Which hormone is primarily responsible for stimulating bile secretion in the liver?

Cholecystokinin is the hormone primarily responsible for stimulating bile secretion from the liver. When fatty acids and amino acids enter the small intestine, they trigger the release of cholecystokinin from the intestinal cells. This hormone not only stimulates the gallbladder to contract and release stored bile but also promotes the secretion of bile from the liver. Bile is crucial for the digestion and absorption of dietary fats.

In addition to its role in bile secretion, cholecystokinin also slows gastric emptying and enhances the secretion of digestive enzymes from the pancreas, thereby playing a significant role in digestion. Understanding the function of cholecystokinin is essential in recognizing how the body regulates digestion and bile production in response to nutrient intake.

Other hormones, while important in the digestive process, do not primarily stimulate bile secretion. Insulin plays a key role in glucose metabolism, gastrin primarily stimulates gastric acid secretion, and secretin's main function relates to regulating water homeostasis and stimulating bicarbonate secretion from the pancreas to neutralize stomach acid in the small intestine. Thus, cholecystokinin stands out as the central hormone for bile secretion from the liver.