Endocrine Pharmacology Practice Questions

Q: All of the following are used in the treatment of hypercalcemia, except:

Vitamin D in high dose. **Explanation:** The management of hypercalcemia focuses on reducing serum calcium levels by inhibiting bone resorption, increasing renal excretion, or decreasing intestinal absorption. **Why Vitamin D is the Correct Answer:** Vitamin D (in high doses) is **contraindicated** in hypercalcemia because its primary physiological role is to **increase** serum calcium levels. It achieves this by enhancing intestinal calcium absorption and stimulating osteoclast activity (bone resorption). Administering high-dose Vitamin D would exacerbate hypercalcemia, potentially leading to a hypercalcemic crisis. In fact, Vitamin D toxicity is a known cause of hypercalcemia. **Analysis of Other Options:** * **Phosphate (Option A):** Intravenous or oral phosphate can be used to treat hypercalcemia. It works by promoting the deposition of calcium into the bone and soft tissues (forming calcium phosphate), thereby lowering serum levels. However, it is used cautiously due to the risk of ectopic calcification. * **Mithramycin (Plicamycin) (Option B):** This is a cytotoxic antibiotic that, in lower doses, acts as a potent inhibitor of osteoclastic bone resorption. It was traditionally used for hypercalcemia of malignancy, though it has largely been replaced by bisphosphonates due to toxicity. **NEET-PG High-Yield Pearls:** * **First-line treatment:** Vigorous rehydration with **Normal Saline (0.9% NaCl)** is the most crucial initial step. * **Loop Diuretics:** Furosemide is used *after* rehydration to promote calciuresis (forced diuresis). * **Bisphosphonates (e.g., Zoledronate, Pamidronate):** These are the drugs of choice for hypercalcemia of malignancy. * **Calcitonin:** Used for rapid, short-term reduction of calcium (works within hours but exhibits tachyphylaxis). * **Glucocorticoids:** Effective specifically for hypercalcemia caused by sarcoidosis, lymphomas, or Vitamin D intoxication.

Q: Which is not a side effect of Growth Hormone (GH) administration?

Hypoglycemia. **Explanation:** Growth Hormone (GH) administration is associated with several metabolic and structural side effects, but it does **not** cause hypoglycemia. **1. Why Hypoglycemia is the correct answer:** Growth Hormone is a **diabetogenic hormone**. It antagonizes the action of insulin, decreases peripheral glucose utilization, and increases hepatic gluconeogenesis. Therefore, GH administration leads to **hyperglycemia** and insulin resistance, not hypoglycemia. In patients with pre-existing diabetes, GH therapy often necessitates an increase in insulin dosage. **2. Analysis of incorrect options:** * **Gynecomastia:** GH has structural similarities to Prolactin and can stimulate mammary tissue, leading to gynecomastia in some males. * **Slipped Capital Femoral Epiphysis (SCFE):** Rapid longitudinal bone growth induced by GH can place mechanical stress on the growth plates, particularly in the hip, making SCFE a known orthopedic complication in children. * **Pseudotumor Cerebri (Idiopathic Intracranial Hypertension):** GH can cause fluid retention and altered CSF dynamics, leading to increased intracranial pressure, headache, and papilledema. **Clinical Pearls for NEET-PG:** * **Metabolic effects:** GH increases lipolysis (increasing free fatty acids) and promotes a positive nitrogen balance (anabolic). * **Monitoring:** Children on GH therapy should be monitored for limping (SCFE) and severe headaches (Pseudotumor cerebri). * **Laron Syndrome:** A condition of GH resistance due to receptor mutations; treated with **Mecasermin** (recombinant IGF-1). * **Somatostatin Analogs:** Octreotide and Lanreotide are used to treat Acromegaly by inhibiting GH secretion.

Q: Gestrinone has the following actions except?

Anti-androgenic. **Explanation:** Gestrinone is a synthetic steroid derivative of 19-nortestosterone primarily used in the treatment of endometriosis. To understand its mechanism, it is essential to recognize its **mixed agonist-antagonist profile** on various steroid receptors. **Why "Anti-androgenic" is the correct answer:** Gestrinone possesses significant **androgenic** activity rather than anti-androgenic activity. It binds to androgen receptors and exerts agonist effects, which contributes to its side effect profile (e.g., weight gain, acne, and hirsutism). Therefore, stating it is "anti-androgenic" is pharmacologically incorrect. **Analysis of other options:** * **Androgenic (A):** As a 19-nortestosterone derivative, it has inherent weak androgenic properties. * **Anti-oestrogenic (B):** It acts centrally to suppress the mid-cycle surge of LH and FSH, leading to decreased ovarian estrogen production. It also has direct antagonistic effects at the endometrial level. * **Anti-progestogenic (D):** Gestrinone acts as a selective progesterone receptor modulator (SPRM) with predominant **antagonist** activity on the endometrium, leading to atrophy of ectopic endometrial tissue. **Clinical Pearls for NEET-PG:** * **Primary Indication:** Second-line treatment for **Endometriosis** (similar efficacy to Danazol but with a longer half-life, allowing twice-weekly dosing). * **Mechanism Summary:** It creates a "high-androgen, low-estrogen" environment that induces atrophy of the endometrium. * **Contraindications:** Pregnancy (due to virilization of a female fetus) and severe hepatic/renal impairment. * **Key Side Effects:** Acne, oily skin, hirsutism, and voice changes (due to its androgenic nature).

Q: All of the following are effects of estrogen, EXCEPT:

Increased protein C and S levels. **Explanation:** The correct answer is **D (Increased protein C and S levels)** because estrogen actually **decreases** the levels of Protein C and Protein S (natural anticoagulants) and increases the levels of clotting factors (II, VII, IX, and X). This shift creates a **pro-thrombotic state**, increasing the risk of deep vein thrombosis (DVT) and pulmonary embolism. **Analysis of Options:** * **A. Beneficial effect on cognition:** Estrogen has neuroprotective properties. It enhances synaptic plasticity and cerebral blood flow, which is why postmenopausal estrogen deficiency is often linked to "brain fog" or cognitive decline. * **B & C. Effects on Bone (Osteoclasts/Osteoblastic activity):** Estrogen is vital for bone health. It **reduces osteoclastic activity** (by inducing apoptosis of osteoclasts and inhibiting RANKL) and **increases osteoblastic activity** (by stimulating TGF-β). This dual action prevents bone resorption and maintains bone mineral density. **NEET-PG High-Yield Pearls:** * **Lipid Profile:** Estrogen increases HDL ("good" cholesterol) and decreases LDL, but it also **increases Triglycerides**. * **Biliary System:** It increases cholesterol secretion in bile, leading to a higher risk of **gallstones** (cholelithiasis). * **Cancer Risk:** Unopposed estrogen increases the risk of **endometrial carcinoma**; hence, it is always combined with progestins in women with an intact uterus. * **Metabolism:** Estrogen increases the synthesis of transport proteins in the liver, such as Sex Hormone Binding Globulin (SHBG) and Thyroid Binding Globulin (TBG).

Q: Which of the following is NOT a true statement regarding oral hypoglycemic agents?

They are effective only after total pancreatectomy.. ### Explanation **1. Why Option A is the Correct Answer (The False Statement):** Oral hypoglycemic agents (OHAs), specifically secretagogues like Sulfonylureas and Meglitinides, require **functional pancreatic beta-cells** to exert their effect [1]. A total pancreatectomy results in the absolute loss of all beta-cells, leading to surgical diabetes (similar to Type 1 DM). In the absence of endogenous insulin production, OHAs are completely ineffective. Patients post-pancreatectomy require exogenous insulin therapy for survival. **2. Analysis of Incorrect Options (True Statements):** * **Option B:** Metformin (a Biguanide) inhibits mitochondrial respiration, which can lead to an accumulation of lactate. While rare, **lactic acidosis** is a serious potential side effect, especially in patients with renal impairment or hepatic failure. * **Option C:** Sulfonylureas (e.g., Glipizide) and Meglitinides (e.g., Repaglinide) act by closing ATP-sensitive potassium channels on beta-cells, causing depolarization and subsequent **insulin release** [1], [2]. * **Option D:** **Metformin** is the first-line drug for obese patients with Type 2 Diabetes (maturity-onset) because it promotes modest weight loss and improves insulin sensitivity without causing hypoglycemia [3]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Metformin is the first-line agent for Type 2 DM unless contraindicated (CrCl <30 mL/min) [3]. * **Weight Neutral/Loss:** Metformin and GLP-1 agonists (e.g., Liraglutide) help with weight loss; SGLT-2 inhibitors (e.g., Dapagliflozin) also promote weight loss via glucosuria [3]. * **Weight Gain:** Sulfonylureas and Thiazolidinediones (Pioglitazone) are associated with weight gain. * **Disulfiram-like reaction:** Classically associated with first-generation sulfonylureas like **Chlorpropamide**.

Q: Lactic acidosis is a potential side effect of which of the following medications?

Metformin. **Explanation:** **Correct Answer: B. Metformin** Metformin, a Biguanide, is the first-line agent for Type 2 Diabetes Mellitus [1]. Its primary mechanism involves the activation of **AMP-activated protein kinase (AMPK)**, which leads to decreased hepatic gluconeogenesis. A critical metabolic consequence of metformin is the inhibition of **pyruvate carboxylase** and the mitochondrial respiratory chain (Complex I). This inhibition prevents the conversion of lactate back into glucose (gluconeogenesis), leading to an accumulation of lactate in the blood. While rare, **Metformin-Associated Lactic Acidosis (MALA)** is a life-threatening complication, especially in patients with renal impairment (eGFR <30 ml/min), as the drug is excreted unchanged by the kidneys [1]. **Incorrect Options:** * **A. Chlorothiazide:** A thiazide diuretic primarily associated with metabolic alkalosis (due to hypokalemia and H+ loss) and hyperglycemia, but not lactic acidosis. * **C. Cyclosporine:** An immunosuppressant (calcineurin inhibitor) known for nephrotoxicity, hypertension, and hyperkalemia, but it does not typically cause lactic acidosis. * **D. Pentamidine:** Used for *Pneumocystis jirovecii*, it is notorious for causing pancreatic toxicity (hypoglycemia followed by hyperglycemia) and nephrotoxicity. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Metformin side effects:** **L**actic acidosis, **A**norexia, **M**etallic taste, **B**12 deficiency (megaloblastic anemia). * **Contraindication:** Metformin must be temporarily discontinued before **IV contrast** studies to prevent acute kidney injury, which could precipitate lactic acidosis. * **Weight Neutrality:** Unlike sulfonylureas or insulin, Metformin does not cause weight gain and is often associated with modest weight loss [2].

Q: Bisphosphonates act by which of the following mechanisms?

Decreasing osteoclast-mediated resorption of bone. **Explanation:** **Mechanism of Action (Why C is correct):** Bisphosphonates are synthetic analogs of pyrophosphate that have a high affinity for hydroxyapatite crystals in the bone. They primarily act by **inhibiting osteoclast-mediated bone resorption**. * **Simple Bisphosphonates (e.g., Etidronate):** Are metabolized into non-functional ATP analogs that induce osteoclast apoptosis. * **Nitrogen-containing Bisphosphonates (e.g., Alendronate, Zoledronate):** Inhibit the enzyme **farnesyl pyrophosphate (FPP) synthase** in the mevalonate pathway. This prevents the prenylation of GTP-binding proteins (like Rho and Ras) necessary for osteoclast survival and their "ruffled border" formation, leading to reduced bone resorption. **Analysis of Incorrect Options:** * **Options A & B:** Bisphosphonates do not stimulate osteoblasts or increase osteoid formation/mineralization. In fact, high doses of older bisphosphonates (Etidronate) can actually *impair* mineralization. Drugs that increase bone formation (anabolic agents) include Teriparatide. * **Option D:** Bisphosphonates do not directly affect the parathyroid gland. However, by decreasing bone resorption, they may cause a transient compensatory *increase* in PTH due to a slight drop in serum calcium. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** Bisphosphonates are the first-line treatment for **Postmenopausal Osteoporosis** and **Paget’s Disease**. * **Administration:** Oral bisphosphonates (Alendronate) 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**. * **Adverse Effects:** Osteonecrosis of the Jaw (ONJ) and atypical subtrochanteric fractures (with long-term use). * **Potency:** Zoledronate is the most potent bisphosphonate and is administered intravenously once yearly.

Q: Which drug decreases the efficacy of testosterone?

Ketoconazole. **Explanation** The correct answer is **Ketoconazole**. **Mechanism of Action (Why it is correct):** Ketoconazole is a broad-spectrum imidazole antifungal that acts as a potent inhibitor of steroid synthesis. It inhibits the enzyme **17,20-lyase** (and to a lesser extent, CYP11A1/side-chain cleavage enzyme), which are essential steps in the conversion of cholesterol to androgens. By blocking these enzymes in both the testes and the adrenal glands, it significantly reduces testosterone production. Additionally, at high doses, it can displace testosterone from sex hormone-binding globulin (SHBG), further altering its efficacy. **Analysis of Incorrect Options:** * **Isoniazid (A):** While Isoniazid is a CYP450 inhibitor, it does not have a clinically significant effect on the steroidogenic pathways or the efficacy of testosterone. Its primary side effects are peripheral neuropathy and hepatotoxicity. * **Rifampicin (C):** Rifampicin is a potent **enzyme inducer**. While it can increase the metabolism of many steroid hormones (like oral contraceptives), it does not directly decrease the efficacy of testosterone in the same targeted, inhibitory manner as Ketoconazole. In fact, it often leads to a compensatory rise in LH and testosterone levels. **Clinical Pearls for NEET-PG:** * **Anti-androgenic side effects:** Due to testosterone inhibition, Ketoconazole can cause **gynecomastia**, decreased libido, and erectile dysfunction in men. * **Clinical Use:** Because of its ability to inhibit steroidogenesis, high-dose Ketoconazole is sometimes used off-label to treat **Cushing’s syndrome** and advanced **prostate cancer**. * **Other Drugs causing Gynecomastia (Mnemonic: DISCO):** **D**igoxin, **I**soniazid (rarely), **S**pironolactone, **C**imetidine, **O**estrogens/Ketoconazole.

Question 1

In the treatment of hypothyroidism, why is thyroxine generally preferred over liothyronine?

Accepted Answer

Thyroxine possesses a longer half-life.

Answer

Thyroxine has a faster onset of action.

Answer

Thyroxine exhibits higher affinity for thyroid hormone receptors.

Answer

Thyroxine can be synthesized more readily using recombinant DNA technology.

Question 2

All of the following are used in the treatment of hypercalcemia, except:

Accepted Answer

Vitamin D in high dose

Answer

Phosphate

Answer

Mithramycin

Answer

Any of the above

Question 3

Which is not a side effect of Growth Hormone (GH) administration?

Accepted Answer

Hypoglycemia

Answer

Gynecomastia

Answer

Slipped capital femoral epiphysis

Answer

Pseudotumor cerebri

Question 4

Gestrinone has the following actions except?

Accepted Answer

Anti-androgenic

Answer

Androgenic

Answer

Anti-oestrogenic

Answer

Anti-progestogenic

Question 5

All of the following antidiabetic drugs act by enhancing insulin sensitivity except?

Accepted Answer

Rosiglitazone

Answer

Exenatide

Answer

Sitagliptin

Answer

Repaglinide

Question 6

All of the following are effects of estrogen, EXCEPT:

Accepted Answer

Increased protein C and S levels

Answer

Beneficial effect on cognition

Answer

Reduced osteoclastic activity

Answer

Increased osteoblastic activity

Question 7

Which of the following is NOT a true statement regarding oral hypoglycemic agents?

Accepted Answer

They are effective only after total pancreatectomy.

Answer

Metformin is associated with a risk of lactic acidosis.

Answer

Some agents stimulate the release of insulin from pancreatic beta-cells.

Answer

They are useful in obese patients with maturity-onset diabetes.

Question 8

Lactic acidosis is a potential side effect of which of the following medications?

Accepted Answer

Metformin

Answer

Chlorothiazide

Answer

Cyclosporine

Answer

Pentamidine

Question 9

Bisphosphonates act by which of the following mechanisms?

Accepted Answer

Decreasing osteoclast-mediated resorption of bone

Answer

Increasing osteoid formation

Answer

Increasing the mineralization of osteoid

Answer

Decreasing parathyroid hormone secretion

Question 10

Which drug decreases the efficacy of testosterone?

Accepted Answer

Ketoconazole

Answer

Isoniazid

Answer

Rifampicin

Answer

None

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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