Despite records dating back to the 2nd century AD, which show Aretaeus of Cappadocia describing diabetes as a serious disease, treatment was not available until the 20th century, following the discovery of insulin in 1921. Administration of insulin has since not only saved the lives of millions of people but has dramatically improved the quality life for people with diabetes by helping them to control blood glucose levels.
Insulin is a polypeptide hormone synthesised, stored and secreted by the beta cells in the islets of Langerhans situated predominantly in the body and tail of the pancreas. It is released in response to a rising blood glucose level above the normal range of 4-7mmol/l via a pulsing action of the pancreas which is activated 300-400 times per day. It is this pulsing action which enables the pancreas to secrete small amounts of insulin frequently throughout the day and night to control blood glucose levels.