Question

Why is insulin not administered orally to a diabetic patient?

• A. Insulin can harm digestive tract if taken orally
• B. Insulin is a peptide hormone
• C. Insulin will lead to sudden hypoglycemia if taken orally
• D. Insulin will break down in buccal cavity only

Answer 1

The correct option is B Insulin is a peptide hormone

Insulin has two polypeptides, A and B chains linked together by disulphide bridges. It cannot be administered orally to diabetic patients as it gets digested by the action of proteolytic enzymes released into the stomach and small intestine. Insulin is therefore taken via injection.

Insulin does not break down in the buccal cavity because proteases are absent in the buccal cavity.
Insulin injection may cause hypoglycemia, i.e., fall in the sugar level of blood. However, drop in sugar level is not related to the oral intake of insulin.