Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 351: A patient with nephrotic syndrome on longstanding corticosteroid therapy may develop all the following except?

A. Hyperglycemia
B. Hypertrophy of muscle (Correct Answer)
C. Neuropsychiatric symptoms
D. Suppression of Hypothalamic pituitary adrenal axis

Explanation: ### Explanation **1. Why "Hypertrophy of muscle" is the correct answer:** Corticosteroids are **catabolic** in nature regarding peripheral tissues. They promote the breakdown of proteins into amino acids (proteolysis) to provide substrates for gluconeogenesis. This leads to **muscle wasting and atrophy** (myopathy), particularly affecting the proximal muscles of the limbs. Therefore, hypertrophy (muscle growth) is physiologically inconsistent with steroid therapy. **2. Analysis of Incorrect Options:** * **A. Hyperglycemia:** Glucocorticoids increase blood glucose levels by stimulating gluconeogenesis in the liver and decreasing peripheral glucose uptake (anti-insulin effect). This can lead to "Steroid-induced Diabetes." * **C. Neuropsychiatric symptoms:** Steroids can cross the blood-brain barrier and cause a wide range of behavioral changes, often referred to as "Steroid Psychosis." Symptoms include euphoria, insomnia, irritability, depression, or even frank psychosis. * **D. Suppression of HPA Axis:** Longstanding exogenous corticosteroid therapy provides negative feedback to the hypothalamus (CRH) and anterior pituitary (ACTH). This leads to bilateral adrenal cortical atrophy and the inability of the body to produce endogenous cortisol, especially during stress. **3. High-Yield Clinical Pearls for NEET-PG:** * **Muscle Effect:** Steroid-induced myopathy is typically **proximal and symmetrical** (e.g., difficulty climbing stairs). * **Bone Effect:** Steroids cause **Osteoporosis** by inhibiting osteoblast activity and decreasing calcium absorption (leading to secondary hyperparathyroidism). * **Fat Redistribution:** While they cause peripheral wasting, they cause central adiposity (Cushingoid features: Moon face, Buffalo hump, and Truncal obesity). * **Withdrawal:** Never stop long-term steroids abruptly; they must be **tapered** to allow the suppressed HPA axis to recover and prevent acute adrenal insufficiency (Addisonian crisis).

Question 352: A 57-year-old lady presents with type II diabetes mellitus with symptoms like polyuria, excessive thirst, fatigue, and blurred vision. Further investigation reveals insulin resistance. Which one of the following drugs is most appropriate for initiating treatment along with diet and exercise?

A. Pioglitazone
B. Metformin (Correct Answer)
C. Glimepiride
D. Repaglinide

Explanation: **Explanation:** **Why Metformin is the Correct Choice:** Metformin, a Biguanide, is the **first-line drug of choice** for Type 2 Diabetes Mellitus (T2DM) according to ADA and EASD guidelines [1]. Its primary mechanism of action is the activation of **AMP-activated protein kinase (AMPK)**, which leads to decreased hepatic gluconeogenesis and improved peripheral insulin sensitivity [2]. It is preferred for initiation because it is weight-neutral (or promotes slight weight loss), does not cause hypoglycemia, has a proven cardiovascular safety profile, and is cost-effective [1]. **Why Other Options are Incorrect:** * **Pioglitazone (Thiazolidinedione):** While it effectively reduces insulin resistance via PPAR-̳ activation [2], it is generally a second-line agent due to side effects like weight gain, edema, and risks of heart failure and osteoporosis [2]. * **Glimepiride (Sulfonylurea):** These are "insulin secretagogues." They carry a high risk of hypoglycemia and weight gain, making them less ideal than Metformin for initial monotherapy [1]. * **Repaglinide (Meglitinide):** Also a secretagogue with a short duration of action used primarily for postprandial hyperglycemia [3]. It requires multiple daily dosing and is not the standard first-line agent. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Metformin SE:** **M**etallic taste, **M**egaloblastic anemia (Vitamin B12 deficiency), and **M**ost serious side effect: Lactic Acidosis [2]. * **Contraindication:** Metformin should be avoided if eGFR < 30 mL/min due to the risk of lactic acidosis [2]. * **Efficacy:** Metformin typically reduces HbA1c by 1.0% to 1.5% [2]. * **Pleiotropic effect:** It is also used in Polycystic Ovary Syndrome (PCOS) to improve insulin sensitivity and ovulation.

Question 353: Which of the following group of antidiabetic drugs are contraindicated in patients with Multiple Endocrine Neoplasia (MEN) syndrome?

A. Biguanides
B. GLP-1 analogues (Correct Answer)
C. Alpha-glucosidase inhibitors
D. Meglitinides

Explanation: ### Explanation **Correct Option: B. GLP-1 analogues** The primary reason **GLP-1 analogues** (e.g., Liraglutide, Exenatide, Semaglutide) are contraindicated in patients with **Multiple Endocrine Neoplasia (MEN) type 2** is their association with **Medullary Thyroid Carcinoma (MTC)**. In rodent studies, GLP-1 receptor activation on thyroid C-cells (parafollicular cells) led to C-cell hyperplasia and the development of MTC. Since MEN 2A and 2B syndromes are characterized by a strong genetic predisposition to Medullary Thyroid Carcinoma (due to *RET* proto-oncogene mutations), these drugs are strictly contraindicated in patients with a personal or family history of MTC or MEN 2. **Analysis of Incorrect Options:** * **A. Biguanides (Metformin):** The first-line drug for Type 2 Diabetes. It has no association with thyroid tumors or MEN syndromes; in fact, it is being studied for potential anti-cancer properties. * **C. Alpha-glucosidase inhibitors (Acarbose, Voglibose):** These act locally in the GI tract to delay carbohydrate absorption. They have no systemic endocrine contraindications related to MEN. * **D. Meglitinides (Repaglinide, Nateglinide):** These are short-acting insulin secretagogues. Their side effect profile is mainly limited to hypoglycemia and weight gain, with no link to thyroid pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Black Box Warning:** All GLP-1 analogues carry a boxed warning regarding the risk of Thyroid C-cell tumors. * **DPP-4 Inhibitors:** Unlike GLP-1 analogues, DPP-4 inhibitors (Gliptins) have *not* shown a clear clinical link to MTC, though caution is often advised. * **Other Contraindications for GLP-1 analogues:** History of **Pancreatitis** (as they may increase the risk of acute pancreatitis) and severe renal impairment (specifically for Exenatide). * **MEN 2 Components:** Remember the "3 Ps" for MEN 1, but for **MEN 2A**, remember **MPH** (Medullary thyroid CA, Pheochromocytoma, Hyperparathyroidism).

Question 354: Which of the following characteristics makes metformin a preferred biguanide compared to phenformin?

A. It is more potent
B. It is less liable to cause lactic acidosis (Correct Answer)
C. It does not interfere with vitamin B12 absorption
D. It is not contraindicated in patients with kidney disease

Explanation: **Explanation:** **1. Why Option B is Correct:** The primary reason metformin replaced phenformin in clinical practice is its significantly lower risk of **lactic acidosis**. Phenformin was withdrawn globally in the 1970s because it has a high affinity for mitochondrial membranes, where it strongly inhibits the mitochondrial respiratory chain (Complex I). This leads to excessive anaerobic glycolysis and a massive buildup of lactate. Metformin, being less lipophilic, has a much weaker effect on mitochondrial respiration at therapeutic doses, making it a safer profile for glycemic control. **2. Why Other Options are Incorrect:** * **Option A:** Phenformin is actually **more potent** than metformin on a milligram-to-milligram basis, but its higher potency is associated with its increased toxicity. * **Option C:** Both metformin and phenformin can interfere with **Vitamin B12 absorption** in the terminal ileum. Long-term metformin use is a well-known cause of B12 deficiency, requiring periodic monitoring. * **Option D:** Metformin is primarily excreted unchanged by the kidneys. Therefore, it is **contraindicated** in patients with significant renal impairment (typically eGFR <30 mL/min) due to the increased risk of accumulation and subsequent lactic acidosis. **3. Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Metformin activates **AMP-activated protein kinase (AMPK)**, leading to decreased hepatic gluconeogenesis and improved peripheral insulin sensitivity. * **Weight Neutrality:** Unlike sulfonylureas or insulin, metformin does not cause weight gain; it is often weight-neutral or promotes modest weight loss. * **First-line Status:** It is the drug of choice for Type 2 Diabetes Mellitus, especially in obese patients. * **Side Effects:** The most common side effects are GI-related (diarrhea, abdominal cramps). The most serious (though rare) is lactic acidosis.

Question 355: Which drug's action requires the presence of insulin to produce its therapeutic effect?

A. Glibenclamide
B. Nateglinide
C. Pioglitazone (Correct Answer)
D. Empagliflozin

Explanation: **Explanation:** The correct answer is **Pioglitazone**. **1. Why Pioglitazone is correct:** Pioglitazone belongs to the **Thiazolidinedione (TZD)** class. Its primary mechanism of action is as a selective agonist for the nuclear receptor **PPAR-γ** (Peroxisome Proliferator-Activated Receptor gamma). Activation of this receptor increases the transcription of genes involved in glucose and lipid metabolism, effectively acting as an **insulin sensitizer**. Because Pioglitazone works by enhancing the body's response to insulin (reducing insulin resistance in muscle, fat, and liver), it is physiologically dependent on the presence of either endogenous or exogenous insulin to exert its glucose-lowering effect. **2. Analysis of Incorrect Options:** * **A. Glibenclamide (Sulfonylurea):** These are insulin secretagogues. They work by closing ATP-sensitive K+ channels in pancreatic beta cells, causing depolarization and insulin release. They require functional beta cells, but not the presence of insulin itself, to act. * **B. Nateglinide (Meglitinide):** Similar to sulfonylureas, these are short-acting secretagogues that stimulate the release of insulin from the pancreas. * **C. Empagliflozin (SGLT-2 Inhibitor):** This drug acts on the proximal convoluted tubule of the kidney to inhibit glucose reabsorption. Its mechanism is entirely **insulin-independent**, making it effective even in states of absolute insulin deficiency. **3. NEET-PG High-Yield Pearls:** * **TZDs and Weight:** Unlike many other antidiabetics, TZDs can cause weight gain (due to fluid retention and adipocyte differentiation). * **Contraindication:** Avoid TZDs in patients with NYHA Class III/IV Heart Failure due to the risk of fluid overload. * **Metformin vs. Pioglitazone:** Both are sensitizers, but Metformin primarily acts on the liver (AMPK activation), while TZDs primarily act on peripheral tissues (PPAR-γ).

Question 356: A patient diagnosed with a brain tumor is to be treated with steroids to decrease cerebral edema. Which type of steroid is preferred and why?

A. The preferred steroids cause less sodium and water retention. (Correct Answer)
B. The preferred steroids are more potent.
C. The preferred steroids can be administered intravenously.
D. The preferred steroids inhibit brain tumors directly.

Explanation: **Explanation:** In the management of vasogenic cerebral edema associated with brain tumors, **Dexamethasone** is the drug of choice. **1. Why Option A is correct:** The primary goal in treating cerebral edema is to reduce intracranial pressure (ICP). Steroids like Dexamethasone are preferred because they possess **minimal to zero mineralocorticoid activity**. Unlike hydrocortisone, which causes significant sodium and water retention, Dexamethasone does not promote fluid accumulation. In a patient already suffering from brain swelling, any additional systemic fluid retention would worsen the edema and further elevate ICP. **2. Why other options are incorrect:** * **Option B:** While Dexamethasone is indeed highly potent (about 25–30 times more than cortisol), potency refers to the dose required to achieve an effect, not the therapeutic rationale. The *lack of mineralocorticoid effect* is the specific clinical reason for its selection in edema. * **Option C:** Many steroids (Hydrocortisone, Methylprednisolone) can be administered intravenously. This is not a unique property of the preferred steroid for brain tumors. * **Option D:** Steroids do not directly inhibit the growth of most primary brain tumors (except for certain lymphomas). Their role is purely symptomatic—to stabilize the blood-brain barrier and reduce capillary permeability. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Dexamethasone (Long-acting glucocorticoid). * **Mechanism:** Reduces peritumoral edema by decreasing capillary permeability (stabilizing the blood-brain barrier). * **Half-life:** Dexamethasone has a long biological half-life (36–72 hours), allowing for less frequent dosing. * **Side Effect Profile:** Because it lacks mineralocorticoid activity, it is also preferred in conditions like high-altitude cerebral edema (HACE).

Question 357: Which of the following drugs does not increase insulin secretion?

A. Rosiglitazone (Correct Answer)
B. Repaglinide
C. Exenatide
D. Sitagliptin

Explanation: ### Explanation The correct answer is **Rosiglitazone**. #### 1. Why Rosiglitazone is Correct Rosiglitazone belongs to the **Thiazolidinedione (TZD)** class. Its primary mechanism of action is as a selective agonist for the nuclear receptor **PPAR-γ** (Peroxisome Proliferator-Activated Receptor-gamma). Instead of stimulating insulin secretion from the pancreas, it acts as an **insulin sensitizer**. It increases glucose uptake in peripheral tissues (skeletal muscle and adipose tissue) and decreases hepatic glucose production. Since it does not act on beta cells to release insulin, it is not associated with hypoglycemia when used as monotherapy. #### 2. Why the Other Options are Incorrect * **Repaglinide:** A **Meglitinide** analogue. It acts as an insulin secretagogue by closing ATP-sensitive K⁺ channels in pancreatic beta cells, similar to sulfonylureas but with a faster onset and shorter duration. * **Exenatide:** A **GLP-1 Receptor Agonist** (Incretin mimetic). It stimulates glucose-dependent insulin secretion, suppresses glucagon release, and slows gastric emptying. * **Sitagliptin:** A **DPP-4 Inhibitor**. It prevents the breakdown of endogenous GLP-1 and GIP, thereby increasing insulin secretion in a glucose-dependent manner. #### 3. High-Yield Clinical Pearls for NEET-PG * **Weight Gain:** Both TZDs (Rosiglitazone) and Secretagogues (Repaglinide) cause weight gain, whereas GLP-1 agonists (Exenatide) cause weight loss. * **Side Effects of TZDs:** Fluid retention (edema), congestive heart failure exacerbation, and increased risk of bone fractures. * **Euglycemics:** Drugs like Metformin and TZDs are termed "euglycemics" because they improve glucose utilization without the risk of inducing hypoglycemia. * **Glucose-Dependency:** GLP-1 agonists and DPP-4 inhibitors only increase insulin secretion when blood glucose is high, significantly reducing the risk of hypoglycemia compared to Meglitinides.

Question 358: In terms of birth defect potential, which of the following drugs is the safest?

A. Alcohol
B. Isotretinoin (Accutane)
C. Tetracyclines
D. Progesterone (Correct Answer)

Explanation: **Explanation:** The correct answer is **Progesterone**. In pharmacological terms, drugs are classified based on their teratogenic potential. Progesterone is a naturally occurring hormone essential for maintaining pregnancy and is generally considered safe when used appropriately (e.g., for luteal phase support or prevention of preterm labor). Unlike the other options, it does not have a proven association with structural birth defects in humans. **Why the other options are incorrect:** * **Alcohol:** A potent teratogen and the leading cause of preventable intellectual disability. It causes **Fetal Alcohol Syndrome (FAS)**, characterized by craniofacial abnormalities (short palpebral fissures, thin upper lip), growth retardation, and CNS dysfunction. * **Isotretinoin:** A Vitamin A derivative used for acne, it is highly teratogenic (Category X). It causes **Retinoic Acid Embryopathy**, involving severe craniofacial, cardiac, and CNS defects (e.g., microtia, hydrocephalus). * **Tetracyclines:** These are contraindicated in pregnancy because they cross the placenta and chelate calcium. This leads to **permanent discoloration of deciduous teeth** and inhibition of bone growth in the fetus. **High-Yield Clinical Pearls for NEET-PG:** * **Thalidomide:** Causes Phocomelia (seal-like limbs). * **Valproate:** Highest risk of Neural Tube Defects (NTDs). * **Warfarin:** Causes Fetal Warfarin Syndrome (stippled epiphyses and nasal hypoplasia). * **Phenytoin:** Causes Fetal Hydantoin Syndrome (cleft lip/palate and digital hypoplasia). * **ACE Inhibitors:** Cause renal dysgenesis and oligohydramnios in the 2nd/3rd trimesters.

Question 359: By binding RANKL with high affinity, which of the following drugs reduces bone resorption?

A. Alemtuzumab
B. Palivizumab
C. Daclizumab
D. Denosumab (Correct Answer)

Explanation: **Explanation:** **Denosumab** is the correct answer because it is a human monoclonal antibody that specifically targets and binds to **RANKL** (Receptor Activator of Nuclear Factor kappa-B Ligand). Under normal physiological conditions, RANKL is secreted by osteoblasts and binds to RANK receptors on osteoclast precursors, leading to their maturation and activation. By inhibiting RANKL, Denosumab prevents osteoclast formation, thereby decreasing bone resorption and increasing bone mineral density. **Analysis of Incorrect Options:** * **Alemtuzumab (A):** A monoclonal antibody against **CD52**, primarily used in B-cell chronic lymphocytic leukemia (CLL) and Multiple Sclerosis. * **Palivizumab (B):** Targets the **F protein** of Respiratory Syncytial Virus (RSV); used for prophylaxis in high-risk infants. * **Daclizumab (C):** An antibody against the **IL-2 receptor (CD25)**; formerly used in Multiple Sclerosis (now largely withdrawn due to toxicity). **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Denosumab is used for Postmenopausal Osteoporosis and Giant Cell Tumor of Bone. * **Administration:** It is administered **subcutaneously** every 6 months. * **Adverse Effects:** It may cause hypocalcemia (ensure Vitamin D/Calcium supplementation) and, rarely, Osteonecrosis of the Jaw (ONJ). * **Comparison:** Unlike Bisphosphonates, Denosumab can be used in patients with **renal impairment** as it is not cleared by the kidneys. * **OPG Connection:** Denosumab mimics the natural action of **Osteoprotegerin (OPG)**, the body's endogenous RANKL decoy receptor.

Question 360: Parathormone is useful in which of the following conditions?

A. Hyperparathyroidism (Correct Answer)
B. Paget's disease
C. Osteoporosis
D. Osteomalacia

Explanation: **Explanation:** **Correct Option: A (Hyperparathyroidism)** While it may seem counterintuitive to use Parathormone (PTH) in hyperparathyroidism, the question refers to the **diagnostic** utility of PTH (specifically the **Ellsworth-Howard test**). In **Pseudohypoparathyroidism**, there is end-organ resistance to PTH. To differentiate it from true hypoparathyroidism, exogenous PTH is administered. In a normal individual or a patient with hypoparathyroidism, PTH administration causes a significant rise in urinary cAMP and phosphate excretion. In Pseudohypoparathyroidism, this response is absent. Thus, PTH is "useful" as a diagnostic tool in the workup of these disorders. **Incorrect Options:** * **B. Paget’s Disease:** This condition involves excessive bone remodeling. Treatment focuses on inhibiting osteoclasts using **Bisphosphonates** or **Calcitonin**. PTH would worsen the condition by further stimulating bone turnover. * **C. Osteoporosis:** While PTH *analogs* (like **Teriparatide**) are used to treat osteoporosis via intermittent pulsatile dosing, native Parathormone itself is generally not the therapeutic agent of choice. However, in the context of this specific question (often a repeat from older medical exams), "Hyperparathyroidism" is the classic answer regarding its diagnostic utility. * **D. Osteomalacia:** This is caused by Vitamin D deficiency or phosphate wasting. Treatment involves Vitamin D and Calcium supplementation, not PTH. **High-Yield Clinical Pearls for NEET-PG:** * **Teriparatide:** A recombinant PTH (1-34) used in osteoporosis. It has an **anabolic effect** on bone when given in intermittent low doses. * **Continuous vs. Intermittent PTH:** Continuous high levels (Hyperparathyroidism) cause bone resorption (osteoclast activity), while intermittent low doses (Teriparatide) stimulate bone formation (osteoblast activity). * **Cinacalcet:** A calcimimetic used to treat secondary hyperparathyroidism by increasing the sensitivity of calcium-sensing receptors on the parathyroid gland.

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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