Robert Adolph Armand Tigerstedt (28 February 1853 – 12 February 1923) was a Finnish medical scientist and physiologist. With his student Per Bergman, he discovered renin at the Karolinska Institute, Stockholm, Sweden, in 1898. Renin is a component of the renin–angiotensin system which regulates blood pressure, salt and water homeostasis and is an important therapeutic target. Tigerstedt is also recognised as an educator, author and social campaigner.
Biography
Early life Tigerstedt was born in Helsinki on 28 February 1853. His parents were Karl Konstatin Tigerstedt and Evelina Theresia Tigerstedt (née Degerman). Karl Konstatin was a professor of history at the University of Helsinki.
Adult life Tigerstedt matriculated from Åbo Gymnasium in Turku in 1869, and then studied physical and natural sciences at the University of Helsinki, where he was taught by the notable chemist Carl Axel Arrhenius. He graduated from the University of Helsinki with a Master of Arts degree in 1873 and added a Bachelor of Science degree in 1876. Subsequently, Tigerstedt studied medicine from 1876 to 1880. In 1878 he married his Ukrainian cousin, Ljuba Ludmila Martinau (1850–1935) and their first child, Maria (Ljubow Marie Nathalie Eveline (1879–1975)), was born while Tigerstedt was still a medical student. Two further children, Carl Christian Oskar Robert (1882–1930) and Margareta Wilhelmina Maria (1891–1980) followed. After completing his medical studies, in 1881 Tigerstedt submitted his doctorate entitled 'über Mechanische Nervenreizung' (On the mechanical stimulation of the nervous system) in Helsinki; however due to opposition from Konrad Hällstén, the professor of Physiology at Helsinki, he was unable to get a job in Helsinki and in 1881 he moved to Stockholm to become a demonstrator in the newly founded department of physiology headed by Christian Lóven in the Karolinska Institute.
Stockholm Tigerstedt remained at the Karolinska for the next 20 years, initially as Lóven's assistant and then as professor of physiology when Lóven retired in 1886. Tigerstedt undertook most of his major scientific work, including the discovery of renin during his two decades at the Karolinska Institute in Stockholm. His early research was mainly into nerve and muscle physiology, but in 1881 he started work on the physiology of the circulation in Carl Ludwig's laboratory. While there, in 1884, he showed that independent atrial and ventricular rhythms could be generated in mammalian hearts after damaging the atrium. Alongside his work on the heart and circulation, he also performed important studies in metabolism and nutrition, and with Klas Gustaf Anders Sondén designed the Sonden-Tigerstedt respiration chamber. Tigerstedt also began writing his classic 'Lehrbuch der Physiologie des Menschens (Textbook of Human Physiology)' during this period. His friend Ivan Pavlov called it 'the greatest textbook of physiology ever written' and it exerted a considerable worldwide influence. Tigerstedt was fluent in several languages, edited four scientific journals concurrently, authored numerous articles in popular magazines, wrote an extensive range of biographical works on famous scientists, and made important contributions to modernizing the teaching of medical sciences in Stockholm and later in Helsinki. He was a teetotaller and was a leading figure in the temperance movement in Finland and abroad, although he was opposed to prohibition. Tigerstedt was a member of Svenska Nykterhetssällskapet (the Swedish Temperance Society) and served as its vice president from 1893.
Helsinki In 1901 Tigerstedt left Stockholm to take up the chair in Physiology at Helsinki University following the retirement of Hällstén. At this time Finland was not an independent state and Tigerstedt may have had nationalistic motives in returning; certainly the return of such a prestigious scientist was hailed in Finland. In Helsinki Tigerstedt continued his work as a physiologist, educator, author and remained active in social reform. From 1916–1919 he was Dean of the Faculty of Medicine at Helsinki. In 1918 Finland achieved independence from Russia and Tigerstedt retired from the university in 1919, although he continued to lecture. Tigerstedt's work on nutrition may have been used to inform rationing during the war shortages, and after the Finnish Civil War he was appointed chief physician for the Ekenäs prison camp. He and his son Carl wrote critical reports on conditions in the prison camps; in one in August 1918 Tigerstedt noted that 'between 6 July and 31 July 1918, the number of detainees that were held in the camp at Tampere and the adjacent prison varied between 6,027 and 8,597. 2,347 prisoners died in these twenty-six days and the weekly mortality-rate among detainees was as high as 407 per thousand.' This report was leaked and published in various national and international newspapers to the embarrassment of the government. Tigerstedt also served as chairman of the committee for assistance to Finnish children (1919–1921), and served on other national committees related to the Finnish army and air force. In his retirement Tigerstedt continued to write; his encyclopaedic Physiology of the Circulation was published shortly before his death from a heart attack in 1923.
Discovery of renin Tigerstedt's work on renin was probably inspired by Brown-Sequard's work examining the effect of organ extracts on physiological function. In 1898 Tigerstedt and Bergman made extracts of rabbit kidney and injected them into rabbits. They observed that even a very small amount of the extract increased blood pressure (probably measured by Ludwig's kymograph). They showed that the substance, which they called renin, was present in extract of renal cortex or venous blood from the kidney but not in urine, extract of renal medulla or the arterial blood supplying the kidney. They further showed that the pressor effect of renin did not require an intact nervous system and that it was not accompanied by a change in heart rate. They concluded that renin caused vasoconstriction, but the mechanism was unknown. This question would remain unresolved until the work of Harry Goldblatt, Irvine Page, Eduardo Braun-Menenez and others in the 1930s.
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