Not All Heroes Wear Capes, Some Come In A Vial: The History of Insulin

Introduction

In January 1922, a 13-year-old boy named Leonard Thompson received the world’s first insulin injection.  After a month spent in Toronto General Hospital, his condition had not improved, and he weighed just 65 pounds.  Once regular insulin injections were administered, the young boy’s blood sugars declined, allowing his body to absorb the glucose from his bloodstream.  He rapidly gained weight and strength, succumbing only to a severe case of pneumonia at the age of 27. 

Types of Diabetes

Type 1 diabetes is a condition in which the body is unable to produce insulin due to an autoimmune attack on the islet cells in the pancreas.  It is typically diagnosed in childhood, and thus is colloquially coined as “juvenile diabetes”.  There is no cure, and the treatment is insulin management.

Type 2 diabetes causes elevated blood sugars due to either a decrease in insulin production or faulty insulin.  It is oftentimes preventable through regular diet and exercise, although this is not always the case.

There are many other less common types of diabetes, such as:

• Gestational diabetes 

• Maturity onset diabetes of the young (MODY)

• Neonatal diabetes

• Latent autoimmune diabetes in adults (LADA)

• Type 3c diabetes

• Steroid-induced diabetes

• Cystic fibrosis diabetes

• Type 5 diabetes

Old Mechanism

Until the 1980s, insulin was extracted from the pancreases of pigs and cattle.  Because porcine and bovine insulin is nearly identical to human insulin, it was effective in lowering blood sugars in diabetic patients.  However, many patients experienced allergic reactions as the purification process was imperfect.  Additionally,  more than two tons of pig pancreases was required to produce a mere eight ounces of insulin, so it wasn’t a particularly humane or efficient method of manufacturing the lifesaving substance.  

New Mechanism

Today, insulin is manufactured via bacterial plasmids.  Plasmids are circular molecules of DNA  found inside most bacteria and some eukaryotic cells.  Scientists remove a portion of the plasmid, build the gene for human insulin in the laboratory, and then insert the gene into the plasmid.  These “recombinant” bacteria are then inserted into fermentation tanks, where they use the gene to create human insulin.  Scientists then gather the insulin from the bacteria, purify it, and sell it in vials.

Conclusion

Prior to Leonard Thompson’s case, diabetes was considered a death sentence, and patients did not survive longer than a few weeks to months.  Today, diabetes is still the 9th leading cause of death worldwide, but the growing prevalence of medical innovation has greatly improved quality of life for those living with diabetes. For more information about diabetes and related conditions, check out the American Diabetes Association website (diabetes.org).

Resources

Admin. (n.d.). Types of diabetes. Diabetes UK. https://www.diabetes.org.uk/about-diabetes/types-of-diabetes

Excellence, Um. D. C. of. (2025, July 2). Leonard Thompson received first human insulin injection to treat diabetes: January 1922. UMass Chan Medical School. https://www.umassmed.edu/dcoe/diabetes-education/patient-resources/first-insulin-injection/

The history of a wonderful thing we call insulin. The History of a Wonderful Thing We Call Insulin | American Diabetes Association. (n.d.). https://diabetes.org/blog/history-wonderful-thing-we-call-insulin

Insulin development and commercialization. American Chemical Society. (n.d.). https://www.acs.org/education/whatischemistry/landmarks/insulin.html

Mudaliar, S. (2023, February 21). The evolution of diabetes treatment through the ages: From starvation diets to insulin, incretins, SGLT2-inhibitors and beyond. Journal of the Indian Institute of Science. https://pmc.ncbi.nlm.nih.gov/articles/PMC9942084/

National Institutes of Health. (n.d.). How did they make insulin from recombinant DNA?. U.S. National Library of Medicine. https://www.nlm.nih.gov/exhibition/fromdnatobeer/exhibition-interactive/recombinant-DNA/recombinant-dna-technology-alternative.html

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