A chemical which stimulates the secretion of pepsin is

We need to identify the chemical that stimulates the secretion of pepsin.

Understanding pepsin secretion

Pepsin is a digestive enzyme secreted by the chief cells of the gastric glands in the stomach. The secretion of gastric juice (which contains pepsin and HCl) is stimulated by histamine.

Role of histamine

Histamine binds to $$H_2$$ receptors on the parietal cells and chief cells of the stomach lining. This binding stimulates the secretion of:

- Hydrochloric acid (HCl) from parietal cells

- Pepsinogen (inactive form of pepsin) from chief cells

Checking other options

- Cimetidine (Option B): This is an antihistamine ($$H_2$$ receptor antagonist) that inhibits acid secretion, not stimulates it.

- Zantac (Option C): This is the brand name for ranitidine, another $$H_2$$ receptor antagonist that reduces stomach acid production.

- Antihistamine (Option D): These are drugs that block the action of histamine, thus reducing secretion.

The correct answer is Option A: Histamine.