This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Epalrestat is an ? 
Select and explain. 
A. Aldolasereductase inhibitor, B. Fructose cogener, C. Glucose receptor blocker, D. Glucose reuptake activator
A: Aldolasereductase inhibitor
Answer: A: Aldolasereductase inhibitor 
Explanation: Ans. is 'a' i.e., Aldolasereductase inhibitor Aldose reductase, is an enzyme that is normally present in many other pas of the body, and catalyzes one of the steps in the sorbitol(polyol) pathway that is responsible for fructose formation from glucose. Aldose reductase activity increases as the glucose concentration rises in diabetes in those tissues that are not insulin sensitive, which include the lenses, peripheral nerves and glomerulus. Aldose reductase inhibitors are a class of drugs being studied as a way to prevent eye and nerve damage in people with diabetes. Examples of aldose reductase inhibitors include :- Tolrestat (withdrawn from market) Epalrestat Ranirestat Fidarestat