All cells of your body need glucose to fulfill their energy needs. For their proper functioning, the body has to maintain the levels of glucose in your blood within a normal range. While too little blood glucose can exhaust your cells, too much glucose in the blood can also damage them. The pancreas plays a primary role in maintaining normal levels of blood glucose by secreting insulin and glucagon. Together, these two hormones allow you to store energy when you eat and efficiently spend it during muscular and mental exercise. Abnormally low or high levels of glucose usually imply a health problem.
Insulin
Insulin is a hormone made in the beta cells of your pancreas. When you eat a meal rich in sugars, insulin causes the utilization of blood glucose by your body cells and is also responsible for storing the surplus energy as glycogen in the muscles and liver. Interestingly, once your blood glucose reaches the desired levels, insulin generation is reduced by the pancreas to avoid hypoglycemia (low blood glucose). If you have diabetes, in which the body's generation or recognition of insulin is ineffective, normal blood glucose levels need continual monitoring. Your physician may prescribe injections of insulin to help you utilize the glucose in your blood.
Glucagon
Glucagon is a hormone made in the alpha cells of your pancreas. Its effect opposes that of insulin. While insulin decreases the levels of glucose in your blood, glucagon breaks down glycogen in the liver to increase the levels of blood glucose. Glucagon is produced in considerable amounts when you exercise and your blood glucose levels are therefore lower than what they should be. Once the glucose in your blood has increased to the desired levels, glucagon generation is reduced by the pancreas as a feedback step. The American Diabetes Association says that diabetes patients facing an insulin reaction (low blood sugar) may need a glucagon injection in a medical emergency.
Other hormones
Besides the above hormones, the body has alternate means to prevent blood glucose from falling too much. A review article published in the American Journal of Physiology -- Endocrinology and Metabolism in 2009 summarizes that catecholamines, cortisol and growth hormone can save the body from extremely low levels of glucose when insulin and glucagon have been unsuccessful in maintaining normal glucose levels.
References
- "Four grams of glucose"; Am J Physiol Endocrinol Metab; D Wasserman; 2009
- American Diabetes Association: Hypoglycemia (Low blood glucose)
