Which signal is anorexigenic and located in the duodenum?

Which signal is anorexigenic and located in the duodenum?

• A. CCK
• B. Ghrelin
• C. PYY
• D. GLP-1

Answer: (A)

Anorexigenic signals in the gut are those that tell the brain to reduce appetite. In the duodenum, the key signal is cholecystokinin (CCK), released by I-cells when fats and proteins enter this first section of the small intestine. CCK communicates with the brain via vagal pathways to promote fullness and also slows gastric emptying, which helps sustain the feeling of satiety after a meal. Ghrelin, on the other hand, is produced mainly in the stomach and actually stimulates appetite. PYY and GLP-1 do suppress appetite as well, but they are primarily produced further along the gut—in the ileum/colon for PYY and the distal small intestine for GLP-1—so they’re not the duodenal signal described here.

Anorexigenic signals in the gut are those that tell the brain to reduce appetite. In the duodenum, the key signal is cholecystokinin (CCK), released by I-cells when fats and proteins enter this first section of the small intestine. CCK communicates with the brain via vagal pathways to promote fullness and also slows gastric emptying, which helps sustain the feeling of satiety after a meal.

Ghrelin, on the other hand, is produced mainly in the stomach and actually stimulates appetite. PYY and GLP-1 do suppress appetite as well, but they are primarily produced further along the gut—in the ileum/colon for PYY and the distal small intestine for GLP-1—so they’re not the duodenal signal described here.