Glucagon

Net effect: increase serum glucose
Secreted from alpha cells pancreas
Stimulus - hypoglycaemia
- metabolic stress
- catecholamines/sympathetic nervous system ++
- ↑ circulating amino acids
Inhibition - hyperglycaemia
- insulin
- somatostatin
- ↑ free fatty acids, keto acids
Site of action G-protein coupled receptors → activates adenylyl cyclase in hepatocytes → ↑ cAMP in liver (etc)
Action ⊕ gluconeogenesis, glycogenolysis, ketogenesis, lipolysis, hepatic urea synthesis
⊖ glycolysis
Inhibits small intestine motility
Stimulates bile formation

clinical application

Exogenous glucagon used for Beta blocker toxicity

Cautions

  • Glucagonoma
  • Ineffective in chronic hypoglycaemia, starvation, and adrenal insufficiency
  • Insulinoma

contraindications

  • phaeochromocytoma

Insulin physiology | endocrine pancreas

#endocrine #glucose-homeostasis