Pancreatic δ-cells
A: pancreatic δ-cells receive input from numerous paracrine, endocrine, and neural inputs, and translate this into appropriate inhibition of glucagon and insulin release by α- and β-cells. Select stimulatory and inhibitory inputs are given for each of the islet cell types. B: schematic representation of the profiles of insulin, glucagon, and somatostatin secretion as a function of blood glucose.