The Distribution and Structural Characters of Pancreatic Lymphatic Vessels and Its Relationship with Insulin Transport

At present, the intracellular synthesizing process of insulin is very clear, and most of the steps have been illustrated. But there are few researching reports when referring to the physiological transporting route of insulin after it’s secreted into the tissue space. Now it is generally accepted that insulin can be transported by blood after entering into the capillaries in the pancreatic islands, and this route has been proved by several researches. In the normal condition, except for the blood vessels, whether there is other route or not is still disputed at the present time. Early in the last century, many researchers reported the existence of insulin in the thoracic duct lymph of some kinds of animals. This prompts that the lymphatic system of pancreas maybe act an important role in the insulin transport after released into the tissue fluid by the B cells in normal condition. If this route actually exists, it have both physiological and pathological meanings: the insulin transported by the lymphatic vessel can bypass the hepatic portal vein and void the“first pass effect”of liver. So the insulin could enter into the systemic circulation directly and be carried to the target organs all over the body. In some pathological condition, the circulation of pancreatic lymph was hampered, which leading to transporting block of insulin, glucose metabolism disorder may be induced. If this route is true, there is analogy sense for other peptide hormones. In this study, we discussed the distribution of pancreatic lymphatic vessels and the extracellular transporting route in order to ensure the existence of lymphatic route in normal condition. The changes of glucose level after blocking the circulation of lymph was touched on also. The contents and the results were showed below.1.The distribution and structural characters of pancreatic lymphatic vessels in common used rodents