Which hormone stimulates bile release and pancreatic enzyme secretion in response to fat in the duodenum?

Which hormone stimulates bile release and pancreatic enzyme secretion in response to fat in the duodenum?

• A. GIP
• B. Secretin
• C. Motilin
• D. CCK

Answer: (D)

When fatty chyme enters the duodenum, the intestinal cells called I cells release cholecystokinin. This hormone is the signal that fats are present and need to be processed. Cholecystokinin causes the gallbladder to contract, pushing bile into the duodenum where it emulsifies fats, and it also stimulates the pancreatic acinar cells to secrete enzyme-rich juice, including lipase, into the intestine to digest fats and other nutrients. It even helps by relaxing the sphincter of Oddi so these secretions can flow into the duodenum. The other hormones have different primary roles, which is why they don’t fit this scenario as directly. GIP mainly promotes insulin release in response to glucose and fats and slows gastric activity. Secretin is focused on stimulating bicarbonate-rich pancreatic juice to neutralize acid in the intestine, signaling a different aspect of digestion. Motilin mainly regulates gut motility rather than secretion of bile or digestive enzymes. So the one that best explains bile release and pancreatic enzyme secretion in response to fat in the duodenum is cholecystokinin.

When fatty chyme enters the duodenum, the intestinal cells called I cells release cholecystokinin. This hormone is the signal that fats are present and need to be processed. Cholecystokinin causes the gallbladder to contract, pushing bile into the duodenum where it emulsifies fats, and it also stimulates the pancreatic acinar cells to secrete enzyme-rich juice, including lipase, into the intestine to digest fats and other nutrients. It even helps by relaxing the sphincter of Oddi so these secretions can flow into the duodenum.

The other hormones have different primary roles, which is why they don’t fit this scenario as directly. GIP mainly promotes insulin release in response to glucose and fats and slows gastric activity. Secretin is focused on stimulating bicarbonate-rich pancreatic juice to neutralize acid in the intestine, signaling a different aspect of digestion. Motilin mainly regulates gut motility rather than secretion of bile or digestive enzymes. So the one that best explains bile release and pancreatic enzyme secretion in response to fat in the duodenum is cholecystokinin.