English: The liver (and glycogen stored in the liver) plays an important role in the maintenance of the blood sugar levels. The blood concentration of glucose is about 5 mM. When blood sugar is high, insulin is released from the pancreas. Insulin stimulates glucose uptake by many tissues and stimulates glycogen synthesis via binding to an insulin receptor and control of protein kinases and PP1. When blood sugar is low, the pancreas releases glucagon into the bloodstream. This triggers the stimulation of glycogen breakdown, leading to increased glucose-6-phosphate levels. After dephosphorylation by the enzyme glucose-6-phosphatase (an enzyme that is absent in most other tissues), glucose leaves the liver and enters the bloodstream.