Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 481: Glucocorticoids act in inflammation mainly by which mechanism?

A. Decreasing lipocortin
B. Increasing IL-2
C. Increasing lipocortin (Correct Answer)
D. Increasing CRP

Explanation: **Explanation:**Glucocorticoids exert their potent anti-inflammatory effects primarily through the modulation of gene transcription [2]. The correct answer is **Increasing lipocortin** (also known as Annexin A1).**Mechanism of Action:**Glucocorticoids bind to cytosolic glucocorticoid receptors, which then translocate to the nucleus. This leads to the **upregulation (induction)** of **Lipocortin-1** (also known as Annexin A1). Lipocortin acts as a potent inhibitor of the enzyme **Phospholipase A2 (PLA2)**. Since PLA2 is responsible for releasing arachidonic acid from membrane phospholipids, its inhibition prevents the synthesis of all downstream inflammatory mediators, including prostaglandins, leukotrienes, and platelet-activating factor (PAF) [1].**Analysis of Incorrect Options:** * **A. Decreasing lipocortin:** This is the opposite of the actual mechanism. Decreasing lipocortin would promote inflammation. * **B. Increasing IL-2:** Glucocorticoids actually **decrease** the production of pro-inflammatory cytokines like IL-1, IL-2, IL-6, and TNF-α by inhibiting the transcription factor **NF-κB** [1]. * **D. Increasing CRP:** C-reactive protein (CRP) is an acute-phase reactant produced during inflammation. Glucocorticoids **decrease** CRP levels as they suppress the overall inflammatory response.**High-Yield Clinical Pearls for NEET-PG:** * **Genomic vs. Non-genomic:** Most effects are genomic (taking hours), but rapid effects occur via non-genomic pathways [1]. * **NF-κB Inhibition:** This is a high-yield concept; glucocorticoids "switch off" inflammatory genes by inhibiting NF-κB [1]. * **Hematological effects:** They cause **lymphocytopenia, eosinopenia, and monocytopenia**, but lead to **neutrophilia** (due to decreased margination). * **Metabolic hallmark:** They are catabolic in nature (except in the liver), leading to muscle wasting and osteoporosis, but promote gluconeogenesis.

Question 482: Which of the following is true of biguanides?

A. Cause little or no hypoglycemia (Correct Answer)
B. Stimulates pancreatic beta cells
C. Completely metabolized
D. Promotes hepatic gluconeogenesis

Explanation: **Explanation:** Biguanides, primarily **Metformin**, are the first-line pharmacological agents for Type 2 Diabetes Mellitus. Their primary mechanism of action is the activation of **AMP-activated protein kinase (AMPK)**, which leads to increased insulin sensitivity and decreased hepatic glucose production. **1. Why Option A is correct:** Metformin is classified as an **"euglycemic"** agent rather than a hypoglycemic one. Unlike sulfonylureas, it does not stimulate insulin secretion from the pancreas. Instead, it works by improving the utilization of existing insulin and suppressing glucose production. Therefore, when used as monotherapy, it carries a negligible risk of hypoglycemia. **2. Why the other options are incorrect:** * **Option B:** Stimulating pancreatic beta cells is the mechanism of **Sulfonylureas** and **Meglitinides**. Metformin’s action is independent of beta-cell function. * **Option C:** Metformin is **not metabolized** in the body. It is excreted unchanged by the kidneys via tubular secretion. This is why it is contraindicated in renal failure (CrCl < 30 ml/min) due to the risk of accumulation. * **Option D:** Metformin **inhibits** hepatic gluconeogenesis (the synthesis of glucose from non-carbohydrate sources) and glycogenolysis, thereby lowering fasting blood glucose levels. **NEET-PG High-Yield Pearls:** * **Side Effects:** The most common side effects are GI-related (diarrhea, abdominal pain). The most serious, though rare, is **Lactic Acidosis**. * **Weight Neutrality:** Metformin is often associated with modest weight loss, making it ideal for obese diabetic patients. * **Vitamin Deficiency:** Long-term use can lead to **Vitamin B12 deficiency** due to interference with its absorption in the terminal ileum. * **Other Uses:** It is also used in Polycystic Ovarian Syndrome (PCOS) to improve insulin resistance and induce ovulation.

Question 483: Alendronate acts by:

A. Inhibiting osteoclasts (Correct Answer)
B. Inhibiting osteoblasts
C. Inhibiting both osteoclasts and osteoblasts
D. None of the above

Explanation: **Mechanism of Action** Alendronate is a **Bisphosphonate**, a class of drugs that are structural analogs of pyrophosphate. These drugs have a high affinity for hydroxyapatite crystals in the bone. When osteoclasts begin to resorb bone, they ingest the bisphosphonates. Once inside the cell, Alendronate inhibits the enzyme **Farnesyl Pyrophosphate (FPP) Synthase** in the mevalonate pathway. This prevents the prenylation of GTP-binding proteins (like Rho, Rac, and Rab) essential for osteoclast function, leading to the loss of the "ruffled border," inactivation, and eventually **apoptosis of osteoclasts**. **Analysis of Options** * **Option A (Correct):** By inducing osteoclast apoptosis and decreasing their bone-resorbing activity, Alendronate effectively increases bone mineral density. * **Option B & C (Incorrect):** Alendronate does not inhibit osteoblasts. In fact, by reducing bone resorption, it indirectly allows osteoblastic bone formation to exceed resorption in the short term, though long-term use leads to a coupled decrease in overall bone turnover. **NEET-PG High-Yield Pearls** * **Administration:** Must be taken on an empty stomach with a full glass of water, and the patient must remain upright for 30 minutes to prevent **erosive esophagitis**. * **Side Effects:** Atypical femur fractures and **Osteonecrosis of the Jaw (ONJ)** are rare but high-yield complications associated with long-term use. * **Drug of Choice:** Bisphosphonates are the first-line treatment for **Postmenopausal Osteoporosis** and **Paget’s disease**. * **Potency:** Alendronate is a second-generation (nitrogen-containing) bisphosphonate, which is significantly more potent than first-generation agents like Etidronate.

Question 484: In which of the following diseases are corticosteroids indicated?

A. Osteoporosis
B. Peptic ulcer
C. Collagen vascular diseases (Correct Answer)
D. Tuberculosis

Explanation: **Explanation:** **1. Why Collagen Vascular Diseases is Correct:** Corticosteroids are potent anti-inflammatory and immunosuppressive agents. They work by inhibiting phospholipase A2 (decreasing prostaglandins and leukotrienes) and suppressing the activation of T-cells and macrophages. **Collagen vascular diseases** (e.g., Systemic Lupus Erythematosus, Polyarteritis Nodosa, Dermatomyositis) are autoimmune conditions characterized by systemic inflammation. Steroids are the mainstay of treatment here to induce remission and prevent organ damage. **2. Why the Other Options are Incorrect:** * **Osteoporosis:** Corticosteroids are a major *cause* of secondary osteoporosis. They inhibit osteoblast activity, decrease intestinal calcium absorption, and increase renal calcium excretion. * **Peptic Ulcer:** Steroids are generally contraindicated or used with extreme caution in peptic ulcer disease. They inhibit protective prostaglandins in the gastric mucosa and can mask the symptoms of perforation, leading to "silent peritonitis." * **Tuberculosis (TB):** Since steroids suppress the immune system, they can lead to the reactivation of latent TB or worsen an active infection. They are only used in specific TB cases (like TB meningitis or pericarditis) alongside strict antitubercular therapy (ATT) to reduce inflammatory complications. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Steroids are the DOC for acute exacerbations of bronchial asthma and replacement therapy in Addison’s disease. * **Side Effect Profile:** Remember the mnemonic **CUSHINGOID** (Cataracts, Ulcers, Skin thinning, Hypertension/Hirsutism, Immunosuppression, Necrosis of femoral head, Glucose elevation, Osteoporosis, Impaired wound healing, Depression/Psychosis). * **Withdrawal:** Long-term steroid therapy must never be stopped abruptly due to the risk of **Acute Adrenal Insufficiency** (secondary to HPA axis suppression).

Question 485: What is the best management for hypoglycemia in a girl child with Congenital adrenal hyperplasia?

A. Betamethasone
B. Beclomethasone
C. Budesonide
D. Hydrocortisone (Correct Answer)

Explanation: Explanation: **1. Why Hydrocortisone is the Correct Choice:** Congenital Adrenal Hyperplasia (CAH), most commonly due to 21-hydroxylase deficiency, results in impaired cortisol synthesis. Cortisol is a vital counter-regulatory hormone that maintains blood glucose levels via gluconeogenesis. [3] Its deficiency leads to life-threatening hypoglycemia and adrenal crisis. **Hydrocortisone** is the drug of choice for replacement therapy in children because: * **Physiological Match:** It is the synthetic equivalent of endogenous cortisol. * **Balanced Activity:** It possesses both glucocorticoid and significant mineralocorticoid activity (essential for salt-wasting CAH). [1] * **Growth Profile:** It has a short half-life and lower potency compared to synthetic steroids, making it less likely to cause growth suppression or iatrogenic Cushing’s syndrome in a developing child. **2. Why Other Options are Incorrect:** * **Betamethasone (A):** This is a long-acting, highly potent systemic steroid. It lacks mineralocorticoid activity and is associated with severe growth retardation in children. [4] It is primarily used for fetal lung maturity. * **Beclomethasone (B) & Budesonide (C):** These are primarily "topical" steroids used via inhalation (Asthma) or intranasal routes (Rhinitis). They have high first-pass metabolism and low systemic bioavailability, making them ineffective for treating systemic adrenal insufficiency or acute hypoglycemia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (Adults):** While Hydrocortisone is preferred in children, longer-acting agents like Prednisolone or Dexamethasone may be used in adults to improve compliance. [2] * **Monitoring:** Therapy in CAH is monitored by measuring levels of **17-hydroxyprogesterone** and androstenedione. [3] * **Stress Dosing:** During periods of infection, trauma, or surgery, the dose of Hydrocortisone must be doubled or tripled ("Stress doses") to prevent adrenal crisis. [5] * **Mineralocorticoid:** In the salt-wasting variety, **Fludrocortisone** is added to the regimen. [3]

Question 486: Which of the following drugs is used to control tachycardia and palpitations in persons with acute symptoms of hyperthyroidism?

A. Liothyronine
B. Propranolol (Correct Answer)
C. Methimazole
D. Potassium iodide

Explanation: ### Explanation **Correct Answer: B. Propranolol** **Mechanism and Rationale:** Hyperthyroidism leads to an "over-sensitization" of beta-adrenergic receptors to catecholamines. This manifests as sympathetic overactivity, including tachycardia, palpitations, tremors, and anxiety. **Propranolol**, a non-selective beta-blocker, is the drug of choice for the **immediate symptomatic relief** of these thyrotoxic symptoms. Beyond blocking cardiac beta-1 receptors, Propranolol has a unique advantage in hyperthyroidism: at high doses, it **inhibits the peripheral conversion of T4 (thyroxine) to the more active T3 (triiodothyronine)** by inhibiting the enzyme 5'-deiodinase. This dual action makes it superior to other beta-blockers in managing thyrotoxicosis and thyroid storm. **Analysis of Incorrect Options:** * **A. Liothyronine:** This is synthetic T3. Administering it would worsen hyperthyroid symptoms and potentially trigger a thyroid storm. * **C. Methimazole:** This is an anti-thyroid drug (thioamide) that inhibits thyroid hormone *synthesis* by blocking thyroid peroxidase. While it treats the underlying cause, it has a slow onset of action (weeks) and does not provide immediate relief for acute sympathetic symptoms. * **D. Potassium iodide:** This inhibits the *release* of thyroid hormones (Wolff-Chaikoff effect). It is used pre-operatively or in thyroid storm to rapidly decrease hormone levels, but it does not directly control the heart rate or palpitations. **NEET-PG High-Yield Pearls:** * **Drug of Choice for Thyroid Storm:** IV Propranolol (for symptoms) + PTU (Propylthiouracil is preferred over Methimazole here as it also inhibits T4 to T3 conversion). * **Alternative for Asthmatics:** If a patient has hyperthyroidism and asthma (where Propranolol is contraindicated), use **Diltiazem** (Calcium Channel Blocker) to control the heart rate. * **Pre-operative use:** Lugol’s iodine is given 10 days before thyroid surgery to decrease the vascularity and size of the gland.

Question 487: Which of the following drug formulations is known to be hepatotoxic?

A. Transdermal testosterone patch
B. 17 alpha methyl testosterone (Correct Answer)
C. Intranasal testosterone
D. Injectable testosterone undecanoate

Explanation: **Explanation:** The correct answer is **17 alpha methyl testosterone**. **1. Why 17 alpha methyl testosterone is Hepatotoxic:** Testosterone, in its natural form, undergoes rapid first-pass metabolism in the liver, making it ineffective when taken orally. To overcome this, the molecule is modified by adding an alkyl group at the C-17 position (17-α alkylation). While this modification makes the drug orally bioavailable, it significantly increases the risk of **cholestatic jaundice** and serious liver conditions like **peliosis hepatis** (blood-filled cysts in the liver) and hepatic adenomas. **2. Why other options are incorrect:** * **Transdermal patches (A) and Intranasal (C):** These routes bypass the first-pass metabolism of the liver. They deliver testosterone directly into the systemic circulation, avoiding the high hepatic concentrations associated with oral alkylated steroids. * **Injectable Testosterone Undecanoate (D):** This is a testosterone ester. Esters are typically administered intramuscularly in an oil base. They are slowly released into the blood and hydrolyzed to natural testosterone, which does not possess the hepatotoxic profile of 17-α alkylated derivatives. **3. NEET-PG High-Yield Pearls:** * **Hepatotoxicity Rule:** Always associate **17-α alkylated steroids** (e.g., Methyltestosterone, Oxandrolone, Danazol, Stanozolol) with liver toxicity. * **Peliosis Hepatis:** A classic "buzzword" for complications arising from long-term anabolic steroid use. * **Clinical Use:** Due to hepatotoxicity, methyltestosterone is rarely used in modern clinical practice, replaced by safer transdermal or injectable esters. * **Side Effects:** Beyond hepatotoxicity, watch for erythrocytosis (increased hematocrit), azoospermia, and premature epiphyseal closure in children.

Question 488: All of the following are advantages of using Raloxifene over estrogen in postmenopausal women except?

A. Reduces fracture rates
B. Avoids endometrial hyperplasia
C. Reduces the incidence of venous thrombosis (Correct Answer)
D. No increase in the incidence of breast carcinoma

Explanation: **Explanation:** The correct answer is **C (Reduces the incidence of venous thrombosis)** because this is not an advantage; in fact, both Raloxifene and Estrogen share the same risk profile regarding coagulation. **1. Why Option C is the Correct Answer:** Raloxifene is a **Selective Estrogen Receptor Modulator (SERM)**. While it has tissue-specific effects, its effect on the liver is similar to estrogen, where it increases the synthesis of clotting factors. Consequently, Raloxifene **increases** the risk of **Deep Vein Thrombosis (DVT)** and pulmonary embolism, just like conventional Hormone Replacement Therapy (HRT). Therefore, it offers no advantage over estrogen in this specific category. **2. Why the other options are incorrect (Advantages of Raloxifene):** * **Option A (Reduces fracture rates):** Raloxifene acts as an **estrogen agonist in bone**, increasing bone mineral density and significantly reducing the risk of vertebral fractures in postmenopausal osteoporosis. * **Option B (Avoids endometrial hyperplasia):** Unlike estrogen, Raloxifene is an **estrogen antagonist in the uterus**. It does not cause endometrial proliferation, thus eliminating the need for progestin co-administration and reducing the risk of uterine cancer. * **Option D (No increase in breast carcinoma):** Raloxifene is an **estrogen antagonist in breast tissue**. It is actually FDA-approved for the prophylaxis of breast cancer in high-risk postmenopausal women. **High-Yield Clinical Pearls for NEET-PG:** * **Tamoxifen vs. Raloxifene:** Tamoxifen is an agonist at the uterus (risk of endometrial CA), whereas **Raloxifene is an antagonist at the uterus** (safe). Both are antagonists at the breast and agonists at the bone. * **Major Side Effect:** Hot flashes (due to antagonist effect in the CNS/hypothalamus). * **Contraindication:** History of venous thromboembolism (VTE). * **Key Distinction:** Raloxifene reduces **vertebral** fractures but has not been proven to reduce non-vertebral (hip) fractures as effectively as bisphosphonates.

Question 489: Which of the following statements about glipizide compared to chlorpropamide is true?

A. Glipizide is more potent than chlorpropamide. (Correct Answer)
B. Glipizide is longer acting than chlorpropamide.
C. Glipizide does not lower blood sugar in nondiabetic subjects, while chlorpropamide does.
D. Glipizide is less prone to cause a hypoglycemic reaction than chlorpropamide.

Explanation: **Explanation:** Sulfonylureas are classified into first and second generations. This question compares **Chlorpropamide** (1st generation) and **Glipizide** (2nd generation). **1. Why Option A is Correct:** Glipizide is a second-generation sulfonylurea. Second-generation agents are significantly **more potent** than first-generation agents on a milligram-to-milligram basis. While chlorpropamide is used in doses of 100–500 mg, glipizide is effective at much lower doses (5–20 mg). Potency refers to the amount of drug required to produce a specific effect, not the clinical efficacy. **2. Why the Other Options are Incorrect:** * **Option B:** Chlorpropamide is the **longest-acting** sulfonylurea (half-life ~32 hours; duration up to 60 hours). Glipizide has a short half-life (~3 hours) and a shorter duration of action, making it safer in elderly patients. * **Option C:** All sulfonylureas act by stimulating insulin release from pancreatic beta cells (via blocking $K_{ATP}$ channels). Therefore, they **all** lower blood sugar in both diabetic and non-diabetic subjects. * **Option D:** Because chlorpropamide has an exceptionally long duration of action and is excreted renally, it is actually **more prone** to causing prolonged, severe hypoglycemia, especially in the elderly or those with renal impairment. **High-Yield Clinical Pearls for NEET-PG:** * **Disulfiram-like reaction:** Most commonly associated with Chlorpropamide. * **SIADH/Dilutional Hyponatremia:** A unique side effect of Chlorpropamide (it increases ADH action). * **Glipizide:** Preferred in patients with mild renal impairment because it is primarily metabolized by the liver to inactive metabolites. * **Mechanism:** Sulfonylureas bind to the **SUR1 subunit** of the ATP-sensitive $K^+$ channel.

Question 490: What is the most common side effect of mifepristone?

A. Fever
B. Headache
C. Diarrhea (Correct Answer)
D. Rash

Explanation: **Explanation:** Mifepristone is a competitive progesterone receptor antagonist used primarily for medical termination of pregnancy (MTP) and the management of Cushing’s syndrome. **Why Diarrhea is the correct answer:** The most common side effects of mifepristone are gastrointestinal in nature. While mifepristone itself can cause nausea and vomiting, it is frequently administered in a regimen with **Misoprostol** (a PGE1 analog) for MTP. Misoprostol significantly increases intestinal motility and secretions, making **diarrhea** the most frequent and characteristic side effect reported by patients undergoing this treatment protocol. Even when used as monotherapy, GI upset remains the primary complaint. **Analysis of Incorrect Options:** * **A. Fever:** While a mild thermogenic effect or transient chills can occur (especially when combined with prostaglandins), it is less frequent than gastrointestinal symptoms. * **B. Headache:** This is a known side effect but occurs in a smaller percentage of patients compared to the nearly universal occurrence of GI distress. * **C. Rash:** Skin reactions are rare idiosyncratic responses and are not considered a common or expected side effect of the drug. **NEET-PG High-Yield Pearls:** * **Mechanism of Action:** Competitive antagonist at both Progesterone (PR) and Glucocorticoid (GR) receptors. * **MTP Protocol:** Usually 200 mg Mifepristone orally followed by 400–800 mcg Misoprostol (vaginal/sublingual/oral) 24–48 hours later. * **Other Uses:** Management of hyperglycemia in Cushing’s syndrome (due to GR antagonism) and as an emergency contraceptive. * **Contraindication:** Ectopic pregnancy (it is ineffective as it acts primarily on the decidua).

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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