Animal Experimentation - Frequently Asked Questions: Wasn't it through lab animals that scientists discovered diabetes and developed insulin?
An Animal Rights Article from


AFMA Americans for Medical Advancement
March 2006

 Wasn't it through lab animals that scientists discovered diabetes and developed insulin?

Pro-animal experiment contingencies always site the development of insulin as support for continued animal testing. They assert, with justification, that without insulin harvested from slaughterhouses many diabetics would have lost their lives. Whereas it is true that animals have figured largely in the history of diabetic research and therapy, their use has not been necessary and furthermore has not always advanced science.

Diabetes is a very serious disease, even today affecting ten to fourteen million Americans. It is a leading cause of blindness, amputation, kidney failure and premature death. Although the clinical signs of human diabetes have been known since the first century AD, not until the late eighteenth century did physicians associate the disease with characteristic changes in the pancreas seen at autopsy. As this was difficult to reproduce in animals, many scientists disputed the role of the pancreas in the disease.

Nearly a century later, in 1869, scientists identified insulin-producing pancreatic cells that malfunction in diabetic patients. Other human pancreatic conditions, such as pancreatic cancer and pancreatitis (inflammation of the pancreas) were seen to produce diabetic symptoms, reinforcing the disease's link with the pancreas.

Animal experimenters continued to interrupt the nicely progressing course of knowledge regarding the pancreas and diabetes. When they removed pancreases from dogs, cats, and pigs, sure enough, the animals did become diabetic. However, the animals' symptoms led to conjecture that diabetes was a liver disease, linking sugar transport to the liver and glycogen. These animal studies threw diabetes research off track for many years.

In 1882, a physician named Dr. Marie noted the association between acromegaly, a pituitary disorder, and sugar in the urine, thus connecting sugar metabolism and the pituitary gland. Another doctor, Atkinson, published data in 1938 that revealed 32.8 per cent of all acromegalic patients suffered from diabetes. Bouchardat published similar findings in 1908. For some reason, the scientist who reproduced this in dogs, Bernardo Houssay, ended up winning the Nobel Prize in 1947. Obviously, it is hardly fair to say dogs were responsible for his kudos, since knowledge predated Houssay's experiments and any number of human-based methods would have produced the same findings.

In the early 1920s two scientists, John Macleod and Frederick Banting, isolated insulin by extracting it from a dog. For this they received a Nobel Prize. Macleod admitted that their contribution was not the discovery of insulin, but rather reproducing in the dog lab what had already been demonstrated in man. They were not obliged to extract insulin from dogs, because certainly there was ample tissue from humans. They merely did so because it was convenient. In that same year Banting and another experimenter, named Best, gave dog insulin to a human patient with disastrous results. Note what scientists said about the dog experiments in 1922,

The production of insulin originated in a wrongly conceived, wrongly conducted, and wrongly interpreted series of experiments.

Banting, Best and other scientists modified the process using in vitro techniques and later mass-produced insulin from pig and cow pancreases collected at slaughterhouses.

In coming years scientists continued to refine the animal-derived substance. Though it is true that beef and pork insulin saved lives, it also created an allergic reaction in some patients. Beef insulin has three amino acids that differ from human amino acids while pork insulin has only one. Whereas this sounds negligible, it takes very little amino acid discrepancy to undermine health. (Only one deviant amino acid is enough to produce certain life threatening diseases, such as cystic fibrosis or sickle cell anemia.) Injecting animal-derived insulin also presented the sizable danger of transmitting viruses that cross from one species to another. Had researchers then recognized these potentialities as well as the gulf of differences between humans and farm animals, scientists would have hastened to develop human insulin more quickly.

The ability to treat patients suffering from diabetes without giving them insulin injections was discovered by chance on humans. Today, the administration of oral anti-hyperglycemics, which arose from serendipity and self-experimentation, eliminates the need for insulin injections in many patients.

Diabetes is still stunningly enigmatic, in large part due to our continued reliance on the animal model. Most clinicians believe that strict glucose control though insulin injections offers advantages over a less regimented treatment plan. However, insulin is a treatment not a cure for diabetes. The exact biochemical process through which insulin regulates blood sugar is not yet known.

Go on to: Animal Experimentation - Frequently Asked Questions: Would drugs be safe for us without being tested first on animals?

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