Glucose Homeostasis and Derangement in Birds.

Birds (class Aves) have 1.5 to 2 times higher blood glucose concentrations than mammals of comparable sizes. The reasons for this have been studied and are believed to be multifactorial. There is low expression of insulin receptors, decreased sensitivity of the pancreatic β-cells to glucose, an absent or dysfunctional glucose transporter type 4 pathway, and increased blood glucagon concentrations. Glucagon and somatostatin appear to play a greater role than insulin in glucose homeostasis in birds. Severe hyperglycemia in birds can be attributed to diabetes mellitus, necessitating therapy to prevent short-term and long-term deleterious effects.