Endocrine Pharmacology Practice Questions

Q: Which one of the following statements about the mechanism of action of Metformin is true?

Enhances glucose uptake by skeletal muscle. **Explanation:** Metformin is a **Biguanide** and is currently the first-line oral hypoglycemic agent for Type 2 Diabetes Mellitus. Unlike sulfonylureas, it does not act by increasing insulin secretion; instead, it is an **insulin sensitizer**. **Why Option C is Correct:** The primary mechanism of Metformin involves the activation of **AMP-activated protein kinase (AMPK)**. In skeletal muscle, this activation triggers the translocation of **GLUT-4 transporters** to the cell membrane, significantly enhancing peripheral glucose uptake and utilization. This reduces insulin resistance without causing weight gain. **Why Other Options are Incorrect:** * **Options A & B:** Metformin **inhibits** hepatic gluconeogenesis and glycogenolysis. By suppressing these processes, it reduces the excessive hepatic glucose output typically seen in diabetic patients. * **Option D:** This describes the mechanism of **Sulfonylureas** (e.g., Glipizide) and **Meglitinides**. Metformin is "euglycemic"; it does not stimulate insulin release from pancreatic beta cells, which is why it carries a very low risk of hypoglycemia when used as monotherapy. **High-Yield NEET-PG Pearls:** 1. **Drug of Choice:** First-line for T2DM, especially in obese patients (weight neutral/loss). 2. **PCOS:** Used to improve ovulation and menstrual regularity by reducing insulin resistance. 3. **Side Effects:** Most common are GI upset (diarrhea, abdominal pain). The most serious, though rare, is **Lactic Acidosis** (contraindicated in renal failure, Cr >1.5 mg/dL). 4. **Vitamin Deficiency:** Long-term use can lead to **Vitamin B12 deficiency** due to malabsorption in the terminal ileum.

Q: Glucocorticoids cause all of the following, except?

Reduced appetite. **Explanation:** Glucocorticoids (like Cortisol or Prednisolone) are catabolic hormones that significantly impact metabolism and electrolyte balance. **Why "Reduced appetite" is the correct answer:** Glucocorticoids actually **increase appetite** (polyphagia) rather than reducing it. This occurs through the stimulation of neuropeptide Y and the inhibition of POMC neurons in the hypothalamus. Long-term use leads to weight gain and the characteristic "Cushingoid" fat redistribution (moon face, buffalo hump, and truncal obesity). **Analysis of Incorrect Options:** * **Muscle wasting:** Glucocorticoids promote protein breakdown (catabolism) in skeletal muscle to provide amino acids for gluconeogenesis. This leads to proximal muscle weakness and thinning of the limbs. * **Osteoporosis:** Steroids decrease bone formation by inhibiting osteoblasts and increase bone resorption by osteoclasts. They also decrease intestinal calcium absorption, making osteoporosis a major side effect of chronic therapy. * **Diabetes mellitus:** Glucocorticoids are "diabetogenic." They increase blood glucose levels by stimulating hepatic gluconeogenesis and decreasing peripheral glucose uptake (anti-insulin effect). This can unmask latent diabetes or worsen glycemic control in existing diabetics. **High-Yield Clinical Pearls for NEET-PG:** * **Psychiatric effects:** Glucocorticoids can cause "steroid psychosis," ranging from euphoria and insomnia to depression and mania. * **Hematological effects:** They cause **lymphocytopenia**, eosinopenia, and monocytopenia, but lead to **neutrophilia** (due to demargination from blood vessel walls) and polycythemia. * **Wound healing:** They inhibit fibroblast proliferation and collagen synthesis, leading to delayed wound healing and purple striae.

Q: What is an adverse effect of tocolytic agonists during pregnancy?

All of the above. **Explanation:** Tocolytic agonists, specifically **Beta-2 ($\beta_2$) selective agonists** like **Ritodrine** and **Terbutaline**, are used to delay preterm labor by relaxing uterine smooth muscle. However, their selectivity is not absolute, leading to significant systemic side effects due to the stimulation of $\beta_1$ and $\beta_2$ receptors elsewhere in the body. 1. **Pulmonary Edema:** This is the most serious respiratory complication. It occurs due to a combination of $\beta$-agonist-induced fluid retention, increased capillary permeability, and the high cardiac output state of pregnancy. The risk increases significantly when these drugs are administered with large volumes of intravenous fluids or corticosteroids. 2. **Arrhythmia:** While these drugs are $\beta_2$ selective, at higher doses they cross-react with **$\beta_1$ receptors** in the heart. This causes positive chronotropic and inotropic effects, leading to maternal tachycardia, palpitations, and potentially cardiac arrhythmias. 3. **Hypokalemia:** $\beta_2$ stimulation activates the **Na+/K+ ATPase pump**, causing an intracellular shift of potassium. This results in a transient decrease in serum potassium levels. **Clinical Pearls for NEET-PG:** * **Metabolic Effects:** $\beta_2$ agonists also cause **hyperglycemia** (due to glycogenolysis) and hyperinsulinemia. * **Drug of Choice:** Due to the high side-effect profile of $\beta$-agonists, **Nifedipine** (Calcium Channel Blocker) or **Atosiban** (Oxytocin antagonist) are now preferred as first-line tocolytics. * **Contraindication:** $\beta$-agonists should be avoided in pregnant women with pre-existing heart disease or poorly controlled diabetes.

Q: Which of the following is a side effect of Octreotide?

Cholesterol gallstones. **Explanation:** **Octreotide** is a synthetic long-acting analogue of **Somatostatin**. It acts by binding to somatostatin receptors (SSTR-2 and SSTR-5), leading to the inhibition of various hormones, including Growth Hormone (GH), Glucagon, Insulin, and Gastrin. **Why Cholesterol Gallstones occur (Correct Answer):** Octreotide significantly inhibits the secretion of **Cholecystokinin (CCK)** and reduces gallbladder contractility. This leads to biliary stasis and increased concentration of bile. Long-term use (usually >6 months) results in the formation of biliary sludge and **cholesterol gallstones** in up to 50% of patients. **Analysis of Incorrect Options:** * **A. Arrhythmias:** While bradycardia can occur, it is not the most characteristic or frequently tested side effect compared to biliary issues. * **C. Hyperglycemia:** Octreotide inhibits both insulin and glucagon. While it can cause transient hyperglycemia, it more commonly causes **hypoglycemia** or has a neutral effect on blood glucose in acromegalic patients. * **D. Diarrhea:** Octreotide actually causes **steatorrhea** (fatty stools) due to the inhibition of pancreatic enzymes, but it is clinically used to *treat* secretory diarrhea (e.g., in VIPoma or Carcinoid syndrome). **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Octreotide is the DOC for **Esophageal Variceal Bleeding** (causes splanchnic vasoconstriction) and **Acromegaly**. * **Diagnostic Use:** Radiolabeled octreotide (OctreoScan) is used for localizing neuroendocrine tumors. * **Key Side Effects:** Steatorrhea, nausea, and abdominal cramps (usually transient), and cholelithiasis (long-term).

Question 1

Which one of the following statements about the mechanism of action of Metformin is true?

Accepted Answer

Enhances glucose uptake by skeletal muscle

Answer

Stimulates glycogenolysis

Answer

Stimulates hepatic gluconeogenesis

Answer

Releases insulin from beta cells of the pancreas

Question 2

A patient with chronic kidney disease stage 4 is receiving insulin therapy. What adjustment in insulin dosage is required?

Accepted Answer

Decrease dose of insulin

Answer

Increase dose of insulin

Answer

Variable dose

Answer

No alteration in dose

Question 3

Glucocorticoids cause all of the following, except?

Accepted Answer

Reduced appetite

Answer

Muscle wasting

Answer

Osteoporosis

Answer

Diabetes mellitus

Question 4

Which of the following statements about Afrezza is incorrect?

Accepted Answer

It has a longer duration of action than injected insulin analogues.

Answer

It is an inhaled form of insulin.

Answer

It should be avoided in smokers.

Answer

Adverse effects include cough and throat irritation.

Question 5

What is an adverse effect of tocolytic agonists during pregnancy?

Accepted Answer

All of the above

Answer

Pulmonary edema

Answer

Arrhythmia

Answer

Hypokalemia

Question 6

What is the difference between carbimazole and propylthiouracil?

Accepted Answer

Carbimazole does not inhibit the peripheral conversion of T4 to T3.

Answer

Carbimazole is less potent.

Answer

Carbimazole is shorter acting.

Answer

Carbimazole does not produce an active metabolite.

Question 7

Niacin is dangerous in diabetes mellitus because:

Accepted Answer

It causes insulin resistance

Answer

It causes sudden hypoglycemia

Answer

It decreases glucagon secretion

Answer

It decreases the effect of other oral hypoglycemic agents

Question 8

Adrenal suppression is caused by all of the following drugs EXCEPT?

Accepted Answer

Erythromycin

Answer

Ketoconazole

Answer

Rifampicin

Answer

Phenytoin

Question 9

Which of the following is a side effect of Octreotide?

Accepted Answer

Cholesterol gallstones

Answer

Arrhythmias

Answer

Hyperglycemia

Answer

Diarrhea

Question 10

Which of the following statements about Repaglinide is true?

Accepted Answer

It should be avoided in patients with liver diseases.

Answer

It belongs to the sulfonylurea class of drugs.

Answer

It is not well absorbed on oral administration.

Answer

It is used to control postprandial hyperglycemia.

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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