Research undertaken at the Wake Forest Baptist Medical Center have discovered that a protein plays a critical role in blood sugar regulation and diabetes.
The hope is that this new protein can be used to treat type I Diabetes.
The pancreas is the key organ in the regulation of blood sugar levels – it is an endocrine and exocrine gland. The endocrine parts are known as Islets of Langerhans, they are responsible for the release of various hormones such as: insulin, glucagon, somatostatin, pancreatic polypeptide and so on.
In healthy individuals insulin’s role is to activate the GLUT-4 transporter and speed up glucose uptake into cells (it is also a very anabolic hormone and a proteosome inhibitor). Insulin is secreted by Beta cells in the Islets of Langerhans.
In healthy people glucagon’s role is to increase blood sugar by stimulating the break down of glycogen stores in the muscles and liver after binding to the glucagon receptor. These two hormones work antagonistically and when one is elevated the other is decreased. Glucagon is secreted by Alpha cells in the Islets of Langerhans.
Somatostatin is a hormone that inhibits the effects of growth hormones and is generally more active during the day than at night. Somatostatin is produced in the Delta cells of the Islets of Langerhans.
Diabetes type I is thought to be caused by viruses or environmental triggers which cause the death of alpha cells leading to no insulin production in the body. As a result glucose cannot be stored as quickly and efficiently and there is no inhibition of glucagon synthesis. This causes hyperglycaemia and results in the high blood glucose levels that diabetics have. One of the most common treatments is to use insulin injections which can carry a large risk of hypoglycaemic coma.
The protein that the researchers are working with has been named as, Islets Homeostasis Protein (IHoP) and is specifically found in the glucagon-producing cells (Alpha cells). In humans and mice (both used in this study), diabetics showed no IHoP present whereas, healthy people produced an abundance of IHoP.
The thinking is that this protein may be a key control mechanism in the regulation of the balance between insulin and glucagon hormone levels.
During the research scientists inhibited production of IHoP in healthy mice and noticed a large drop in glucagon hormone levels. The chain of events following this was a decrease in insulin, the death of Beta cells (insulin secreting cells) and finally a large increase in glucagon levels.
This research provides a great opportunity for further research. If researchers can prove the link between IHoP and the regulation of glucagon hormone and insulin hormone levels, then gene therapy can be trialed to reactivate the gene that expresses IHoP. This could in the future provide a cure for Diabetes type I.