The control of insulin release by sugars.

The interaction of glucose, the major physiological regulator of insulin secretion, with the beta-cell involves the recognition of glucose as a signal, the transduction of this recognition into an intracellular event and the coupling of the event to the exocytotic discharge of insulin from secretory granules. The following aspects of this system are discussed: (1) the mechanism of insulin release; (2) the evidence implicating Ca2+ and cyclic AMP as coupling factors; (3) the main characteristics of glucose-stimulated insulin release; (4) gluco-receptor models and the evidence for them; (5) possible mechanisms for transduction of the response to glucose; (6) the extent to which the systems of the secretory response to sugars may also be involved in the control of proinsulin biosynthesis; (7) whether starvation induces specific changes in the glucoreceptor system.