Type I diabetes, islets of Langerhans glucagon secretion

A photomicrograph of a section through the pancreas of a patient who has had Type I (early onset) diabetes for 40 years. The section has been immunolabelled for glucagon (brown). It shows how the islet shape has become distorted (imploded) as a result of loss of beta-cells in the acute automimmune destructive phase of the disease: the islet is fliled with non-beta-cells.