Biology Online explains that the body requires glucose in order to create adenosine triphosphate, or ATP. ATP provides the energy that fuels most of the biochemical reactions in the body. Since the demand for ATP fluctuates according to exercise, stress, and other factors, the need for glucose fluctuates, as well. A class of chemical messengers called hormones regulates the amount of glucose circulating in the blood.
Glucagon
The hormone glucagon is made in the alpha cells of the pancreas. When blood glucose gets too low, the alpha cells release glucagon, which causes glycogen to be converted into glucose. The American Diabetes Association explains that glucagon injections are given if blood glucose levels get dangerously low.
Insulin
Insulin is the opposite of glucagon. When levels of glucose get too high, insulin is released from beta cells in the pancreas. The insulin converts glucose back to glycogen.
Type 1 diabetes occurs when the body does not produce enough insulin. Type 2 diabetes occurs when the body does not respond sufficiently to insulin that is produced. Both diseases are associated with high blood sugar.
Other hormones
Other hormones from the adrenal gland and thyroid gland also affect blood glucose levels. WISC.com explains that the hormones epinephrine and cortisol are released from the adrenal glands. Together, these hormones help release glucose from glycogen and antagonize insulin so that blood glucose levels go up. This is useful in times of stress when the body needs more energy.
