The Lizard Behind Ozempic

Predict

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?

Circle one. Yes / No

Why?

Watch

1. Ozempic exists because of a LIZARD!youtube.com/shorts/3CZu2rwL4NQ

Word of the day

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.

• A peninsula is land almost surrounded by water. Peninsula joins Latin paen-, “almost,” and insula, “island.”
• Pepsin, penicillin and aspirin end in the same chemistry ending -in.

Bonus word. Homeostasis (hoh-mee-oh-STAY-sis) means a living thing keeps its internal conditions steady while conditions outside change. The word joins Greek hómoios, “similar,” and stásis, “standing.” Hemostasis, the stopping of bleeding, ends with the same root.

Questions

1. After a meal, cells in your gut release GLP-1. GLP-1 boosts insulin release when blood sugar is high, and the enzyme DPP-4 in the blood breaks GLP-1 down within about 2 minutes. How do these steps work together as a feedback loop that keeps blood sugar in a steady range?

   Hint. Trace what happens as blood sugar rises after the meal and then falls. When does the insulin boost stop?

2. In 1993, a team that included John Eng tested exendin-4 on insulin-making cells from rats. Exendin-4 pushed labeled GLP-1 off the GLP-1 receptor. Exendin-4 also raised cAMP, a messenger molecule inside the cells, as GLP-1 does, and boosted insulin release when sugar was present. What do the three results show about how exendin-4 acts on insulin-making cells?

   Hint. A receptor is a protein that a hormone binds. What does it mean if exendin-4 can take GLP-1’s place on the receptor and then trigger the same response?

3. Gila monsters make their own GLP-1 in the pancreas and gut. In 1997, Chen and Drucker found that exendin-4 comes from a separate gene, used only in the lizard’s salivary glands. About 53% of exendin-4’s first 30 amino acids match GLP-1. Is exendin-4 the Gila monster’s own GLP-1? Use the gene evidence to back up your answer.

   Hint. Two proteins can look alike and still come from different genes. Which gene makes each protein, and where is each gene used?

4. Semaglutide, sold as Ozempic, shares 94% of its amino acid 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? And what did the lizard research add on the way to Ozempic?

   Hint. Compare the two percentages. Then compare the years. Exenatide, a lab-made copy of exendin-4, was approved in 2005, and Ozempic in 2017.

Claim, evidence, reasoning

Going further

1. GLP-1 and exendin-4 boost insulin release when sugar is high. Scientists study this boost with insulin-making cells from animal pancreases, kept alive in dishes of liquid with sugar added. Plan an investigation to test whether exendin-4 boosts insulin release only when sugar is high. Name what you change, what you measure, what you keep the same and how many times you repeat each test.

   Hint. You need dishes with low sugar and dishes with high sugar. Decide which dishes get exendin-4.

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