Insulin signal transduction pathway signals the conversion of the glycogen already stored in the liver cells into glucose. This process is called glycogenolysis. Conversely, when the blood-glucose levels are too high, the pancreas is signaled to release insulin. Insulin is delivered to the liver and other tissues throughout the body (e.g., muscle, adipose). When the insulin is introduced to the liver, it connects to the insulin receptors already present, that is tyrosine kinase receptor. These receptors have two alpha subunits (extracellular) and two beta subunits (intercellular) which are connected through the cell membrane via disulfide bonds. When the insulin binds to these alpha subunits,
Insulin in the various signaling pathways by tyrosine phosphatases. Serine/Threonine kinases are also known to reduce the activity of insulin. The structure of the insulin–insulin receptor complex has been determined using the techniques of X-ray crystallography. The actions of insulin on the global human metabolism level include: The actions of insulin (indirect and direct) on cells include: Insulin also influences other body functions, such as vascular compliance and cognition. Once insulin enters the human brain, it enhances learning and memory and benefits verbal memory in particular. Enhancing brain insulin signaling by means of intranasal insulin administration also enhances the acute thermoregulatory