Glucagon- Regulation of Secretion, Pharmacological action, Mechanism of action, Therapeutic uses, Contraindications.

1. Presented by-
Ritesh Rajendra Pandav
pandavritesh@gmail.com
2020-2021
TOPIC- GLUCAGON

2. Glucagon
Glucagon word derived from Greek word glukus (sweet) &
agon (bringing).
Glucagon was discovered by Murlin & Kimball in 1923,
less than 2 years after the discovery of insulin.
It is single chain polypeptide containing 29 amino acid,
It’s MW 3500.

3. The amino acid sequence of Glucagon

4. • It is secreted by the alpha cells of the islets of
Langerhans.
• Commercially glucagon produced now by
recombinant DNA technology.

5. Regulation of Secretion
 Glucagon is also derived by cleavage of larger peptide
prohormone.
 Glucagon secretion is regulated by dietary glucose, insulin,
amino acids, fatty acids, paracrine hormone & nervous
system.
 Amino acids stimulate both glucagon & insulin secretion

6. • The free fatty acids & ketones inhibits
glucagon secretion.
• Stimulation of sympathetic nerves or
administration of sympathomimetic amines
increases glucagon secretion.

7. Actions
Glucagon causes hyperglycemia mainly by enhancing
glycogenolysis & gluconeogenesis in liver.
In adipose tissue, it stimulate adenylyl cyclase & increase
lipolysis.
In the heart glucagon increases the force of contraction.

8. • Glucagon has relaxant effects on the gastrointestinal
tract & inhibit gastric acid production.
• It plays essential role in the development of diabetic
ketoacidosis.
• Glucagon is considered as hormone of fuel
mobilization.

9. Mechanism of action
Glucagon interacts with a glycoprotein GPCR through Gs &
activates adenylyl cyclase & increase cyclic AMP in liver, fat
cells, heart & other tissues.
Glucagon is inactive orally; that released from pancreas, is
broken down in liver, kidney, plasma & other tissues.

10. Therapeutic Uses
Hypoglycemia- Glucagon is used to treat severe
hypoglycemia. Dose- 0.5-1.0 mg i.v. or i.m.
GLUCAGON 1mg injection.

11. • Cardiogenic shock- Glucagon used to stimulate the
heart in ß adrenergic blocker treated patients.
• Glucagon is used to relax the intestinal tract to
facilitate radiographic examination of GIT.
★ Contraindication–
• Glucagon therapy is contraindicated in known
pheochromocytoma.

12. References
1. KD Tripathi, Essentials of MEDICAL
PHARMACOLOGY, 8th edition, 2019.
2. Laurence L. Brnton, John S. Lazo,
Goodmam & Gilman’s The Pharmacological
Basis of THERAPEUTICS, Eleventh edition.

13. Thank you for listening
me.