Glucagon Physiology Lecture slidesGlucagon Physiology Lecture slides


Pancreas secretes many hormones which are:

  1. Insulin
  2. Glucagon
  3. Amylin,
  4. Somatostatin, and
  5. Pancreatic polypeptide

The islets of Langerhans, which secrete insulin and glucagon directly into the blood


  • Glycogenolysis
  • Gluconeogenesis
  • Inhibit storage of fats in fat cells
  • Increase Breakdown of stored TGs into FA to release in blood


  • Glucagon in high concentrations also
  • Enhances the strength of the heart;
  • Increases blood flow in some tissues, especially the kidneys;
  • Enhances bile secretion; and
  • Inhibits gastric acid secretion.

Factors that play an important role in Regulation of Glucagon Secretion

  • Increased Blood Glucose Inhibits Glucagon Secretion
  • Increased Blood Amino Acids Stimulate Glucagon Secretion(glucagon then promotes rapid conversion of the amino acids to glucose, thus making even more glucose available to the tissues).
  • Exercise Stimulates Glucagon Secretion (A beneficial effect of the glucagon is that it prevents a decrease in blood glucose).


HormoneReleased fromReleasing factorEffect
InsulinPancreas (b cells)HyperglycemiaPromote glucose utilization
GlucagonPancreas (a cells)HypoglycemiaPromote fat utilization
Growth hormoneAnterior pituitary glandProlonged HypoglycemiaPromote fat utilization
CortisolAdrenal cortexProlonged HypoglycemiaPromote fat utilization
EpinephrineAdrenal medullaHypoglycemia / Stress/exercisePromote fat utilization Lipolytic action+++++Have glycogenolysis +

Liver also play an important role in controlling blood glucose level

Why blood glucose regulation is


Stimulating factorsEffects
Increase blood glucoseIncrease amino acidsIncrease fatty acidsIncrease GI hormones released in response to foodAct on islets of Langerhans and depress the secretion of both insulin and glucagon.Decrease the motility of stomach, duodenum and gallbladder.Decrease    both     the     secretion     and absorption in GIT

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