Insulin, a hormone that regulates blood sugar, has been a life-saving treatment for individuals with diabetes for over a century. For many decades, the primary source of this medication was animal pancreases, particularly from pigs. This reliance on pig insulin was a significant chapter in diabetes management, providing a lifeline before advanced biotechnological methods.
The Rise of Animal Insulin
The discovery of insulin in the early 20th century marked a revolutionary moment in medicine. In 1921, Frederick Banting and Charles Best successfully isolated an extract from the pancreas that could lower blood sugar. Their initial experiments involved removing the pancreas from dogs, which led to symptoms resembling diabetes, and observing the effects of pancreatic extracts on these animals.
The team refined their extraction methods, ultimately producing insulin pure enough for human trials in 1922. Initial results in diabetic patients transformed a previously fatal diagnosis into a manageable condition. Due to anatomical similarities and availability from slaughterhouses, pigs and cattle quickly became primary sources for large-scale insulin production. This widespread availability profoundly impacted diabetes care, increasing life expectancy for diabetic patients.
Understanding Pig Insulin’s Structure and Effects
Pig insulin shares a close structural resemblance to human insulin, making it effective in regulating blood glucose in humans. The key difference lies in a single amino acid at position B30 of the insulin B-chain. This minor variation could have implications for some patients.
The structural difference meant that pig insulin, being a foreign protein, could sometimes trigger an immune response in the human body. This response might manifest as allergic reactions, from mild skin irritations to more severe systemic reactions. The body could also produce antibodies against pig insulin, binding to it and affecting its absorption and effectiveness. This could necessitate higher insulin doses or lead to inconsistent blood sugar control for long-term users.
The Shift to Synthetic Human Insulin
The advent of recombinant DNA technology in the late 20th century fundamentally changed insulin production. This technology allowed scientists to engineer microorganisms, such as E. coli or yeast, to produce human insulin structurally identical to that made in the human pancreas. This process involves isolating the human gene for insulin production and inserting it into the genetic material of these microorganisms, turning them into insulin producers.
Synthetic human insulin offered several advantages over animal-derived versions. Its identical structure minimized the risk of immunological reactions, common with animal insulins. This genetic engineering also ensured a consistent and abundant supply of insulin, addressing concerns about reliance on animal sources. The higher purity of biosynthetic insulin, free from animal proteins and impurities, improved patient safety and treatment predictability. These advancements led to the gradual phasing out of animal insulins, with synthetic human insulin becoming the standard of care for diabetes management.