Christian de Duve glucagon was the major hormone influencing the breakdown of glycogen (glycogenolysis) in the liver, by which more sugars are produced in the blood. De Duve's original hypothesis that glucagon was produced by pancreatic alpha cells was proved right when it was demonstrated that selectively cobalt-damage alpha cells stopped producing glucagon in guinea pigs, and finally isolated the purified hormone in 1953, including those from birds. De Duve was the first to hypothesise that production of insulin to decrease blood sugar level stimulated the uptake of glucose in the liver, and that there is a balanced production of insulin and glucagon
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