Screening for antidyslipidemic and diuretic agents MCQs With Answer

Introduction: Screening for antidyslipidemic and diuretic agents MCQs With Answer provides M.Pharm students with a focused revision tool on experimental approaches used to evaluate lipid‑lowering and diuretic candidates. This set emphasizes mechanistic assays (e.g., HMG‑CoA reductase inhibition), in vivo hyperlipidemia models (e.g., Triton WR‑1339, high‑fat diet, tyloxapol), and diuretic screening protocols (e.g., saline‑loaded rats, lithium clearance, furosemide and thiazide reference models). Questions cover choice of controls, biochemical and physiological endpoints (serum lipids, urinary volume, Na+/K+ excretion, osmolality), interpretation of results, and limitations of each method. The MCQs are designed to deepen understanding of experimental design, data interpretation, and selection of appropriate models for preclinical pharmacological screening.

Q1. Which of the following in vivo models is commonly used to produce acute hyperlipidemia for screening antidyslipidemic agents by blocking peripheral lipoprotein lipase?

• Triton WR-1339 (tyloxapol) induced hyperlipidemia
• High‑fat diet induced chronic hyperlipidemia
• ApoE knockout mouse model
• Streptozotocin-induced diabetic model

Correct Answer: Triton WR-1339 (tyloxapol) induced hyperlipidemia

Q2. Which in vitro biochemical assay is most directly indicative of an agent’s potential to inhibit cholesterol biosynthesis?

• HMG-CoA reductase inhibition assay
• Lecithin–cholesterol acyltransferase (LCAT) assay
• Pancreatic lipase inhibition assay
• Acyl‑CoA:cholesterol acyltransferase (ACAT) assay

Correct Answer: HMG-CoA reductase inhibition assay

Q3. In the Triton WR‑1339 model, which serum parameter shows a rapid and marked increase useful for screening lipid‑lowering drugs?

• Serum triglycerides and total cholesterol
• Serum HDL cholesterol selectively
• Serum creatinine
• Serum transaminases (AST/ALT)

Correct Answer: Serum triglycerides and total cholesterol

Q4. Which reference drug is most appropriate as a positive control when screening HMG‑CoA reductase inhibitors in animal models?

• Atorvastatin
• Gemfibrozil
• Orlistat
• Niacin (nicotinic acid)

Correct Answer: Atorvastatin

Q5. Tyloxapol (Triton WR‑1339) produces hyperlipidemia primarily by which mechanism?

• Inhibition of lipoprotein lipase and blocking clearance of triglyceride‑rich particles
• Increasing hepatic cholesterol synthesis via SREBP activation
• Enhancing intestinal cholesterol absorption
• Direct inhibition of HMG‑CoA reductase

Correct Answer: Inhibition of lipoprotein lipase and blocking clearance of triglyceride‑rich particles

Q6. For evaluating diuretic activity in rats, which primary endpoint is measured in a saline‑loaded acute model?

• Urine volume and urinary electrolyte (Na+, K+) excretion
• Serum cholesterol levels
• Fecal fat excretion
• Blood glucose concentration

Correct Answer: Urine volume and urinary electrolyte (Na+, K+) excretion

Q7. Which screening method best distinguishes between carbonic anhydrase inhibitors and loop diuretics pharmacologically?

• Measurement of urine pH and bicarbonate excretion
• Assessment of serum LDL cholesterol
• HMG‑CoA reductase activity assay
• Oral fat tolerance test

Correct Answer: Measurement of urine pH and bicarbonate excretion

Q8. In diuretic screening using lithium clearance, an observed reduction in fractional Na+ excretion after test drug administration suggests what mechanism?

• Distal tubular sodium reabsorption (e.g., amiloride‑like) action
• Inhibition of carbonic anhydrase in proximal tubule
• Inhibition of Na+-K+-2Cl− cotransporter in thick ascending limb
• Osmotic diuresis due to mannitol‑like effect

Correct Answer: Distal tubular sodium reabsorption (e.g., amiloride‑like) action

Q9. Which experimental model is most suitable for evaluating chronic lipid‑lowering effects and atherogenic changes?

• Long‑term high‑fat/high‑cholesterol diet in rabbits or rodents
• Single dose Triton WR‑1339 acute model
• Acute saline‑loaded rat diuresis model
• Isolated perfused liver HMG‑CoA assay

Correct Answer: Long‑term high‑fat/high‑cholesterol diet in rabbits or rodents

Q10. Which parameter is most indicative of natriuretic (sodium‑excreting) effect rather than a pure osmotic diuresis?

• Significant increase in urinary sodium excretion with corresponding reduction in serum sodium
• Increase in urine volume without change in urinary sodium concentration
• Marked increase in urinary glucose
• Large increase in urine osmolality

Correct Answer: Significant increase in urinary sodium excretion with corresponding reduction in serum sodium

Q11. When screening antidyslipidemic agents, which lipid fraction change is most important to assess cardioprotective potential?

• Increase in HDL and decrease in LDL cholesterol
• Increase in VLDL only
• Reduction in fecal bile acid excretion
• Increase in triglycerides alone

Correct Answer: Increase in HDL and decrease in LDL cholesterol

Q12. The furosemide‑induced diuresis model primarily tests drugs acting on which renal transporter?

• Na+-K+-2Cl− cotransporter in the thick ascending limb of Henle
• Na+/H+ exchanger in the proximal tubule
• NCC (Na+-Cl− cotransporter) in distal convoluted tubule
• Epithelial sodium channel (ENaC) in the collecting duct

Correct Answer: Na+-K+-2Cl− cotransporter in the thick ascending limb of Henle

Q13. In antidyslipidemic screening, inhibition of pancreatic lipase would most likely reduce which endpoint?

• Intestinal triglyceride absorption leading to reduced postprandial triglycerides
• Hepatic cholesterol synthesis measured by HMG‑CoA activity
• HDL particle formation in plasma
• Bile acid synthesis in liver

Correct Answer: Intestinal triglyceride absorption leading to reduced postprandial triglycerides

Q14. Which control drug is most appropriate when validating a thiazide‑type diuretic screening protocol?

• Hydrochlorothiazide
• Furosemide
• Amiloride
• Acetazolamide

Correct Answer: Hydrochlorothiazide

Q15. A novel compound increases HDL‑C but also raises triglycerides in screening. What additional assay would help clarify mechanism?

• Assessment of CETP (cholesteryl ester transfer protein) activity
• Lithium clearance test
• Urine bicarbonate measurement
• Pancreatic amylase activity

Correct Answer: Assessment of CETP (cholesteryl ester transfer protein) activity

Q16. Which limitation is commonly associated with the Triton WR‑1339 model when extrapolating to chronic human dyslipidemia?

• It produces acute hyperlipidemia by blocking lipolysis, not by chronic metabolic dysregulation
• It selectively increases HDL but not LDL
• It does not alter serum triglycerides
• It causes permanent liver injury in all species

Correct Answer: It produces acute hyperlipidemia by blocking lipolysis, not by chronic metabolic dysregulation

Q17. During diuretic screening, a drug causes increased urinary potassium loss. Which class likely produces this effect?

• Loop diuretics and thiazides
• Potassium‑sparing diuretics (amiloride, spironolactone)
• Carbonic anhydrase inhibitors only
• Osmotic diuretics exclusively

Correct Answer: Loop diuretics and thiazides

Q18. For preclinical screening of agents intended to increase reverse cholesterol transport, which measurement is most relevant?

• Cholesterol efflux capacity from macrophages to HDL
• Urinary sodium excretion
• Serum creatinine clearance
• Intestinal glucose absorption

Correct Answer: Cholesterol efflux capacity from macrophages to HDL

Q19. Which experimental observation would indicate that a tested diuretic acts primarily in the proximal tubule?

• Increased urinary bicarbonate and elevated urine pH consistent with carbonic anhydrase inhibition
• Marked natriuresis with low urinary bicarbonate change
• Strong K+ retention with minimal Na+ loss
• Increase in urine glucose excretion

Correct Answer: Increased urinary bicarbonate and elevated urine pH consistent with carbonic anhydrase inhibition

Q20. Which combination of endpoints best differentiates loop diuretic action from thiazide action in acute animal screening?

• Greater natriuresis and diuresis, pronounced inhibition of concentrating ability (lower urine osmolality) for loop diuretics versus moderate natriuresis for thiazides
• Increase in serum HDL for loop diuretics and reduction of LDL for thiazides
• Selective increase in urinary bicarbonate for loop diuretics and decrease for thiazides
• Significant increase in fecal fat excretion with loop diuretics only

Correct Answer: Greater natriuresis and diuresis, pronounced inhibition of concentrating ability (lower urine osmolality) for loop diuretics versus moderate natriuresis for thiazides

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