What best describes insulin?

• A. A natural hormone produced by the pancreas.
• B. A recombinant DNA drug product (protein) approved by the FDA.
• C. A carbohydrate involved in regulating blood sugar.
• D. A lipid molecule used for energy storage.

Answer: (B)

Insulin is a peptide hormone that regulates blood glucose, produced naturally by the beta cells of the pancreas. In medicine, the insulin used for treatment is manufactured using recombinant DNA technology to produce human insulin or insulin analogs, and these products are approved by the FDA. This combination of being a protein drug created through recombinant methods and having formal regulatory approval makes the description of insulin as a recombinant DNA drug product the most accurate for therapeutic use. It is not a carbohydrate or a lipid, and while the body makes it naturally, the clinically used form is the biotech-produced protein drug.