Insulin signal transduction pathway is secreted after glucose enters the beta cell and that triggers several other processes in a chain reaction. While insulin is secreted by the pancreas to lower blood glucose levels, glucagon is secreted to raise blood glucose levels. This is why glucagon has been known for decades as a counter-regulatory hormone. When blood glucose levels are low, the pancreas secretes glucagon, which in turn causes the liver to convert stored glycogen polymers into glucose monomers, which is then released into the blood. This process is called glycogenolysis. Liver cells, or hepatocytes, have glucagon receptors which allow for glucagon to attach
Glucose major facilitator superfamily. In the small intestine (more precisely, in the jejunum), glucose is taken up into the intestinal epithelial cells with the help of glucose transporters via a secondary active transport mechanism called sodium ion-glucose symport via the sodium/glucose cotransporter 1. The further transfer occurs on the basolateral side of the intestinal epithelial cells via the glucose transporter GLUT2, as well as their uptake into liver cells, kidney cells, cells of the islets of Langerhans, nerve cells, astrocytes and tanyocytes. Glucose enters the liver via the vena portae and is stored there as a cellular glycogen. In the liver