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The Lizard Behind Ozempic, High school

A Gila monster, a lizard with beaded black and orange scales, at Buenos Aires National Wildlife Refuge in Arizona

The Gila monster is a big orange and black lizard with a venomous bite. Its venom holds a molecule that works like a hormone your body makes after you eat.

Could a molecule from lizard venom lead to a medicine for people?

Ozempic exists because of a LIZARD!

The Gila monster is a big orange and black lizard with a venomous bite. A scientist found a molecule in its venom that works like a hormone your body makes after you eat, and the lizard molecule lasts for hours instead of minutes. That molecule led to exenatide, a new kind of medicine for high blood sugar, in 2005. Exenatide paved the way for medicines like Ozempic.

A digital thermostat on a wall, showing a temperature setting in Celsius
A peninsula is land almost surrounded by water. Peninsula joins Latin paen-, “almost,” and insula, “island.”

Your word of the day is

IN-suh-lin

insul-islandfrom Latin insula
-inan ending for names of chemicalsfrom New Latin -ina

A hormone made in the pancreas that helps the body’s cells take in sugar from the blood.

A dinner of brown rice, beans, squash, mango and milk

GLP-1 boosts insulin release when blood sugar is high, and DPP-4 breaks GLP-1 down within about 2 minutes.

How do GLP-1, insulin and DPP-4 work together as a feedback loop that keeps blood sugar steady?

Video of gloved hands holding a blood glucose meter that reads 121 mg/dL

In 1993, exendin-4 pushed labeled GLP-1 off the GLP-1 receptor of rat insulin-making cells, raised cAMP and boosted insulin release.

What do the 1993 rat cell results show about how exendin-4 acts on insulin-making cells?

A reticulate Gila monster, with a net-like pattern of black and orange scales

Gila monsters make their own GLP-1 in the pancreas and gut, and exendin-4 comes from a separate gene used only in the salivary glands.

Is exendin-4 the Gila monster’s own GLP-1?

A pharmacist in gloves, seen from behind, sorting medicine on pharmacy shelves

Semaglutide, sold as Ozempic, shares 94% of its sequence with human GLP-1. Exendin-4 shares about 53% of its first 30 amino acids with GLP-1.

Why do scientists say Ozempic didn’t come from a lizard?

A Gila monster near Patagonia Lake in southern Arizona

Exenatide, a lab-made copy of exendin-4, was approved in 2005, and Ozempic in 2017.

What did the Gila monster research add on the way to Ozempic?

A Gila monster among dry leaves in the Las Cienegas National Conservation Area in Arizona

Claim, evidence, reasoning

GLP-1 lasts about 2 minutes and exenatide lasts 2.4 hours. DPP-4 cuts quickly when the second building block is A or P. GLP-1 has A there, and exendin-4 has G.

Which claim best explains why exendin-4 lasts so much longer than GLP-1?

A scientist in a lab coat looking through a microscope

Claim, evidence, reasoning

Which evidence backs the claim that DPP-4 can barely cut exendin-4?

A Gila monster crossing a dirt road in the Las Cienegas National Conservation Area in Arizona

Claim, evidence, reasoning

Which reasoning connects the second building block to how long exendin-4 lasts?

Gloved hands preparing plates of cells grown in a lab for a centrifuge

Scientists study insulin release with insulin-making cells from animal pancreases, kept alive in dishes of liquid with sugar added.

To test whether exendin-4 boosts insulin release only when sugar is high, which dish setup tests both factors?

Video of a pipette dropping liquid into petri dishes in a lab

In a dish test of exendin-4 and insulin release, what should you measure?

A mouse pancreatic islet under a fluorescence microscope, with insulin stained red and glucagon stained green

Which plan keeps a dish test of exendin-4 and insulin release fair?

A Gila monster near Patagonia Lake in southern Arizona, its black and orange beaded skin in view

Exendin-4 lasts for hours, and GLP-1 lasts about 2 minutes. GLP-1’s second building block is alanine, and exendin-4’s is glycine.

How does one building block explain why exendin-4 lasts hours and GLP-1 lasts minutes?

A Gila monster walking over gravel toward the camera in Saguaro National Park

How does a short-lived GLP-1 help keep blood sugar steady?

A pig drinking water in a pen

Lesson complete

Today’s word

insulin

IN-suh-lin

A hormone made by clusters of cells in the pancreas called the islets of Langerhans. Insulin helps cells take in sugar from the blood.

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Up nextadaptationThe Evolution of Skin Color
Sources
  1. John Eng, an endocrinologist at the Bronx VA Medical Center, with W. A. Kleinman, L. Singh, G. Singh and Jean-Pierre Raufman, Journal of Biological Chemistry, 1992
  2. R. Göke, H. C. Fehmann, T. Linn, H. Schmidt, M. Krause, John Eng and B. Göke, Journal of Biological Chemistry, 1993
  3. Y. E. Chen and D. J. Drucker, Journal of Biological Chemistry, 1997
  4. C. M. Christel and D. F. DeNardo, Comparative Biochemistry and Physiology A, 2006
  5. R. Mentlein, B. Gallwitz and W. E. Schmidt, European Journal of Biochemistry, 1993
  6. C. F. Deacon, L. B. Knudsen, K. Madsen, F. C. Wiberg, O. Jacobsen and J. J. Holst, University of Copenhagen and Novo Nordisk, Diabetologia, 1998
  7. Reviews by Drucker, Habener and Holst, and by T. D. Müller and colleagues, Journal of Clinical Investigation, 2017 and Molecular Metabolism, 2019
  8. US Food and Drug Administration prescribing labels, Byetta label and Ozempic label
  9. Golden Goose Award, John Eng awardee page and 2013 announcement, for Eng’s work at the Bronx VA, the 1992 discovery and the path to Byetta
  10. Jake Currie, “How the Gila Monster Gave the World Ozempic,” Nautilus, 2026, for Eng’s title as an endocrinologist
  11. Smithsonian’s National Zoo, Gila monster
  12. UniProt P01275, the human proglucagon sequence, for GLP-1’s first five amino acids
  13. Vision and Change core concepts and competencies, as summarized in Brownell and others, CBE Life Sciences Education, 2014
  14. Word origins from Dictionary.com: insulin, -in, insula, insular, homeostasis, homeo-, stasis, peninsula, hemostasis, hemo-, thermostat, insulate, homeomorphism, Gila monster
  15. Spanish, French and Italian spellings from Wiktionary: insula, insulin