Secretion from the exocrine pancreas is increased by which hormone?

Cholecystokinin (CCK) is the hormone that plays a crucial role in stimulating secretion from the exocrine pancreas. When food, particularly fats and proteins, enters the duodenum, CCK is released from the intestinal mucosa. This hormone serves to promote the secretion of digestive enzymes from the pancreatic acinar cells, which aids in the digestion of these macronutrients. The presence of CCK also stimulates the gallbladder to contract and release bile, further facilitating fat digestion.

In contrast, gastrin primarily stimulates gastric acid secretion in the stomach rather than pancreatic secretions. Secretin, while it does also influence the pancreas, primarily regulates the secretion of bicarbonate to help neutralize gastric acid in the small intestine. Insulin is a hormone produced by the pancreas that primarily regulates blood glucose levels and does not play a direct role in stimulating exocrine secretion. Therefore, CCK's specific action in enhancing the secretion of digestive enzymes makes it the correct answer to the question.