Hormones help your body run like a fine-tuned machine. Without them, your body would not be able to properly function the way it does. The hormone insulin is especially important because it helps to move glucose into your cells to use for energy. Insulin is only there when your body needs it and acts as a facilitator for both glucose and amino acids to move into your tissues.
Insulin
Insulin is a hormone your body uses to regulate your blood glucose and clear it out after a meal. Its role is to stimulate your cells to take in glucose and either use it or store it for later. When insulin is in your blood, the mechanisms to make glycogen, fat and proteins are also stimulated. It is for this reason that insulin is also equated to promoting cellular growth and differentiation. Increased levels of blood insulin also inhibit the release of fat for energy.
Mechanism of Action
Insulin helps to facilitate the movement of glucose into cells. Your cells have insulin receptors located on the outside of the membrane. These receptors become activated when insulin is circulating through the bloodstream. When insulin binds to the receptor on the cell, it initiates a cascade of reactions to stimulate uptake of glucose by the cell. GLUT-4, the glucose transporter, is also located on the outside of the cell and is stimulated to take in glucose, once insulin is received.
Insulin Production and Regulation
Your body works in a manner of supply and demand. Your pancreas is signaled to produce and excrete insulin during periods of elevated blood glucose. The beta cells of the islets of your pancreas secrete insulin when needed. In times of low blood glucose, though, insulin secretion is inhibited. Instead, glucagon is excreted by your pancreas. Glucagon does the opposite job of insulin; it actually stimulates your body to make glucose and break down fat.
Complications
For some people, the mechanism of insulin does not work effectively. Diabetes is a disease characterized by the body's inability to either produce insulin or recognize it in the bloodstream. There are two main types of diabetes: type 1 and type 2. Type 1 diabetics have problems making insulin. Type 2 diabetes occurs when your cells become insulin resistant and glucose is unable to enter into the cells. Type 1 diabetes can usually be controlled with regular insulin medication. Type 2 diabetes can also be controlled with medication, but can also be avoided by controlling your weight and diet and exercising regularly.
References
- endocrineweb; Diabetes; What is Insulin?; James Norman MD, FACS, FACE; March 29, 2009
- Colorado State University: Physiologic Effects of Insulin
- "Anatomy and Physiology"; Kenneth S. Saladin; 2004
- "Exercise Physiology"; George A. Brooks, et al.; 2005
- National Diabetes Information Clearinghouse; Diabetes Overview
