Regulation of insulin secretion: the role of second messengers

This review summarises briefly studies performed in the last 5-6 years concerning the role of second messengers in the regulation of insulin secretion, using intact and electrically permeabilized rat islets of Langerhans. It is concluded that cyclic AMP (through protein kinase A), calcium (through calcium-calmodulin dependent protein kinases) and diacylglycerol (through protein kinase C) may be important second messengers in modulating the effects of specific secretagogues on insulin release. However, recent studies strongly suggest that neither protein kinase A nor protein kinase C are directly involved in the regulation of insulin secretion by glucose. The possible involvement of other second messengers, nitric oxide and arachidonic acid, in the regulation of secretion is also briefly reviewed.