Figure 1.

Dose–response relationships for glucose-regulated secretion of glucagon, insulin, and somatostatin. Batches of mouse islets were incubated for 60 min with glucose concentrations ranging from 0 to 30 mM. Glucagon secretion is expressed in per cent of that stimulated by absence of glucose, whereas insulin and somatostatin secretion are expressed in per cent of that stimulated by 30 mM glucose. Mean values ± SEM for eight experiments. The illustration is essentially based on data, from Vieira et al. 2007 (40), combined with data at 25 and 30 mM glucose that were not included in the original publication. Glucagon secretion at >20 mM glucose exceeds that stimulated by the absence of sugar.