maddeningly imprecise because of the The History of difficulty of measuring the physiological effect of various interventions. The secret

MICHAEL BUSS, PHD of the could not be uncovered without better tools. The development of methods that permitted rapid serial readings of THE PREHISTORY OF INSULIN — many or D.A. Scott in the U.S., were, in blood glucose levels was a precondition Insulin received its name before it was fact, administering active insulin. But it for the eventual breakthrough. By 1919, discovered. In 1889 in , Oskar was impossible to present clear evidence an advanced researcher, Israel Kleiner, Minkowski and Joseph von Mering ob- of benign hormonal action because of so working at the Rockefeller Institute, was served that total pancreatectomy in ex- many toxic contaminants in their prepa- able to show that intravenous injections perimental animals leads to the develop- rations. Beginning in 1906, for example, of aqueous solutions of ground fresh ment of severe mellitus, and Zuelzer occasionally was able to reduce pancreas had a regular hypoglycemic ef- began the speculation that a mysterious glycosuria and acidosis in human dia- fect. Only a pattern of slight toxic effects substance produced by the pancreas is betic individuals; but the results were of his extracts prevented him from at- responsible for metabolic control (1,2). accompanied by such severe, life-threat- tempting the administration to human Supporting evidence for the hypothesis ening reactions that workers in diabetic individuals, which, if successful, gradually mounted: It included observa- Minkowski's laboratory dismissed his would be judged real proof of discovery. tions of the relationship between diabe- work as inconclusive and dangerous (4). Unfortunately for Kleiner, he left the tes and damage to the pancreatic cellular Even so, there was so much im- Rockefeller Institute that year for a uni- system known as the islets of Langer- pressionistic evidence supporting the ex- versity that did not have the resources to hans, as well as the discovery and eluci- istence of a pancreatic internal secretion, support major animal research and he dation of the physiology of internal or emanating from the islet cells, that, in abandoned the work. Other investiga- endocrine secretions. By the first decade 1909, a Belgian investigator, J. de Meyer, tors, such as Paulesco in Romania, were of the 20th century it was widely hypoth- proposed it be named "insuline" (5). In making very slow progress because of esized that an "internal secretion" of the 1916, E.A. Schafer in Britain indepen- inadequate funding and hopelessly prim- pancreas controls carbohydrate metabo- dently suggested the same name (6). itive experimental techniques (7,3). lism (3). Much truth is in the notion, again clari- But no one could demonstrate fied by hindsight, that insulin was sitting that the internal secretion actually ex- there waiting to be isolated or "discov- BANTING'S RESEARCH— In 1920, isted. Minkowski himself was the first of ered." It almost certainly would have Frederick Grant Banting was a 22-yr-old innumerable researchers and physicians been found during the second decade of physician and surgeon attempting to who administered pancreas solutions, the twentieth century, but the work of launch a general practice in the small orally and by injection, to diabetic ani- Central European researchers, such as Canadian city of London, Ontario. With mal and human subjects in the hope of Zuelzer and the Romanian physiologist, time on his hands, he accepted a dem- replacing the missing substance. Results N.C. Paulesco, was utterly disrupted by onstratorship in surgery and anatomy at were decidedly mixed and inconclusive. World War I. London's Western University. On Mon- Experiments in which extracts of the On the other hand, careful stu- day, 31 October, he had to talk to phys- pancreas appeared to reduce glycosuria dents of carbohydrate metabolism knew iology students about carbohydrate me- often were unrepeatable or marred by that there might be other explanations tabolism, a subject with which he was strange patterns of fever and other reac- (relating to the nervous system or other not particularly familiar. Late Sunday tions. With the wisdom of hindsight, we pancreatic mechanisms) for the relation- night, as part of his preparation, he read now know that many of these experi- ship between pancreatic failure and dia- the leading article in the November issue menters, such as Georg Zuelzer in Ger- betes. And experimentation had been of Surgery, Gynecology and Obstetrics, a discussion of "The Relation of the Islets of Langerhans to Diabetes with Special Reference to Cases of Pancreatic Lithia- From the Department of History, University of Toronto, Toronto, Canada. sis," by Moses Barron (8). Barron's unre- Address correspondence and reprint requests to Michael Bliss, PhD, Department of History, markable report stimulated a train of University of Toronto, Canada, M5S 1A1. thought in Banting's mind that caused him, sometime after midnight, to jot

DIABETES CARE, VOLUME 16, SUPPLEMENT 3, DECEMBER 1993 Bliss

down this idea: "Diabetus Ligate pancre- glycemic effects. When Macleod returned reductions of glycemia and glycosuria, had atic ducts of dog. Keep dogs alive till in September, he urged Banting and Best no effect on ketoacidosis or the patient's acini degenerate leaving islets. Try to iso- to repeat and amplify their experiments. subjective presentation, and resulted in the late the internal secretion of these to re- He discouraged Banting from venturing formation of a sterile abscess. "These re- lieve glycosurea" (9). down the grafting road and, after some sults were not as encouraging as those ob- Banting enjoyed dabbling in re- friction with the young doctor, supplied tained by Zuelzer in 1908," Banting later search and was unhappy in his fledgling more space and dogs. wrote. Treatment was immediately discon- practice. He returned to his alma mater, By December, Banting and Best tinued (11). the University of Toronto, and ap- had accumulated further evidence that On January 23, a new series of proached J.J.R. Macleod, professor of their extract often reduced the blood glu- injections began. Thompson responded physiology, with a proposal to engage in cose of diabetic dogs. After experiments immediately. His glycosuria almost dis- summer research to test his "Diabetus" with fetal calf pancreas and then with appeared, his ketonuria did disappear. idea. Macleod, a noted expert in carbo- fresh beef pancreas, Banting found he His blood glucose dropped to normal. hydrate metabolism, doubted that a nov- could dispense with the cumbersome He was brighter and stronger. For the ice could succeed where masters had duct-ligation/atrophication procedures first time in history there was clear, un- failed. However, he may have seen some (though he never quite realized that in ambiguous evidence that scientists were value in Banting's hypothesis that the doing so he had disproven his original able to replace the function impaired in internal secretion was somehow being hypothesis of an antagonism between the diabetes. This was the demonstration of nullified in pancreatic extracts by the ac- pancreatic secretions). Because of Best's the isolation of the internal secretion of tion of the externally secreted digestive inexperience, Macleod and Banting de- the pancreas that the world had awaited ferments. By ligating the pancreatic cided to addJ.B. Collip to the research for 30 years. ducts, Banting hoped to induce atrophi- team. Collip, a biochemist from the Uni- It wasJ.B. Collip, the biochemist, cation of the acinar cells and eliminate versity of Alberta, was visiting Toronto to who had produced the successful ex- the external secretion, thus liberating the work with Macleod and had expressed tract. He had developed a method of internal secretion. Banting's training as a an interest in the pancreas work. extraction that involved changing the surgeon would serve him well in such The first presentation of the To- concentrations of slightly acidic alcohol research; it also predisposed him to an ronto research, read at the New Haven solutions of chilled beef pancreas (it is interest in grafting experiments as the meeting of the American Physiological not clear which members of the research second stage in his work. In an age be- Association on 30 December 1921, was team first suggested using acid alcohol) fore the rejection phenomenon was un- not well received. In their inexperience until he was able to precipitate out the derstood, several experts had suggested and haste, Banting and Best had been active principle relatively free from toxic pancreatic grafts or transplants as a sloppy and muddled. Their lack of data contaminants. It was a major improve- promising direction in the search for the on the side-effects of their extracts, for ment on Banting and Best's methods, the elusive secretion. With surplus facilities example (which were almost certainly single most important step forward in at hand in his very well-equipped labo- pyrogenic, as others had been), meant the discovery process (12,13). ratory, Macleod agreed to give Banting that it was difficult to convince anyone Unfortunately, the triumph was space, dogs, and a student assistant for a that their findings were better than those marred by bitter personal rivalries; summer "fling" at the problem. One of of Kleiner and others. The team's most Banting and Best believed that Collip and Macleod's summer students, Charles recent experiments, notably evidence Macleod were conspiring to take over Best, won a coin toss to see who would compiled by Collip on the extract's ap- control of the work and credit for its start work with Banting (3). parent restoration of glycogen mobiliza- success. Physical and verbal confronta- Banting began his research, as- tion in the liver and its ability to clear tions often disrupted the research. Face- sisted by Best, on 17 May 1921. Macleod ketones, may have seemed more prom- saving agreements, such as a decision to was both the formal supervisor and an ising (3,10). publish alphabetically, barely camou- active adviser before leaving the city in flaged intense personal dislikes. Bitter mid-June. The casualty rate among THE DISCOVERY OF INSULIN — controversy about credit for the discov- Banting's dogs was high, some depancre- On 11 January 1922, clinicians at Toronto ery of insulin scarred Toronto's great atized, others duct-ligated. At the end of General Hospital injected a 14-year-old, achievement until the last of the re- July, he and Best began intravenous in- severely diabetic boy, Leonard Thompson, searchers, Best, died in 1978. Banting jections into depancreatized animals of with 15 ml of pancreatic extract made by and Best were particularly confused and saline extracts of chilled atrophied pan- Banting and Best. This clinical test was a self-serving in their refusal to recognize creas. They observed a pattern of hypo- failure. The injection caused only slight their collaborators' contributions to the

DIABETES CARE, VOLUME 16, SUPPLEMENT 3, DECEMBER 1993 The history of insulin

work, in refusing to recognize as Llewe- simultaneously with and independently THE MULTIPLICATION OF lyn Barker put it, that "in insulin there is of a research team at Washington Uni- — At first, it was hoped glory enough for all" (3). versity in St. Louis, discovered a method that insulin could be delivered orally, The glory came almost immedi- of producing large quantities of much and/or that a more fundamental hypo- ately. On 3 May, 1922, Macleod deliv- purer insulin through isoelectric precip- glycemic substance, perhaps contained ered a complete summary of the Toronto itation. In early 1923, Clowes boasted of in plants, remained to be isolated. For work at the Washington meeting of the Lilly's capacity to produce enough insu- almost a decade, there was dispute over Association of American Physicians. By lin "to supply the entire needs of the insulin's chemical composition. Manu- now it had been decided to name the civilized world." In point of fact, the To- facturers gradually improved the purity active principle "insulin." Macleod sug- ronto group had granted Lilly only a one- of the product; and, in 1926, JJ. Abel at gested the Latin root for islands without year exclusive license on insulin produc- Johns Hopkins was able to crystallize in- knowing of Meyer's and Schaeffer's ear- tion for the United States and Latin sulin. In the next few years it was finally lier proposals. The audience agreed that America. To solidify control of the dis- accepted that the is a protein. the Toronto team had made one of the covery, the researchers had assigned pat- The study of insulin would have a great great breakthroughs in modern medicine ents on their methods to the University impact on protein chemistry over several and gave them a standing ovation (14). decades (15). In the meantime, manufac- Eighteen months later, in one of the fast- of Toronto, which licensed manufactur- turers strove to develop insulin com- est recognitions of a medical discovery in ers in other countries—including its own pounds that would most effectively meet its history, the Nobel Committee of the Connaught Laboratories in Canada—as the requirements of users for easy ad- Caroline Institute awarded the 1923 No- well as competitors in the United States. ministration and closer matching with bel Prize in physiology or medicine to One of the first Europeans to visit physiological need. Banting and Macleod. Banting divided Toronto to learn about insulin was Au- his prize money equally with Best; Ma- gust Krogh, a Danish Nobel laureate, The first Toronto patients re- cleod split his with Collip. The Nobel who we now know was eager to obtain ceived one injection a day of an ex- Committee was probably mistaken in not insulin to treat his wife's diabetes. Aided tremely impure insulin. As "regular" bo- having named Collip as a co-recipient of by a brilliant chemist, H.C. Hagedorn, vine and porcine insulin was increasingly the prize. Krogh began insulin production in purified in the early years of manufac- Copenhagen early in 1923 at their Nor- ture, patients complained of the incon- THE DEVELOPMENT OF INSULIN - disk Insulin Laboratory. All of the pio- venience of having to take several injec- The Toronto team was attempting to ex- neering manufacturers faced immediate, tions a day. A search began to prolong tract an unknown substance from the immense problems involving standard- the action of insulin by combining it pancreas with what we would now con- ization of the product, dosage, diet, phy- with other substances. In the mid-1930s, sider primitive equipment. It was unable sician and patient education. On the Hagedorn in Denmark discovered that to produce insulin in anything but labo- other hand, there were, as yet, no gov- basic proteins, notably protamine, when ratory batches, and even these were often ernment regulatory hurdles to overcome. added to insulin could prolong its action. contaminated, weak, or completely inef- It is a testimony to the idealism and ef- In Toronto, Scott and Fisher simulta- fective. After many frustrating failures in ficiency of both the University of To- neously learned that zinc also had a lengthening effect. These discoveries the spring of 1922, it was decided to ronto group and the leading manufactur- paved the way for a gradual multiplica- undertake a joint venture with Eli Lilly ers that, by the end of 1923, insulin was tion of insulin products in the late 1930s and Company of Indiana, a well-estab- being used commercially and safely to and 1940s. Protamine-zinc insulin (PZI) lished, ethical drug company whose re- treat people with diabetes in most West- search director, G.H.A. Clowes, had ex- jostled onto the marketplace with prota- ern countries. The two major producers, pressed persistent interest in the work. A mine- or isophane-insulin (NPH), and Lilly in the United States and the Danes formal agreement was signed on 30 May, soon combinations of the long-lasting in Europe (Novo Company developed as 1922, and Best and Collip went to Indi- and regular insulins were available. In an early breakaway group from Nor- anapolis to share all the formulas. By the the mid-1950s, Novo pioneered the in- disk), used their head start in insulin end of June, Lilly was producing potent troduction of the lente insulins, which knowledge to begin to build a global preparations of porcine insulin, which contained zinc but not protamine. Innu- dominance in insulin manufacture that were shipped to Toronto for testing. merable mixtures of quick-acting, inter- remains today, and so, gloriously, do The most important break- mediate, and long-acting insulin were many of the patients first treated with through in insulin development was now possible. Many patients now took insulin in the early 1920s. made that autumn when Lilly chemists, insulin only once a day, but many others

DIABETES CARE, VOLUME 16, SUPPLEMENT 3, DECEMBER 1993 Bliss

seemed to do better on multiple doses explosion in our knowledge of DNA and gans. London, Nelson, 1916 (16). the processes of life itself. Within an- 7. Kleiner IS: The action of intravenous in- In the 1970s, yet another gener- other twenty years, what had once jections of pancreas emulsions in exper- ation of animal insulins was introduced seemed a wild science-fiction dream, the imental diabetes. J Bio! Chem 40:153-70, as a result of new processes aimed at idea of manipulating genes to create life 1919 eliminating proinsulin and other immu- forms in the laboratory, was now a prac- 8. Barron M: The relation of the islets of nogenic peptides. These "monocompo- tical possibility. The great scientific rev- Langerhans to diabetes with special ref- nent" insulins took the preparation of olution of our time—the advent of mo- erence to cases of pancreatic lithiasis. pure insulin from animal lecular biology—made it possible to Surg Gyn Obst 31:437-48, 1920 about as far as it could go. Throughout conceive of genetic engineering tech- 9. Banting Notebook: 1920-21. Fisher Rare all these years, it was remarkable that the niques that could lead to the biosynthesis Book Library, University of Toronto, To- ronto, Canada animal pancreas supply had never been a of real human insulin. 10. Banting FG, Best CH: The internal secre- problem in the developed countries. The era of animal insulins, as tion of the pancreas. J Ijab Clin Med However, some countries had occasional they had become life-saving, creatively 7:256-71, 1922 supply shortages during World War II. compounded, and beautifully purified, 11. Banting FG: The history of insulin. Ed The more common reasons for insulin drifted toward its end. Med] 9:1-18, 1929 not being available to people with diabe- 12. Banting FG, Best CH, Collip JB, Camp- tes, one suspects, were disorganized bell WR, Fletcher A A: Pancreatic extracts References manufacture in Third World and com- in the treatment of diabetes mellitus. Pre- munist countries, and missed diagnosis 1. Mering J Von, Minkowski O: Diabetes liminary Report. Can Med Assoc J Xll: by physicians everywhere. mellitus nach pankreasextirpation. Arch 141-46, 1922 Exp Paihol Pharmacol (Leipzig) 26:371- 13. Collip JB: The original method as used 87, 1890 for the isolation of insulin in semipure TOWARD A NEW ERA— Insulin 2. Zeller S, Bliss M, Minkowski O: Dictio- form for the treatment of the first clinical was given to the world as a result of nary of Scientific Biography. Suppl. 2, New cases. J Biol Chem LV:Xl-XlI, 1923 messy, confused, experimentation on liv- York, Scribner's, 1990, p. 626-33 14. Banting FG, Best CH, Collip JB, Camp- ing subjects. It was the mysterious, mag- 3. Bliss M: The Discovery of Insulin. Toronto, bell WR, Fletcher AA, MacleodJJR, No- ical secretion of the pancreas that re- McClelland and Stewart, 1982; Chicago, ble EC: The effect produced on diabetes searchers finally learned how to extract University of Chicago Press, 1983 by extracts of pancreas. Trans Assoc Am from animal pancreas—removed at the 4. Mellinghoff KH: Georg Ludwig Zuelzers Physicians XXXVlI:337-47, 1922 abattoir immediately after slaughter—in Beitrag zur Insulinforschung. Dusseldorf, 15. Mumaghan JH, Talalay P: John Jacob forms suitable for administration to hu- 1971 Abel and the crystallization of insulin. mans. 5. De Meyer J: Contribution a l'etude de la Persp Biol Med 10:334-81, 1967 By the late 1950s, chemists un- pathogenie du diabete pancreatique. 16. Sonksen PH: The evolution of insulin derstood the exact structure of the insu- Arch Int de Physiologie 121-80, 1909 treatment. Clin Endocrinol Metab 6:481- lin molecule in the context of a dazzling 6. Sharpey-Schafer EA: The Endocrine Or- 97, 1977

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