Figure 2.

Hypothetical pathway of glucagon action/modulation on liver. (A) In physiological conditions, blood glucose regulates insulin and glucagon secretion. The equilibrium of these two hormones controls hepatic glucose release. (B) When glucagon is intramuscularly injected, it acts mainly at the hepatic level resulting in the activation of glucose release through glycogen lysis and gluconeogenesis. (C) Nasal glucagon administration could induce actions at the brain levels. In this way, novel potential actions at the hepatic level could regulate hepatic glucose release.