REGULATION OF INSULIN-SECRETION - THE ROLE OF 2ND-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 d iacylglyceror (through protein kinase C) may be important second messe ngers in modulating the effects of specific secretagogues on insulin r elease. 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 sec ond messengers, nitric oxide and arachidonic acid, in the regulation o f secretion is also briefly reviewed.