Glucagon

General information

Glucagon, which is produced in the alpha cells of the islets of Langerhans, is used in type 1 diabetes mellitus to stimulate glucose output from the liver during hypoglycemia (1 mg subcutaneously, repeated once or twice) when glucose cannot be given intravenously. In some countries it is often used by personnel, such as family members, who are not medically qualified, as the first action when the patient cannot take sugar orally. The antihypoglycemic effect of an intramuscular injection is longer lasting and more potent than that of intravenous glucagon [ ]. It is sometimes given by infusion to treat chronic hypoglycemia. However, when there is insulin reserve in the pancreas, glucagon induces hypoglycemia by stimulating insulin release [ ].

Glucagon has also been used to stimulate secretion of insulin and C peptide, to see whether the islets still produce insulin, as a stimulatory test during pheochromocytoma, hyperinsulinism, and Zollinger–Ellison syndrome, or as an additive in upper gastrointestinal X-ray investigations (0.5–1 mg). It has been used in myocardial infarction, although its inotropic effects may present a risk. It has also been used to treat overdoses with beta-blockers [ ] and calcium channel blockers [ ], although its efficacy in such cases has only been demonstrated in animals [ ] and to treat overdose with tricyclic antidepressants [ , ].

During long-term administration glucagon can cause the same effects as a glucagonoma: hyperglycemia, necrolytic migratory erythema, weight loss, anemia, angular cheilitis, and venous thrombosis [ ].

Glucagon has been used to assess adrenal function in 215 children who had fasted overnight; 79 were aged 0.1–5 years, 28 were aged 5.1–10 years, 96 were aged 10.1–15 years, and 12 were aged over 15 years [ ]. The dose was 0.05 mg/kg (maximum 1.0 mg) subcutaneously. There was nausea in 25% and vomiting in 6%. Walking and drinking water minimized these adverse reactions. No information was given as to whether adverse reactions occurred more often in certain age groups.

Organs and systems