Which of the following substances is secreted by the pancreas?

The substance secreted by the pancreas is insulin. Insulin is a crucial hormone produced by the beta cells of the islets of Langerhans in the pancreas. Its primary role is to regulate blood glucose levels by facilitating the uptake of glucose into cells, thereby lowering blood sugar levels after meals. This function is vital for maintaining energy homeostasis in the body and preventing conditions such as hyperglycemia and diabetes.

Bile, on the other hand, is produced by the liver and stored in the gallbladder, playing a key role in the digestion of fats but is not secreted by the pancreas. Creatinine is a waste product formed from the normal breakdown of muscle tissue and is primarily excreted by the kidneys, not secreted by the pancreas. Hydrochloric acid is secreted by the stomach to aid in digestion and is not associated with pancreatic function. Hence, insulin is the sole substance secreted by the pancreas among the given options.