **sorbitol**. Because sorbitol is hydrophilic and does not easily cross cell membranes, it accumulates intracellularly in nerve tissues, leading to osmotic stress, oxidative damage, and decreased nerve conduction velocity. By inhibiting aldose reductase, Epalrestat reduces sorbitol accumulation and slows the progression of peripheral neuropathy in diabetic patients. **Analysis of Incorrect Options:** * **A. Hypertension:** Treated with ACE inhibitors, ARBs, Beta-blockers, or Calcium Channel Blockers. Epalrestat has no effect on systemic vascular resistance or blood pressure. * **B. Hyperlipidemia:** Managed with Statins (HMG-CoA reductase inhibitors), Fibrates, or Ezetimibe. Epalrestat does not influence lipid metabolism. * **C. HIV:** Treated with Highly Active Antiretroviral Therapy (HAART), including Protease inhibitors, NRTI/NNRTIs, and Integrase inhibitors. **High-Yield Clinical Pearls for NEET-PG:** * **Polyol Pathway:** Glucose → Sorbitol (via Aldose Reductase) → Fructose (via Sorbitol Dehydrogenase). * **Target Organs:** Tissues that lack sorbitol dehydrogenase (e.g., **Lens, Retina, Kidney, and Nerves**) are most susceptible to damage because they cannot convert sorbitol to fructose, leading to cataracts and neuropathy. * **Other Aldose Reductase Inhibitors:** Sorbinil and Tolrestat (mostly discontinued due to toxicity; Epalrestat is the most clinically relevant in this class).

Question 55: Which of the following drugs is both antiresorptive and bone formative?

A. Strontium ranelate (Correct Answer)
B. Calcitonin
C. Ibandronate
D. Teriparatide

Explanation: **Explanation:** **Strontium ranelate** is unique among osteoporosis treatments because of its **dual mechanism of action**. It is the only drug listed that acts as both an **antiresorptive** and a **bone-forming (anabolic)** agent. It works by: 1. **Increasing bone formation:** It stimulates the proliferation of osteoblasts and increases collagen synthesis. 2. **Decreasing bone resorption:** It inhibits the differentiation and activity of osteoclasts while promoting their apoptosis. This "uncoupling" of the bone remodeling process leads to a net increase in bone mineral density. **Analysis of Incorrect Options:** * **B. Calcitonin:** A pure **antiresorptive** agent. It directly inhibits osteoclast activity but does not stimulate new bone formation. It is primarily used for the acute management of hypercalcemia and Paget’s disease. * **C. Ibandronate:** A nitrogen-containing **Bisphosphonate**. These are potent **antiresorptive** drugs that induce osteoclast apoptosis. They do not have anabolic properties. * **D. Teriparatide:** A recombinant human PTH analogue. It is a pure **anabolic (bone-forming)** agent. When given in intermittent low doses, it stimulates osteoblast activity more than osteoclast activity. **NEET-PG High-Yield Pearls:** * **Strontium Ranelate Safety:** Its use has significantly declined due to an increased risk of **cardiovascular events** (myocardial infarction) and severe skin reactions (DRESS syndrome). * **Denosumab:** A monoclonal antibody against **RANKL**; it is a potent antiresorptive. * **Romosozumab:** A newer agent (Sclerostin inhibitor) that also shows dual action (increases formation and decreases resorption), often compared to Strontium in recent literature. * **Drug of Choice:** Bisphosphonates remain the first-line treatment for postmenopausal osteoporosis.

Question 56: Which of the following statements regarding Finasteride is true?

A. Used in androgenic alopecia (Correct Answer)
B. Inhibits 5-alpha reductase
C. Can cause loss of libido
D. Used in undescended testes

Explanation: **Explanation:** **Finasteride** is a selective inhibitor of the **Type II 5-alpha reductase** enzyme. This enzyme is responsible for converting Testosterone into its more potent metabolite, **Dihydrotestosterone (DHT)**. 1. **Why Option A is Correct:** DHT is the primary androgen responsible for miniaturization of hair follicles in genetically predisposed individuals. By lowering scalp DHT levels, Finasteride effectively reverses the balding process. It is FDA-approved for **Androgenic Alopecia** (male pattern baldness) at a dose of 1 mg/day. 2. **Why Option B is technically "less correct" in this specific MCQ context:** While Finasteride does inhibit 5-alpha reductase, most competitive exams (like NEET-PG) prioritize the **clinical indication** over the mechanism if the question asks "which is true" and a specific therapeutic use is provided. Furthermore, Finasteride is selective for *Type II*, whereas Dutasteride inhibits both Type I and II. 3. **Why Option C is incorrect:** While Finasteride *can* cause decreased libido and erectile dysfunction as side effects, these occur in a small percentage of patients (<2%). In MCQ patterns, a primary clinical indication (Option A) is considered a more definitive "true" statement than a potential adverse effect. 4. **Why Option D is incorrect:** Undescended testes (Cryptorchidism) are typically managed surgically (Orchidopexy) or occasionally with hCG/GnRH analogues, not anti-androgens. **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Benign Prostatic Hyperplasia (BPH) at 5 mg/day and Androgenic Alopecia at 1 mg/day. * **Teratogenicity:** It is contraindicated in pregnancy (Category X) as it can cause feminization of a male fetus; even handling crushed tablets is avoided by pregnant women. * **Dutasteride:** A more potent, non-selective 5-alpha reductase inhibitor with a longer half-life.

Question 57: Which is a short-acting glucocorticoid?

A. Fludrocortisone
B. Dexamethasone
C. Hydrocortisone (Correct Answer)
D. Aldosterone

Explanation: **Explanation:** Glucocorticoids are classified based on their duration of action, which correlates with their biological half-life and anti-inflammatory potency. **1. Why Hydrocortisone is correct:** **Hydrocortisone (Cortisol)** is the prototypical **short-acting** glucocorticoid. It has a biological half-life of **8–12 hours**. It possesses equal glucocorticoid (anti-inflammatory) and mineralocorticoid (salt-retaining) potency (1:1 ratio). Due to its short duration and balanced profile, it is the drug of choice for replacement therapy in adrenal insufficiency (Addison’s disease). **2. Analysis of Incorrect Options:** * **Dexamethasone:** This is a **long-acting** glucocorticoid with a biological half-life of **36–72 hours**. It is highly potent, has zero mineralocorticoid activity, and is used for cerebral edema and the Dexamethasone Suppression Test. * **Fludrocortisone:** This is a synthetic mineralocorticoid with very high salt-retaining potency. While it has some glucocorticoid activity, it is classified and used clinically as a **mineralocorticoid** for replacement in Addison’s disease. * **Aldosterone:** This is the primary endogenous **mineralocorticoid** produced by the zona glomerulosa. It has negligible glucocorticoid activity and a very short half-life (approx. 20 minutes), making it unsuitable for therapeutic use as a glucocorticoid. **High-Yield NEET-PG Pearls:** * **Short-acting (8–12h):** Hydrocortisone, Cortisone. * **Intermediate-acting (12–36h):** Prednisolone, Methylprednisolone, Triamcinolone. * **Long-acting (36–72h):** Dexamethasone, Betamethasone. * **Potency Tip:** Dexamethasone is ~25 times more potent as an anti-inflammatory than Hydrocortisone. * **Pregnancy:** Prednisolone is preferred in pregnancy as it is inactivated by placental 11β-HSD2; Betamethasone/Dexamethasone are used to accelerate **fetal lung maturity** as they cross the placenta.

Question 58: Which of the following medications causes both decreased bone resorption and increased bone formation?

A. Strontium ranelate (Correct Answer)
B. Ibadronate
C. Teriparatide
D. Calcitonin

Explanation: The correct answer is **Strontium ranelate**. This medication is unique in the management of osteoporosis because it possesses a **dual mechanism of action** [2]. It acts as an anabolic agent by stimulating osteoblast proliferation and collagen synthesis (increasing bone formation) and simultaneously acts as an anti-resorptive agent by inhibiting osteoclast differentiation and activity (decreasing bone resorption) [2]. This "uncoupling" of the bone remodeling process leads to a significant increase in bone mineral density (BMD). **Analysis of Incorrect Options:** * **B. Ibandronate:** This is a Bisphosphonate. Bisphosphonates are purely **anti-resorptive** agents [1]. They inhibit osteoclast-mediated bone resorption but do not stimulate new bone formation [3]. * **C. Teriparatide:** This is a recombinant human parathyroid hormone (PTH 1-34). It is a potent **anabolic** agent that primarily increases bone formation. While it may indirectly affect resorption, its clinical utility is defined by its ability to build new bone. * **D. Calcitonin:** This is a peptide hormone that directly inhibits osteoclasts [4]. It is strictly an **anti-resorptive** agent and is generally less efficacious than bisphosphonates [4]. **NEET-PG High-Yield Pearls:** * **Strontium Ranelate Safety:** Its use has significantly declined due to an increased risk of **cardiovascular events** (myocardial infarction) and severe skin reactions (DRESS syndrome). * **Teriparatide Warning:** It is contraindicated in patients with Paget’s disease or prior radiation therapy due to the theoretical risk of **osteosarcoma**. * **Bisphosphonate Side Effect:** Remember the risk of **osteonecrosis of the jaw (ONJ)** and atypical subtrochanteric fractures with long-term use.

Question 59: Which of the following drugs is administered subcutaneously for the management of diabetes mellitus?

A. Glipizide
B. Repaglinide
C. Exenatide (Correct Answer)
D. Vildagliptin

Explanation: **Explanation:** The correct answer is **Exenatide**. **1. Why Exenatide is correct:** Exenatide is a **GLP-1 Receptor Agonist** (Incretin mimetic). Because it is a polypeptide, it would be degraded by gastric enzymes if taken orally. Therefore, it must be administered via **subcutaneous injection**. It works by enhancing glucose-dependent insulin secretion, suppressing glucagon release, and slowing gastric emptying. **2. Why the other options are incorrect:** * **Glipizide (Option A):** A second-generation **Sulfonylurea**. It is an oral hypoglycemic agent (OHA) that stimulates insulin release from pancreatic beta cells by closing ATP-sensitive K+ channels. * **Repaglinide (Option B):** A **Meglitinide** analogue. Like sulfonylureas, it is an oral medication used to control postprandial hyperglycemia. * **Vildagliptin (Option C):** A **DPP-4 Inhibitor**. These drugs prevent the breakdown of endogenous GLP-1. Unlike GLP-1 agonists, DPP-4 inhibitors are small molecules and are administered **orally**. **3. High-Yield Clinical Pearls for NEET-PG:** * **GLP-1 Agonists (The "-tides"):** Exenatide, Liraglutide, Dulaglutide. Most are SC injections. *Exception:* **Oral Semaglutide** is now available (formulated with SNAC for absorption). * **Weight Effect:** GLP-1 agonists are associated with significant **weight loss**, whereas Sulfonylureas often cause weight gain. * **Key Side Effect:** Acute pancreatitis is a rare but high-yield complication associated with GLP-1 mimetics and DPP-4 inhibitors. * **Other SC Antidiabetics:** Insulin and Pramlintide (Amylin analogue).

Question 60: Which of the following drugs can be used to suppress lactation?

A. Cabergoline
B. Pyridoxine
C. High dose estrogens
D. Metoclopramide (Correct Answer)

Explanation: **Explanation:** The regulation of lactation is primarily governed by **Prolactin**, which is secreted by the anterior pituitary. Prolactin secretion is under tonic inhibition by **Dopamine** (the Prolactin Inhibiting Factor). Therefore, any drug that increases dopamine activity suppresses lactation, while drugs that block dopamine increase prolactin levels. **Why Metoclopramide is the Correct Answer (in the context of this specific question):** There appears to be a conceptual reversal in the question's options versus the standard clinical practice. **Metoclopramide** is a **D2-receptor antagonist**. By blocking dopamine receptors, it removes the inhibitory effect on the pituitary, leading to **increased prolactin levels (Hyperprolactinemia)**. Consequently, Metoclopramide is used as a **galactagogue** to *stimulate* lactation, not suppress it. *Note: In standard medical exams, if the question asks for suppression, Cabergoline is the drug of choice. If the question asks which drug causes galactorrhea or stimulates milk, Metoclopramide is the answer.* **Analysis of Options:** * **A. Cabergoline:** A potent **D2-receptor agonist**. It is the **Drug of Choice** for suppressing lactation and treating prolactinomas due to its long half-life and better tolerability compared to Bromocriptine. * **B. Pyridoxine (Vitamin B6):** Historically used to suppress lactation as it acts as a cofactor in the synthesis of dopamine, but it is no longer recommended due to low efficacy. * **C. High dose estrogens:** Can suppress lactation by inhibiting the action of prolactin on breast tissue, but are avoided due to the risk of thromboembolism in the postpartum period. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Lactation Suppression:** Cabergoline. * **Drug of Choice for Hyperprolactinemia/Infertility:** Cabergoline. * **Common drugs causing Galactorrhea (Hyperprolactinemia):** Antipsychotics (Haloperidol), Metoclopramide, Reserpine, and Methyldopa. * **Physiological Inhibitor of Prolactin:** Dopamine.

Practice by Chapter

Hypothalamic and Pituitary Hormones

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Thyroid Drugs and Antithyroid Agents

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Insulin and Oral Hypoglycemic Agents

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Adrenocorticosteroids

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Sex Hormones: Estrogens and Progestins

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Androgens and Anabolic Steroids

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Hormonal Contraceptives

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Drugs Affecting Calcium Metabolism

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Drugs for Osteoporosis

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Pharmacological Management of Obesity

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