ESSAY｜TOWARD JES 100TH ANNIVERSARY
Vasopressin, my best friend for life & Dr. Gary L. Robertson, the founder of the vasopressin world
2022 Volume 69 Issue 11 Pages 1273-1279
Details
2022 Volume 69 Issue 11 Pages 1273-1279
First of all, I would like to say that this article is not a scientific article but a personal essay.
When I was still a medical student at Kobe University, there was a curriculum called an introductory research course in which everyone belonged to the basic laboratory for half a year. Since I was aiming to be a clinician, I chose a pathology class that is close to the clinic. I started to learn about the pathological findings of the hypothalamus under the guidance of Dr. Kichihei Miyasaki in 1970. The case I was in charge of the analysis was a young woman with a brain tumor who presented with brain dysfunction, visual field deficit, polydipsia and polyuria. As a medical student just 20 years old, I strongly felt that she regretted the ephemeral short life, and it was a burden to proceed with the pathological analysis of her brain. The task I was given was to measure the number of cells in the supraoptic nucleus and paraventricular nucleus in the hypothalamus. The purpose of the research was to understand the pathogenic mechanism of central diabetes insipidus that resulted in polydipsia and polyuria. I spent day after day by Nissl staining using continuous sections of the hypothalamus and counting the number of cells under a microscope. At the same time, I read a lot of papers in the library to learn more about central diabetes insipidus, but I never imagined that the vasopressin would be a best friend of my life.
I would explain to make it easier for readers to understand the historical background of the time. The PC8000 series of Japanese personal computers was released in 1979, the internet was experimentally started in 1984, and e-mails could be sent in Japanese in 1993. Therefore, when I was a student, all the literature was copied in the library, and all information should be sent by letters, faxes and telephones. Researchers had struggled in an information maze that you could not imagine now. And for the literature search, I had to use a thick book like a dictionary called Index Medicus stored in the library. Researchers were forced into an endless battle, first they open the relevant page of the search keywords and then look at a myriad of literature titles listed.
The result of hard work, I was able to publish a paper as a co-author of Dr. Miyasaki in the official journal of the Japan Endocrine Society in 1973 [1] after accumulating microscopic operations and a huge amount of time-consuming literature searches (Fig. 1). I learned importance of compiling a dissertation through the study as a beginner in scientific research.
My first co-authored paper in Folia Endocrinol Jap, 1973
I obtained a medical doctor’s license in 1974 and started the training course of internal medicine at Nagoya University in my hometown. I was busy with clinical training every day, but my interest in vasopressin only increased. So, since 1975, I contacted Dr. Mitsuo Ukai who had been studying vasopressin at Nagoya University as a surgeon after the training hours of internal medicine. My interest was to elucidate the role of vasopressin in various water metabolism disorders, and it was clear that the only way to achieve this was to correctly measure plasma vasopressin. But how do I measure vasopressin? I read many literature about vasopressin measurement and learned that bioassay was the only measurement method I could do now. I started working with Dr. Ukai for advice to learn bioassay.
Here is a brief description of the bioassay procedure (Fig. 2). First, 13% ethanol is given via a gastric catheter (5% BW) to anesthetize the rat, and after anesthesia, skin incisions are made and catheters are inserted into the bladder and femoral vein, respectively. Then, a maintenance infusion solution (2.5% glucose and 3% ethanol) is continuously injected from the vein and wait for the rat’s urine volume to become constant. After the urine volume stabilizes, standard vasopressin of 3 to 5 different concentrations is sequentially injected from the lowest concentration, and the urinary electrical conductivity is continuously monitored to create a standard curve. The reason for administering ethanol with bioassay is not only to act as an anesthetic, but also to suppress endogenous vasopressin. Although the principle of vasopressin bioassay is simple, effect of high-concentration vasopressin lasts for 6 hours or more, so it takes at least 12 hours to inject all concentrations and create a standard curve. However, the purpose is not to draw a standard curve, so after that, samples extracted from the blood are injected and the urine reactions are measured. Unfortunately, the reality is sad, rats have already been anesthetized for more than 12 hours. Even if a standard curve could be drawn, it is disastrous that the rat is already weakened, and the urinary response disappeared at the time of sample measurement. Bioassay gives severe suffering not only for rats, but also for me, who measure all night long. Moreover, even if the sample could be measured successfully, the assay sensitivity was extremely low. It was a dream to distinguish between central diabetes insipidus and healthy subjects with this measurement method. Therefore, bioassay was only practical for high-concentration measurement such as the content of tissue from vasopressin-producing tumors. There was a mass of dark clouds for the analysis of vasopressin secretion at that time.
Procedure for vasopressin bioassay
Since then, I went to the library like a habit to collect literature of vasopressin assay from around the world. As a result, I found an American physician named Dr. Gary L. Robertson was producing marvelous research results. He developed the long-awaited dreamlike high-sensitivity vasopressin RIA in 1973 [2] and used this RIA to clarify the dynamics of vasopressin release one after another. His research had enabled accurate clinical diagnosis of various water metabolism disorders as well as analysis of physiological role of vasopressin in 1977 [3]. As I read these reports, I was heartily impressed as if the god of vasopressin had descended.
Today, everyone would immediately send an email easily and ask something without any hesitation. However, at that time, the United States was a faraway world, and the first thing that came to my mind was a reckless attempt to launch the RIA of vasopressin by myself. And for several years from 1976 when I started, I had been on the road of hardship. At that time, RIA was being developed targeting many other hormones. However, vasopressin was very difficult to develop RIA system, because vasopressin is a small peptide hormone with a molecular weight of about 1,000. It is theoretically difficult to produce the high-performance antigen required for RIA. Therefore, I used vasopressin as a hapten, and conjugated with thyroglobulin to immunize the sole of rabbits and create the antibody. After several years of trial and error, I developed my own RIA system for vasopressin in 1981 [4] (Fig. 3). Unfortunately, the sensitivity of this RIA was completely different from that of Dr. Robertson’s assay that I expected. In other words, this RIA had a limit in accurately diagnosing the diseases in which vasopressin secretion was reduced. During the process of setting up this RIA, I reread Dr. Robertson’s literature many times and reaffirmed the greatness of his measurement system and came to the conclusion that I had no choice but to get direct guidance from Professor Robertson of the University of Chicago. I had never met him in person, but I sent him a letter asking him to be instructed for vasopressin research. And I still cannot forget how happy I was when I received the long-awaited letter and found the word OK in it.
Representative standard curves for RIA of vasopressin
I and my family arrived at Chicago O’Hare Airport in June 1981 and set foot in the Americas for the first time in our life. Dr. Robertson kindly came all the way to pick us up at the airport. Because I had only seen his name in the literature, I was worried about what kind of person Dr. Robertson was. My first impression was that he would get angry, but Colonel Sanders, Kentucky Fried Chicken (KFC), came to my mind. Because KFC’s first store in Japan opened in my hometown of Nagoya in 1970, which probably led to my association. Above all, his own car was Honda Accord, not a large American car, I was happy to know that he is a Japanese car fan.
At that time Chicago was known to be a dangerous city for Japanese, especially the University of Chicago was in the southern area of Chicago where was particularly unsafe. The campus of the University of Chicago had many school buildings with an elegant appearance that was as historic as another world. Dr. Robertson’s laboratory was set up in the School of Medicine and had a cozy atmosphere with less than 10 staff. I basically studied analysis on Brattleboro rats that develop congenital central diabetes insipidus and studied the effects of opioid peptide on vasopressin secretion. The role of opioid peptide had received a great deal of attention in the central nervous system. Then, on a daily basis, I also extracted plasma vasopressin and measured vasopressin by the RIA with some technicians. In particular, I was taught everything by Ms. Mary Beth Gaskill who was chief technician at Dr. Robertson’s laboratory. Although she was very busy because she knew all the work of the laboratory, she taught me kindly and politely. Actually, she was not just a technician, but a scientist with a great deal of knowledge of vasopressin. I convinced from deep in my heart that these talented people supported clinical research and developed many important studies in the United States.
Of course, I was absorbed in individual research at Dr. Robertson’s laboratory, moreover I had one-on-one meetings with Dr. Robertson several times a month. Through the dialogue with him, I was able to learn about various approaches to vasopressin and it was also an opportunity to learn about Dr. Robertson’s deep love for vasopressin, so I also wanted to be another vasopressin’s best friend. A minor problem was that Dr. Robertson only listened to half of my dubious English and then he had the feat of inferring and understanding the whereabouts of the second half of the story. So fortunately or unfortunately, my English conversation ability did not improve.
I was engaged in basic research at the University of Chicago in principle, but case conference for the endocrine sections was held several times a month on Saturday mornings. I was also looking forward to participating in this conference, and I was able to get a glimpse of the clinical practice in the United States by watching the discussion proceed in a free atmosphere.
While studying at the University of Chicago, I accumulated a certain amount of experience not only vasopressin-related knowledge but also future challenge in the neuroendocrine area. However, in both basic and clinical studies, I realized again that I could not do anything unless I could accurately measure vasopressin when I returned to Japan. I was rather hesitant about what kind of method should be used for research in Japan.
I returned to Nagoya University in October 1982 and worked on setting up the experimental system for a while and improving the RIA system that I developed myself by changing various conditions. However, days have passed without success since I started my new efforts. In the meantime, good news that shakes the world came in the summer of 1983. It was a contact that Mitsubishi Yuka Co. produced an antibody that enables high-sensitive vasopressin RIA system, and they expected to discuss how to introduce it to clinical examination. The detail of this measurement system was reported by Sakurai et al. in 1985 [5]. The sensitivity of this system is 0.15 pg / mL, which means that it can stably measure a surprisingly low concentration of vasopressin as in central diabetes insipidus (Fig. 3). They asked Dr. Robertson to examine the correlation with his measurement system. As a result, the correlation coefficient was extremely high at 0.997, and Dr. Robertson gave a high evaluation. I think that this measurement system enabled the diagnosis of central diabetes insipidus in Japan where any vasopressin RIA system had never made an accurate diagnosis before. Moreover, it would be possible to diagnose various water metabolism disorders.
In cooperation with Mitsubishi Yuka Co., we first worked on the evaluation of vasopressin secretion in normal subjects and patients with central diabetes insipidus to prove its effectiveness in the daily clinical practice. Until then, the diagnostic method for central diabetes insipidus in Japan was the Carter-Robbins test, which is an indirect method for estimating vasopressin secretion by changes in urine osmolality after a large dose of 2.5% hypertonic saline infusion. This method had many problems in proper diagnosis, diagnosis often modified by renal function. We have used a small dose of 5% hypertonic saline to evaluate plasma vasopressin concentration in correlation with plasma osmolality. Dr. Robertson obtained more data on 3% hypertonic saline loading in his earlier studies, but later revised to 5% hypertonic saline administration, which we also referred to. We set a standard range of vasopressin secretion for elevated plasma osmolality in healthy subjects (Fig. 4). Next, we examined the vasopressin secretion in patients with polyuria and revealed that both qualitative and quantitative diagnoses of central diabetes insipidus can be made in 1986 [6] (Fig. 4). Mitsubishi Yuka Co. applied for approval of these clinical data to the Japanese Ministry of Health and Welfare (at that time). This vasopressin-RIA system was approved in 1987 as the first official test kit for vasopressin measurement in Japan. After that, the Ministry of Health and Welfare recognized this 5% hypertonic saline loading test as a formal diagnostic procedure for central diabetes insipidus. We are very pleased that the test had been widely used for the evaluation and diagnosis of water metabolism disorders.
Relationship of plasma vasopressin to plasma osmolality during 5% hypertonic saline loading
In our laboratory, Dr. Yasumasa Iwasaki et al. were able to examine changes in vasopressin secretion in Sheehan’s syndrome [7], myxedema [8], pregnancy [9], etc. and reported many new findings (Fig. 5). The kit was also released overseas, Dr. Robertson supported its use as a clinical adviser in the United States. In this way, this vasopressin kit has been used around the world as the only tool that can be used for clinical diagnosis, clinical research, and even basic research. However, the vasopressin antibody, which plays the most important role in the measurement system, was gradually depleted, and unfortunately Mitsubishi Yuka Co. ended the sale of this kit 26 years after approval.
Our representative studies-1
I had the opportunity to establish the vasopressin research laboratory at Nagoya University. Many valuable studies had been done on the vasopressin area by the excellent endocrine physicians at Nagoya University (Figs. 5, 6). Unfortunately, I cannot write the details in this article due to space limitations, but I would like to express my heartfelt gratitude to everyone involved by listing representative studies before the beginning of the 21st century [10-16].
Our representative studies-2
I have been walking with vasopressin for almost half a century since I was a medical student. It is difficult to evaluate how my research played a role in the development of clinical medicine and basic research. However, in Japan, there is a saying that momo, kuri (peach, sweet nut) 3 years and kaki (persimmon) 8 years (it often takes time to bear the fruit of one’s actions). Anyway, I think I could at least clear this word. I’m now living a life like Carpe diem (every day is a good day) searching for vasopressin on MEDLINE on my desk with a cup of coffee.
There are many memories with Dr. Robertson. The photo was taken with Dr. Robertson (on the left), Dr. Iwasaki (on the back row) and me (on the right) at the dinner party of the 3rd International Vasopressin Conference held in Montpellier, France in 1990 (Fig. 7). Especially, he visited Japan three times to give the lecture. First, he was invited to a special lecture at the 57th Annual Congress of JES on May 18, 1984 (Tokyo) and gave a lecture on the theme of thirst and vasopressin in disorders of salt and water balance. He then visited Japan in 1994 and 2003 to speak as a special speaker at international conferences. He always presented the latest content of the vasopressin study to doctors and researchers in the endocrine area of Japan and made the importance of posterior lobe function in Japan.
With Dr. Robertson at the conference dinner in France in 1990
Finally, shortly before I retired from Nagoya University, I was able to present a review article of treatment of central diabetes insipidus to Journal of Clinical Endocrinology & Metabolism [17] with my respected Dr. Robertson, the founder of vasopressin world. It is a dream story that I could not have been imagined half a century ago. I would like to express my heartfelt gratitude to Dr. Robertson and all the researchers who worked hard with me to make it possible.
Yutaka Oiso
Honorary Member
Professor Emeritus, Nagoya University
E-mail: yutakamd@med.nagoya-u.ac.jp
Careers in JES
2019– Honorary Member
2015– Senior Councilor
2007–2015 Director (Education and Career Development)
2007–2010 President for Tokai Regional Branch
1986– Councilor
1972– Member
Activities in JES
2012 Chair, 85th Annual Congress of JES
2008 Chair, 26th JES Summer Seminar on Endocrinology & Metabolism
2005 Chair, 5th Annual Meeting of JES Tokai Regional Branch
JES Awards
2014 13th JES Award
