It's important that glucose levels in the blood are kept at a constant, as glucose is a key component for cell respiration. The mechanisms for glucose regulation involve the hormones insulin and glucagon. If glucose levels are too high, insulin is secreted from the pancreas into the blood. Insulin causes glucose to move from the blood into muscle and liver cells, glucose is then converted into glycogen (the storage form of glucose) in the liver. This results in the decrease of blood glucose levels to normal. If glucose levels are too low, glucagon is secreted from the pancreas into the blood. Glucagon causes glycogen to be converted to glucose in the liver, glucose is then transported from muscle and liver cells into the blood. This results in blood glucose levels increasing to normal.