Processes that can shed light on the release of the blood sugar-lowering hormone insulin and thus act as a potential target for developing improved diabetes treatment are being detailed by a new study.
Cyclic AMP (cAMP) is a universal messenger molecule that plays a vital role in the release of insulin from the beta cells in the pancreas and production of cAMP explains how certain hormones can amplify insulin secretion.
The team led by Anders Tengholms at Uppsala University has developed methods that can help in measuring both the secretion of insulin and the cAMP concentration in individual beta cells.
The discovery was based on the development of image analysis methods that make possible the detailed study of events immediately inside the plasma membrane of the insulin-secreting cells.
The results show that ATP, the energy-rich molecule that is produced when glucose is metabolized, causes an increase in cAMP concentration right at the cell membrane where the release of insulin takes place.
This increase varies rhythmically and coincides with similarly regular variations in another stimulant messenger, the calcium ion, resulting in pulsatile secretion of insulin.
Tengholm said that optimal glucose-induced insulin secretion requires that the varying cAMP and calcium signals are coordinated in time.
The new study helps in understanding the cellular mechanisms that underlie the pulsatile release of insulin in healthy individuals.
The connection between metabolism and cAMP is not only important for the secretion of insulin; it also plays a role in gene regulation, cell growth, and cell survival.
The observations thereby pave the way for understanding of the disturbed beta cell function in type 2 diabetes and for the development of new drugs for the disease.