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.
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