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 resistance associated with excess body weight. A possible explanation is that both insulin resistance and obesity often have the same cause, systematic overeating, which has the potential to lead to insulin resistance and obesity due to repeated administration of excess levels of glucose, which stimulate insulin secretion; excess levels of fructose, which raise triglyceride levels in the bloodstream; and fats, which may be absorbed easily by the adipose cells, and tend to end up as fatty tissue in a hypercaloric diet. Some scholars go as far as to claim that neither insulin resistance, nor obesity really are metabolic disorders "per se",