Insulin

When blood glucose levels rise after a meal, insulin allows glucose to be taken up by the body's cells, especially muscle and fat cells, where is it is used for energy production. Insulin then signals to the liver to store the remaining excess blood glucose as carbohydrates and fat, as a form of energy storage.

Humans need insulin on a daily basis to survive. Without insulin, glucose cannot reach most of the body's cells. Without glucose, the cells starve, and blood glucose levels rise to dangerous levels. Eventually, very high glucose levels lead to a life-threatening condition called a diabetic coma.

People with type 1 diabetes produce very little insulin and must take daily insulin injections. People with type 2 diabetes can usually produce insulin but may need oral medications that increase their body's cells response to insulin (the cells may become resistant over time and/or with obesity) or that stimulate he pancreas to produce more insulin. In many cases people with type 2 diabeties may also need to take insulin injections to achieve normal glucose levels.

Insulin and glucose levels must be in balance. An excess amount of insulin in the blood is known as 'hyperinsulinaemia'. This is most often seen with insulinomas (insulin-producing tumours) or with an excess amount of injected insulin, and can be dangerous. It causes hypoglycaemia (low blood glucose levels), which can lead to sweating, rapid heart beat, hunger, confusion, visual problems, and seizures. Since the brain is totally dependent on blood glucose as an energy source, glucose deprivation due to hyperinsulinaemia can lead fairly quickly to death.