The hormone is synthesized and secreted from alpha cells (α-cells) of the islets of Langerhans, which are located in the endocrine portion of the pancreas.
Production, which is otherwise freerunning, is suppressed/regulated by amylin, a peptide hormone co-secreted with insulin from the pancreatic β cells.
As plasma glucose levels recede, the subsequent reduction in amylin secretion alleviates its suppression of the α cells, allowing for glucagon secretion.

In rodents, the alpha cells are located in the outer rim of the islet.
Human islet structure is much less segregated, and alpha cells are distributed throughout the islet in close proximity to beta cells.
Glucagon is also produced by alpha cells in the stomach.

Recent research has demonstrated that glucagon production may also take place outside the pancreas, with the gut being the most likely site of extrapancreatic glucagon synthesis.
The hormone is synthesized and secreted from alpha cells (α-cells) of the islets of Langerhans, which are located in the endocrine portion of the pancreas. Production, which is otherwise freerunning, is suppressed/regulated by amylin, a peptide hormone co-secreted with insulin from the pancreatic β cells. As plasma glucose levels recede, the subsequent reduction in amylin secretion alleviates its suppression of the α cells, allowing for glucagon secretion.
In rodents, the alpha cells are located in the outer rim of the islet. Human islet structure is much less segregated, and alpha cells are distributed throughout the islet in close proximity to beta cells. Glucagon is also produced by alpha cells in the stomach.
Recent research has demonstrated that glucagon production may also take place outside the pancreas, with the gut being the most likely site of extrapancreatic glucagon synthesis.
Glucagon