Glucose-1-phosphate (G1P) is an important carbohydrate intermediate in glucose metabolism and storage. In response to hormonal or neural signals, glycogenolysis occurs in liver and muscle tissues where Glucose-1-phosphate is released as the rate-limiting step in glycogen breakdown. Glucose-1-phosphate is subsequently converted to Glucose-6-phosphate by phosphoglucomutase and enters glycolysis. In glycogen synthesis, glucose is transferred to glycogen through the actions of Phosphoglucose isomerase (G6P ? G1P), UDPG-pyrophosphorylase (G1P ? UDP-glucose) and glycogen synthase (UDP-glucose + glycogen[n] ? UDP + glycogen[n+1]). Glucose-1-phosphate is found in virtually all organisms from bacteria to higher plants and animals. Measurement of int