How is blood glucose concentration controlled by hormones?

The three main hormones to consider are: insulin, glucagon, and adrenaline. All three act on receptors on their target cells. Insulin results in the mobilisation of channel proteins in cell vesicles that are then put into the membrane to uptake glucose (GLUT4 in muscle cells, for example, via a cAMP cascade). This allows more glucose to come into the cell, from the blood, reducing blood glucose levels. Insulin also activates enzymes that convert glucose into glycogen, allowing the body to store glucose. This allows the cell to maintain a concentration gradient for glucose, thus more can move into the cell. This occurs in the fed state. Glucagon does the reverse of insulin, activating enzymes that convert glycogen to glucose (glycogenolysis), and also enzymes that convert glycerol and amino acids into glucose. Glucagon is primarily concerned with increasing blood glucose levels, released in the fasting state. Adrenaline activates enzymes involved in converting glycogen to glucose, allowing blood glucose to increase so that the amount of glucose available to use by muscles during a fight or flight response is increased.