LEONID V. SOBOLEV - The History of Insulin Discovery
The History of Insulin Discovery
Historical and biographical paper on Leonid Vasilyevich Sobolev (L.V. Sobolev, 1876-1919), an outstanding Russian pathologist who established in his Ph.D. thesis (1901, Emperor’s Military Medical Academy, St. Petersburg) that the islets of Langerhans produce some “X factor” which was called insulin later. The results of Sobolev’s work as well as scanty information about his life and fate, which Russian specialists managed to find in 1950-2014, are presented in the paper. There are three hypotheses as to why Sobolev did not go on with his research, becoming the first one in the world to get insulin and use it for treatment (P. Trendelenburg’s, L. Salyamon’s and the author’s hypotheses). Lack of references to the results obtained by the Russian scientist in Banting’s and Best’s papers is discussed in the end, and the author comes to the conclusion that the Canadians probably did not know about Sobolev’s papers. (5 photos, 13 references)
Keywords: history of medicine, diabetes mellitus, islets of Langerhans, discovery of insulin, L.V. Sobolev
Leonid V. Sobolev was undoubtedly a genius. But like some gifted people with God given talent he was a modest and reserved man; it is possible that the reason of his sullenness was his falling ill when he was young. We do not know much about Leonid Sobolev – he has nearly fallen out of the constellation of great Russian scientists, there are no books written about him, there is very little information on him on the Web and one can count the authors who wrote about him on one hand only. He made a great discovery – he proved experimentally that the islets of Langerhans in the pancreas are exactly the ones which produce some hormone, “X factor” regulating blood glucose, which will be called insulin in later years. His scientific activities were associated with the St. Petersburg Military Medical Academy (MMA): he graduated from this educational establishment with flying colours in 1897 and was offered to stay as an adjunct professor at the pathological anatomy department, he presented his Ph.D. thesis in 1901 and in 1904 he was awarded the title of anatomist and after that the title of privatdocent at the same department. He taught students at the Academy till 1912 and it seems that he did not try to get some practical profit from his discovery – for example, create insulin much earlier than Frederick Banting and Charles Best did it. He was suffering from incurable disease of multiple sclerosis and retired in 1912 having no more strength to perform his obligations. Sobolev died in 1919, in the year of ruin and hunger in Petrograd, in the nervous diseases clinic of the MMA when he was forty-three. I have not managed to find out the exact dates of either his birth or his death in any historical sources. There is practically no information about him in the MMA archives, only some photos. Only few people wrote about him in the following years. The author of most papers of 1926-1950 is Professor D.M. Rossiysky (1887-1955) thanks to whom Sobolev’s thesis was reprinted in 1950 . Rossiysky also wrote a preface to it  in which he described the importance of Sobolev’s work, named the years of his birth and death, 1876-1919 (without either days or months) but there is practically nothing about the outstanding scientist’s private life and fate. There is some scanty information (one page) about him in  and in Professor V.G. Baranov’s (1900-1988) and Professor S.G. Genes’s (1898-1992) papers published in the «Клиническая медицина» (Clinical Medicine) in 1949. Professor L.S. Salyamon (1917-2009) reviews the history of “nearly discovered” insulin by Sobolev as an example of a great but not called for achievement of the Russian science . A recent paper by L.A. Sorokina  does not add anything new when compared with D.M. Rossiysky’s preface . In another article, also one of the latest – by G.A. Melnichenko with co-authors  – exact dates of Sobolev’s birth and death are provided: February 27, 1876 – March 16, 1921, however, the latter date differs from the one in Rossiysky’s paper . Leonid Sobolev is also briefly mentioned in Professor V.N. Tsygan’s book , which mostly consists of A.I. Yarotsky’s papers. There is a “Curriculum vitae” in  in addition to Sobolev’s thesis, which is translated from the Latin as “life story”.
Here it is below in full:
“Leonid V. Sobolev, a clerk’s son, Russian Orthodox, was born in Trubachevsk of the Orlov province in 1876. He had his secondary education first at the Karachevskaya (Orlov province) pro-gymnasium and then Novgorod-Severskaya (Chernigov province) gymnasium from which he graduated in 1893. In the same year he entered the Emperor’s Military Medical Academy. Starting from 1896 he engaged in normal histology and mostly pathological anatomy supervised by Professor K.N. Vinogradov. In 1897 he was given an award named after Professor, actual Councilor of State T. Illinsky for presentation of his paper “On the Matter of Retentional Mucous Cysts of Large Intestines” presented at the conference in the Academy. In 1897 Sobolev graduated from the Academy as a “physician with flying colours” and was left for 3 years in the Academy on contest basis for advancement in the chosen field – pathological anatomy. Besides that he studied in Professor V.N. Sirotinin’s clinic for practical reasons at first. But soon, 2 months later, he stopped his studies in the clinic after finding this combination excessive and dedicated himself to theoretical work. He passed his exams for the Doctor of Medicine’s degree in the 1899/1900 academic year.”
After that there are three academic papers listed, including his thesis, with information that a preliminary notice of it was published in the «Еженедельник практической медицины» (Practical Medicine Weekly), 1900, no. 7 and in Centralblatt für allgemeine Pathologie und pathol. Anatomie, 1900, no. 6-7 in German. After getting the degree of the Doctor of Medicine, Sobolev was sent abroad for training for two years, in which Ivan P. Pavlov (1849-1936), who thought of him as his pupil, assisted him. I’ll quote Pavlov’s opinion of Sobolev (according to preface ): “… talking to Sobolev about his work I was amazed by a lot of ideas and deep thoughtfulness as to the matters touched upon by him… Sobolev impresses me as an outstanding person”. Such an opinion given by the great physiologist is worth a lot! Unfortunately it is not known which countries Sobolev visited, where he had his on-the-job training, which scientists he had contacts with. One can assume that he was in Germany, the doctors of which were the leading professionals in studying and treatment of diabetes in those times. It seems unquestionable that Sobolev had a good command of the German language as his papers starting from 1900 were regularly published in German medical journals including such prestigious journal as the Virchows Archive . When he returned home in 1903, he, as it was said above, was soon made an anatomist of the pathological anatomy department of the MMA and then he was made a privatdocent.
Let’s turn our attention to his thesis now, which he presented in 1901 when he was 25. It was titled “On the morphology of the pancreas when ligating its duct, in case of diabetes and some other conditions”. This paper is the basis of all the modern diabetology, and D.M. Rossiysky in his preface  gives a short review of it. I would like to tell about it in more detail. I, as a representative of exact sciences, admire Sobolev’s conscientiousness and logic of his research. I admire his diligence and knowledge of books and papers referring to his subject. The paper consists of two parts – experimental, or pathophysiological (70 pages) and pathoanatomical (50 pages). Sobolev formulates his hypothesis in the first part (quotations from  here and below): “Employing ligation of the pancreas duct, I had to expect atrophy of its digestive apparatus, but the islets of Langerhans, if they are elements different from the digestive apparatus both anatomically and functionally, were to survive”.
This conclusion was only one of the obtained important results; there were others, and in order to understand them let’s touch upon the pancreas structure. This organ performs a double function: the main mass of the pancreas secrets digestive juice or pancreatic juice (secret or enzyme), and the islets of Langerhans with four types of cells are its “endocrine part”, a whole biochemical factory, a source of vital hormones including insulin. Insulin enters blood and digestive enzyme goes along the special duct to the duodenum. Sobolev demonstrated that if you ligate this duct, thus excluding or weakening the first function of the organ, the pancreas starts atrophying, but the islet apparatus stays whole and continues to secret “X factor”, i.e. insulin. If you take a common pancreas, it is difficult to isolate pure insulin from its tissue, and the reason is clear for us today: insulin is a protein compound destroyed by digestive enzyme. And the resulting extract surely contains this enzyme and in big amounts — it is produced by the main mass of the pancreas. But ligation of the duct leads to fading away of the first pancreas’s function, there is no juice in it or nearly no juice, and the relative share of insulin increases – and consequently it is much easier to separate the required hormone from such a pancreas.
So, Sobolev performed the surgery , in the result of which it became possible to extract insulin from the atrophied pancreas of an animal. However, surgery is a very complicated way, inconvenient for mass production of medicine, and understanding that Sobolev went much further in his research. He offered to get insulin from calf pancreas as the islets of Langerhans are well-developed in calves and a number of other newborn animals and human babies, when digestive cells, producing pancreatic juice, are not in full operation yet. Consequently there is a lot of insulin and little juice in the pancreas of a young animal, a calf for example; it is a natural source of “X factor” not requiring preliminary surgery.
Why were the calves named the source of medicine? For purely practical reasons: the raw material is to come in big amounts and one has to take it from a slaughter house where pigs and cattle and not some exotic animals are slaughtered. And calves are slaughtered much more often that sucking pigs, and their pancreases are much bigger – these are the reasons explaining why bovine insulin was the first to appear in the world. Sobolev proved his hypothesis experimentally, ligating the ducts of nearly one hundred animals and investigating the changes in their pancreases in a day, two days, five days and so on up to one hundred days and two hundred days. Experiments included rabbits (27), dogs (14), cats (12), bulls, calves, sheep, pigs and even birds. Sobolev describes the surgical method and each experiment in detail, the pancreas structure of each species used in experiments, he even says that Professor I.P Pavlov was kind enough to operate three rabbits personally. Examination under a microscope at the final stage fully confirmed his hypothesis: “The same phenomenon is essentially repeated in all experiments, that is the atrophy of the parenchymatous elements of the pancreas except the islets of Langerhans”. The conclusion is followed by the detailed review of previous papers starting from Claude Bernard (1856) and Paul Langerhans; I.P. Pavlov’s, Joseph von Mering’s and Oscar Minkovsky’s, Gustave-Edouard Laguesse’s, A.I. Yarotsky’s papers and others are mentioned. Experiments when a part of the dog’s pancreas was transplanted under its belly skin are also described in this part as well as examination under a microscope of human foetus’s pancreas, newborn baby’s pancreas and ten month baby’s pancreas, newborn rabbit’s, guinea pig’s, calf’s pancreases. Sobolev writes: “The research entirely confirmed the original assumption that islets as internal secretion organs will be developed better in intrauterine life and the first period of extrauterine life in comparison with the digestive apparatus, which embryo does not need and which develops only later on because of that”.
The research of people is described in the pathoanatomical part: 18 patients not suffering from diabetes mellitus, with sclerotic changes in the pancreas at various stages (for example, because of syphilis or alcoholism), and 16 cases of people suffering from diabetes mellitus. We should emphasize here that Sobolev did not deal with live patients, he studied pancreases of dead people, i.e. specimen which the doctors he knew provided him with (he names each of them in his thesis and thanks them). Dead patients, from a baby to a woman of seventy, whose bodies were autopsied, were from the common people – unskilled workers, peasants, soldiers, rarely representatives of the lower middle class who were treated in various St. Petersburg hospitals (Obukhovskaya, Alexandrovskaya, Petropavlovskaya hospitals, Mariinskaya hospital for the poor, Clinical Military Hospital). When reading medical histories provided by Sobolev, you involuntary ask yourself a question, where and how were noblemen and merchants treated, for example, those suffering from diabetes? The doctors I know explained this to me saying that all hospitals mentioned above were the institutions for the poor, and patients with means were treated at home, by private doctors or could go abroad. Certainly in case of death their bodies were not autopsied.
After researching the pancreas samples of patients not suffering from diabetes, provided by his colleagues, Sobolev comes to the conclusion: “The islets of Langerhans are normal, i.e. they are fairly durable elements in case of those not suffering from diabetes, in relation to various harmful influences, in any case much more durable than the digestive apparatus of the pancreas”. As to those suffering from diabetes, he notices changes in the islet apparatus and writes: “I had pancreases of 15 diabetes cases and one case of acute glycosuria at my disposal”. And below: “In case of the said disease islets are exactly a very non-durable element”. It is followed by the review of papers on connection of diabetes with islet apparatus and critique of great Claude Bernard’s ideas in particular.
Analyzing Sobolev’s papers, one cannot but mention his schoolmate with whom he studied at the MMA together, a well-known Russian physician Alexander I. Yarotsky (1866-1944). Yarotsky was luckier, he lived a long life, he made his contributions to many fields of medical science including endocrinology and is rightly considered Sobolev’s predecessor. His Ph.D. thesis which he presented in the MMA in 1898 was reprinted in  together with an essay on his creative biography with comments prepared by Professor V.N. Tsygan. One of the main conclusions of the thesis is (quoted by ): “The islets of Langerhans do not represent changes of the usual parts of the pancreas. They are independent organs included in the pancreas mass. They take part in its secretion activities as one can judge by hypertrophy of adjoining to them parts and their richness in zymogenic granulosity under some conditions”.
By 1912 Sobolev published several more papers on pathological changes of the pancreas in case of diabetes, and most of these papers were published in German medical journals becoming the world science property. It is difficult to overestimate the importance of his publications — he not only found out the function of the islets of Langerhans but also showed a fairly realizable method of production of animal insulin. One would think that just a little bit more was required, and insulin could have been discovered in the very beginning of the XX century, and thousands of lives saved… But that did not happen. It happened only twenty years later and not in Russia, not in St. Petersburg but in Toronto, Canada, where Frederick Banting and Charles Best in torments and doubts repeated what Russian scientist Leonid Sobolev knew and foresaw.
A question arises: why? Why Leonid Sobolev was not the first in the world to prepare insulin from calf pancreas and did not start prolonging the lives of diabetics, getting the Noble prize for that? Was his illness a hindrance? But notwithstanding his multiple sclerosis he successfully taught MMA students and engaged in scientific research – this is reflected in two dozens of his papers dedicated not only to the islet apparatus but other matters as well (see the full list in ). Most likely, his illness had nothing to do with it and the main role was played by other circumstances. One can suggest three hypotheses as for the reason.
The first assumption is that, as a well-known German scientist P. Trendelenburg says in , “… his wonderful practical suggestions as to getting the substance from the islet apparatus of the pancreas were left unnoticed as laboratory technique and methods of chemical research were insufficiently developed yet for their carrying out”. This is fairly possible. As F. Banting’s and American doctors’ experience demonstrated in 1921-1922, it is impossible to check up the insulin effect without regular blood glucose tests. 20 ml of blood (nearly one and a half table spoons) were required for such test in 1910, and in 1920 it became possible to have such test done with 0.2 ml, so it became practically realizable. On the other hand, American endocrinologist Sam Wentworth  told me a story about a woman suffering from diabetes, who found herself in China during World War II, where there was no insulin. Having neither knowledge of chemistry, nor any equipment, she learnt to prepare insulin from rabbits’ pancreases and saved her life. Possibly, this could have been realized even in the beginning of the XX century, couldn’t it?
The second assumption is L.S. Salyamon’s . He writes that Claude Bernard’s (1813-1878) erroneous theory was predominant in European diabetology in the end of the XIX century and the beginning of the XX century. Bernard thought that diabetes is a nervous disease having effect on liver and making it secret glucose into blood. Bernard thought that the pancreas secrets digestive enzyme only and did not ascribe it any role in the metabolism. Professor V.V. Pashutin, the head of the MMA and an outstanding pathophysiologist, and his students, including Professor K.N. Vinogradov who supervised Sobolev’s work on his thesis, supported this theory. Salyamon writes that “… the scientists of the Military Medical Academy were very interested in the diabetes problem, they researched it themselves and did not notice how their student solved the problem”. And he adds sarcastically: “It is unlikely that Sobolev’s research could give a lot of pleasure to the top Russian authorities who engaged in the diabetes problem. Sobolev demonstrated the groundlessness of the direction of their work in which they had engaged for many years. L.V. Sobolev fairly convincingly criticizes the hypothesis of “genius researcher” Claude Bernard in his thesis, though civilly, and mentions V.V. Pashutin, i.e. his teacher and the head of the Academy, as a follower of the erroneous concept.”
So, we cannot exclude that Sobolev was a victim of the axiom “the superior is always right”. In Salyamon’s opinion, he had no opportunity to bring his discovery to the logical end as such an opportunity requires the availability of means – laboratory equipment, animals to experiment on, assistants and financing of the work. In other words, too clever Sobolev was “suppressed” and they did it really strong. Commenting this state of affairs, Salyamon writes: “L.V. Sobolev’s work in his Motherland took place without leaving a trace, so that his name was as a rule not mentioned in local printed matter. L.V. Sobolev’s name became known here after publication of the volume two of the manual on endocrinology “Hormones” written by P. Trendelenburg. Conscientious analysis of the history of discovery of insulin made Trendelenburg underline that the main ideas of F. Banting’s work had been formulated by L. Sobolev 20 years earlier”.
I’ll risk to make the third assumption myself. At the first stage of research, when preparing his thesis, Sobolev, in contrast to F. Banting, probably did not set a target to create a medicine but engaged in a more general problem: to find out the function of the islets of Langerhans and their regulating influence on the carbohydrate metabolism. He was not a practical physician but a scientist engaged in medicine, he did not deal with live – still alive! – patients. Such people in Toronto so to say breathed in Banting’s back. Banting knew that he had to prepare a medicine; Sobolev knew that he had to solve an academic problem. It is possible that had Sobolev been so strongly pressed by patients as Banting and people working with Banting in Toronto, he could have done everything in his power to create a medicine. But it seems that there was no such pressure. I’ll risk to suppose that diabetes mellitus was not very widespread in the Russian Empire at the time, infectious diseases such as typhus, dysentery, tuberculosis were threatening with much more serious troubles. It is known  that in the beginning of the XX century diabetes was especially often found with well-to-do people of the richest countries of the world, the USA and Germany, which was associated with plenty of food in particular. Russia was far from flourishing in this sense. Those who lived in poverty and restricted their diet to simple products seldom had diabetes. This conclusion is supported by the fact that during wars and hunger accompanying them the number of diabetes cases decreases. It is possible that this illness in Russia in the beginning of the XX century was more likely an academic problem – taking into account that rich diabetics could live and be treated either in Germany or France. It means that Sobolev’s work was not the matter of current, topical interest, and he did not have a strong motivation to switch from his teaching to treating. In my opinion, only well-to-do patients and financing from patrons could be such a motivation.
Now let’s discuss one other matter: did Banting know about Sobolev’s work? And if he did, why doesn’t he give references to it? Professor Rossiysky speaks about it in , definitely offended, saying that Sobolev’s papers were published in German journals and consequently were available to the widest scientific community.
The date of Sobolev’s priority is May 3, 1902. But Canadian historian Michael Bliss, the author of a substantive research , says that the idea of ligating of the pancreas ducts came to Banting on October 30, 1920 after he read M. Barron’s paper  published in the Surgery, Gynecology and Obstetrics in 1920. Consequently Banting did not know about Sobolev’s papers. And what is more Sobolev is not mentioned at all in Bliss’s book – I underline: in the book published in 1982 (when the priority paper was already quoted 56 times in non-Russian works all over the world!) — though the author writes about other scientists aspiring to the discovery of insulin in detail (in particular about the papers of 1920-1921 by Romanian pathophysiologist Nicolae Paulescu). Disputes do not stop either as to the priority of the latter in the discovery of “pancrein-insulin” . As for the connection between diabetes and affection of the islets of Langerhans, the idea, as Bliss says, was first formulated in 1901 by Dr. Eugene Opie who served at the Johns Hopkins University and published a respective paper only in 1910. I believe Bliss as to the fact that Sobolev’s name was in oblivion in America even more than in Russia. Probably Banting knew nothing of his work. In contrast to generally educated Sobolev, Banting did not read in German, and Best translated papers from French to him, as this language “was a little known” to him as it is said in  . So we should not feel offended by Banting. Let’s remember a saying: no man is a prophet in his own land.
I have no information as to Sobolev’s illness. Doctors told me that multiple sclerosis often affects young people at the age of 20-25, so Sobolev could fall ill while abroad or soon after he returned home. The illness is incurable and awful; it leads to paralysis, and Leonid V. Sobolev died on one of the days of 1919 in exactly such a state, nearly fully paralyzed. He died in Petrograd, when the Civil War was in full swing, in the former capital of the Empire, when half of its inhabitants had left it because of hunger. But if that happened in 1921 as the authors of  state, the state of affairs in the city was not much better. Nearly a hundred years later Leonid V. Sobolev stays a mysterious and tragic figure for us in many ways. We can see what he did in the field of knowledge, but what about the rest?! I understand that my essay puts more questions than gives answers to them. Was he married, are there any descendants?.. If he did not have any family, who took care of him? He did need help because of his illness, especially in his final years. Where did he live and what kind of life was that, poor or relatively well-to-do?.. What ideas came to his mind — did he understand the greatness of his achievement and the evil joke his fate played on him?.. What did people close to him and his colleagues think of him?.. And finally, why didn’t great physiologist Pavlov who had such a flattering opinion of him treat him kindly and take him under his wing, didn’t make him bring his work to a logical end, to a healing medicine?..
I think that the life of Leonid V. Sobolev still waits for its researchers. Look at the photos [Figures 3-4] – here he is surrounded by his students who studied at the MMA, a man with the face of a Russian intellectual, concentrated, deep in thought, a little sullen and possibly tired… These photos are one hundred years old, they are very rare photos from the archives of St. Petersburg doctors, Professors Vasily N. Tsygan [Figure 5] and Vsevolod A. Tsinzerling [Figure 2 (center) and 3-4], to whom I am very grateful. The person on the left in Figure 3 is Vsevolod D. Tsinzerling (1891-1960), the grandfather of Vsevolod A. Tsinzerling and an outstanding Russian pathologist in later years. Until recently there was no information about Leonid V. Sobolev in Russian Wikipedia. Now there is an article about him – it was written by me and posted by my colleague, a man experienced in computer science. I hope that professionals having access to documents unknown to me will add something to my writings – as geniuses should not remain unknown.
Concluding this paper, I would like to draw your attention to a nearly mystic parallel between the fates of Leonid Sobolev and Paul Langerhans. Both of them were very talented people, they made epoch-making discoveries when they were young, they stayed dedicated to science, they both suffered from incurable diseases and died nearly at the same age – Langerhans died 5 days before he was 41, Sobolev died at 42-43 or possibly 45. But Langerhans was luckier – he died on the island of Madeira, a wonderful island of eternal spring, he left for the eternity in the arms of the woman he loved .
Who cried over Leonid Sobolev?.. Who closed his eyes?.. Who laid him to rest?..
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