Blood sugar level In humans, glucose is the primary source of energy, and is critical for normal function, in a number of tissues, particularly the human brain which consumes approximately 60% of blood glucose in fasted, sedentary individuals. Glucose can be transported from the intestines or liver to other tissues in the body via the bloodstream. Cellular glucose uptake is primarily regulated by insulin, a hormone produced in the pancreas. Glucose levels are usually lowest in the morning, before the first meal of the day, and rise after meals for an hour or two by a few millimoles. Blood sugar levels outside the
PYGL glycolysis and other biosynthetic functions for energy metabolism. As the major isozyme in liver, PYGL is responsible for maintaining blood glucose homeostasis by regulating the release of glucose 1-phosphate from liver glycogen stores. One model suggests that Ca oscillations play a role in activating glycogen phosphorylase in glycogen degradation in liver cells. Through its function in the liver, PYGL is also central to meeting the glycemic demands of the entire body. Though other tissues may express all three forms in different proportions, the purpose of expressing multiple glycogen phosphorylases remains unclear. PYGL has been implicated in glycogen storage disease type