hormone

Glucagon

Glucagon is a pancreatic hormone that helps maintain blood glucose during fasting and between meals.

Alpha cells release glucagon, which acts especially on the liver to promote glucose production and release when blood glucose is low.

A counter-regulatory signal

Glucagon binds receptors on liver cells and promotes glycogen breakdown and gluconeogenesis, helping make glucose available between meals. Its effect depends on nutritional and hormonal context; it is not simply an “opposite” switch that explains every blood-glucose change.

Related topics

  • Glucagon helps maintain availability of Glucose

    Glucagon acts mainly on the liver to support glucose production and release between meals.

Worth knowing

  • It acts mainly through the liver. The liver is a major target for glucagon’s glucose-regulating actions; muscle does not release its glycogen into blood in the same way.

A closer look

Several signals regulate secretion

Glucagon secretion is influenced by blood glucose, amino acids and other pancreatic signals; hepatic glycogen breakdown and gluconeogenesis then affect glucose availability.

References

Source-checked local draft.
Human editorial review pending.

  1. NIH National Library of MedicinePhysiology, Endocrine HormonesChecked 2026-09-05
  2. NIH National Institute of Diabetes and Digestive and Kidney DiseasesInsulin Resistance & PrediabetesChecked 2026-09-05