Glucose Some glucose is converted to lactic acid by astrocytes, which is then utilized as an energy source by brain cells; some glucose is used by intestinal cells and red blood cells, while the rest reaches the liver, adipose tissue and muscle cells, where it is absorbed and stored as glycogen (under the influence of insulin). Liver cell glycogen can be converted to glucose and returned to the blood when insulin is low or absent; muscle cell glycogen is not returned to the blood because of a lack of enzymes. In fat cells, glucose is used to power reactions that synthesize
Glucose 6-phosphatase variety of muscles across the animal kingdom, albeit at very low concentrations. Thus, the glycogen that muscles store is not usually available for the rest of the body's cells because glucose-6-phosphate cannot cross the sarcolemma unless it is dephosphorylated. The enzyme plays an important role during periods of fasting and when glucose levels are low. It has been shown that starvation and diabetes induces a 2-3-fold increase in glucose-6-phosphatase activity in the liver. Glc 6-Pase activity also increases dramatically at birth when an organism becomes independent of the mothers source of glucose. The human Glc 6-Pase gene contains five exons