Which among the following chemicals is actively involved in hunger and satiety?

Correct option is A

Cholecystokinin (CCK) is a peptide hormone released by the small intestine in response to food intake, particularly fats and proteins. It plays a crucial role in signaling satiety (fullness) to the brain, thereby regulating food intake. CCK acts on both peripheral receptors and central nervous system pathways to reduce appetite and meal size, making it one of the most important satiety signals in the body.

Information Booster:
1. Satiety Signaling: CCK is release from I-cells in the duodenum and jejunum when food enters the small intestine
2. 2. Dual Action: Works peripherally by slowing gastric emptying and centrally by activating vagal afferents that signal the brainstem
3. 3. Digestive Functions: Besides appetite regulation, CCK stimulates pancreatic enzyme secretion and gallbladder contraction
4. 4. Short-term Regulation: Primarily involved in meal-to-meal satiety rather than long-term energy balance (unlike leptin)
5. 5. Clinical Applications: Understanding CCK function has implications for treating eating disorders and obesity

Additional Knowledge:
• Angiotensin (B): Primarily involved in blood pressure regulation and thirst, not hunger/satiety
• Bradykinin (C): A peptide involved in inflammation, pain, and vasodilation
• Histamine (D): Involved in immune responses, allergic reactions, and gastric acid secretion, not primarily hunger regulation