What hormone triggers the release of pancreatic juice rich in HCO3^-?

The hormone secretin triggers the release of bicarbonate-rich pancreatic juice to neutralize the acidic chyme in the duodenum. It works in conjunction with cholecystokinin (CCK), which stimulates the production of enzyme-rich pancreatic juice for digestion of proteins and fats.

Explanation:

The hormone that triggers the release of pancreatic juice rich in HCO3- (bicarbonate ions) is secretin.

When the acidic chyme from the stomach enters the duodenum, it stimulates the duodenal cells to release secretin into the bloodstream.

In response to secretin, the exocrine portion of the pancreas secretes a bicarbonate-rich pancreatic juice, which helps neutralize the acidity of the intestinal contents and provides an optimal pH for digestive enzymes to function.

In tandem with secretin, another hormone called cholecystokinin (CCK) also plays a role in pancreas stimulation.

CCK is responsible for stimulating the pancreas to produce enzyme-rich pancreatic juice, which aids in the digestion of proteins and fats, and it also enhances the action of secretin.