alkaline reaction for several days, although this self-digestion may be omitted. Then precipitating the albuminous bodies by means of alcohol or by boiling” [4].
Zülzer also tried to treat some patients with his extract (in other hospitals, since at his own he did not find suitable cases of diabetes). He presented the results on June 15, 1908 during a meeting on internal medicine in Berlin. He summarized the results as follows: “Intravenously administered this hormone of the pancreas was able to decrease glycosuria and acetonuria for some time” [5]. He did not supervise the patients correctly since they were in different hospitals and the data were not totally convincing. Nevertheless, the results of his research are already quoted in the first textbook on endocrinology, published in 1910 by the Viennese Prof. Arthur Biedl, one of the founding fathers of endocrinology [6].
In later years, Zülzer modified the production of his preparation without describing it more precisely. In contrast to Banting and Best, Zülzer assumed that the hormone was not a protein; he hoped that a prolonged incubation of the crushed pancreas would lead to a breakdown of proteins and therefore result in a better extract – an error! It is interesting that he sometimes did not practice this incubation. This may explain why only some of his extracts were effective and others not. Like Banting and Best, Zülzer used alcohol for extraction. However, in Toronto the chemist Collip achieved a much better degree of purity than Zülzer by doing the following: “He used acid alcohol as the initial extractive but raised the alcohol concentration to about 80%. By this means certain inert objectionable materials were removed. The inert materials were filtered and the insulin precipitated from the alcohol solution by raising the concentration of alcohol to approximately 92%” [7]. Zülzer certainly produced effective extracts, but also repeatedly ineffective samples. This explains the very different results of the experiments on animals and also on people with diabetes. The funding of the work was also difficult. The Schering Co., which had initially financed the investigations, then revoked this financial support. In 1908, Zülzer tried in vain to obtain a scholarship from the University of Berlin for the Zoological Research Institute in Naples. Many years before, Paul Langerhans had received such a scholarship, but Zülzer did not have a godfather named Rudolf Virchow. Zülzer had applied for the extraction of insulin from the insular organ of fish in Naples. If he had been granted these 500 marks, it may, in all probability, have helped him to develop a very effective insulin preparation.
Oskar Minkowski’s Team Missed the Nobel Prize
Zülzer decided to have his extract examined at the Department of Internal Medicine in Breslau where Oskar Minkowski had just been appointed to the chair of Internal Medicine after leaving Greifswald. Minkowski’s collaborator, Joseph Forschbach was asked to carry out the investigations and he began doing so in December 1909. Minkowski later regretted not having looked more closely at this work. Zülzer’s preparations were sent from Berlin to Breslau. Forschbach injected the extract intravenously in 3 experiments on two pancreatectomized dogs. In all three experiments glucosuria decreased immediately after the injection (from 8.2 to 1.3%, from 7.8 to 2.98%, and from 5.63 to 0.68% glucose in the urine) and increased later on. Blood glucose was never measured. Encouraged by these results, Forschbach also administered the extract to people with diabetes. In the first one, glucosuria remained the same after the injection – but the preparation was already 16 days old. The second patient was a 33-year-old man weighing 58 kg. Glucosuria decreased slightly. However, he observed an increase in body temperature, tachycardia, and nausea [8]. Although the experiments on dogs showed an astonishing effect, Forschbach judged the preparation unsuitable for treatment: “The patients showed an almost frightening prostration, the pulse was hunting, in both cases vomiting occurred” [6]. This devastating judgement of a famous working group was of course a terrible setback for Zülzer. In 1914, Forschbach wrote in his textbook: “The attempts to find an organotherapy by administering pancreatic extracts or stimulating the internal secretion of the gland, according to the assumption of a pancreatogenic nature of diabetes, failed. The practitioner must therefore refrain from using the pancreatic hormone prepared by Zülzer” [9]. This Forschbach study, not carried out carefully and badly summarized, was frequently quoted in later years. MacLeod mentioned Zülzer in his Noble Prize lecture: “In 1907 Zülzer published results which must be considered, in the light of what we now know, as really demonstrating the presence of the antidiabetic hormone in alcoholic extracts of pancreas. But unfortunately, even although several diabetic patients were benefited by administration of the extracts, the investigations were not sufficiently completed to convince others, and, apparently, Zülzer himself was discouraged in continuing them because of toxic reactions in the treated patients.” Banting also mentioned Zülzer in his Nobel Prize lecture: “In 1908, Zülzer tried alcoholic extracts on six cases of diabetes mellitus and obtained favorable results, one case of severe diabetes becoming sugar free. His extracts were then tried by Forschbach in Minkowski’s clinic with less favorable results, and the investigation was abandoned by this group of workers” (www.nobelprize.org/prizes/medicine). In the first publications on insulin, the team in Toronto did not quote Zülzer, only mentioning him after the patent issue.
Roche’s Board Members Missed a Big Deal
In 1910, Zülzer negotiated with the Hoechst Company, but they refused to cooperate. Zülzer had to continue working with his limited private means. In 1911, Hoffmann La Roche became interested in his work. With this support, Zülzer was able to set up a laboratory in the Hasenheide hospital and to collaborate with the chemist Dr. Camille Reuter (1886–1974), an employee of Roche working in the company’s laboratory in Grenzach, and pupil of Prof. Richard Martin Willstädter (who received the Nobel Prize for his work on chlorophyll in 1915 and had to emigrate to Switzerland in 1939). In 1914, Reuter continued to produce extracts in the Roche laboratories in Grenzach in Germany, located near Basel in Switzerland. Camille Reuter even processed over 100 kg of pancreata. In August 1914, these extracts very often led to severe cramps or death in experimental animals. The results of this research performed by Reuter in the Roche laboratories were not published. Nevertheless, following the discoveries in Toronto, Camille Reuter reported on this work in a scientific meeting in Luxembourg on January 13, 1924 [10]. Reuter reported that he had started to evaluate the effect of the extracts by measuring glycemia in dogs, it happened that glycemia dropped down to 0.017% in an animal. He even treated a patient with severe diabetes, stating that glycemia dropped and glucosuria disappeared [10].
Reuter, who was the head of the laboratories of Roche at the time, discussed the findings with his board. The board decided to abandon this research. The Hoffmann la Roche board members thought that the action of the intravenously injected extract was far too short and that nobody would ever consider injecting an antidiabetic agent multiple times per day for many years. They decided to focus on the development of oral agents to treat diabetes. Reuter filed the results of his work in the archives of Roche in November 1914, they were not available to the public. In 1924 he published the details of the research he had carried out in the Roche laboratories in 1914 [11]. Camille Reuter left Roche and returned to Luxembourg. He died in his home country Luxembourg in 1974.
If Zülzer had frequently measured the blood glucose concentration of his animals it would have been a direct path to the Nobel Prize – but he never did. Blood glucose measurements were still very complex in those days: a lot of blood was needed. Later, new methods required less blood and made
