Final answer:
The pancreatic duct does not transport insulin into the duodenum; instead, it carries enzymes like amylase, lipase, and protease which aid in digestion.
Step-by-step explanation:
The pancreatic duct transports a variety of substances into the duodenum, but it does not transport insulin. Insulin is a hormone that is produced by the pancreatic islet cells and is secreted directly into the bloodstream, not into the digestive tract. The pancreatic duct does transport digestive enzymes such as amylase, which is involved in carbohydrate digestion, lipase, which is involved in fat digestion, and protease (referred to in the question as proteinase), which is involved in protein digestion. It carries enzymes that aid in digestion, such as pancreatic amylase, lipase, and proteinase. However, insulin is not transported through the pancreatic duct. Instead, it is released into the bloodstream by pancreatic islet cells to regulate blood sugar levels.