International Neuroendocrine Federation: Year 2020 in Review

In this “Year 2020 in Review”, we highlight a few major achievements selected from the work of 10 member societies of the International Neuroendocrine Federation, encompassing national, regional and thematic societies from around 30 countries. Despite the Covid‐19 pandemic, many remarkable breakthroughs have come to light in 2020, testifying to the dedication of our researchers and providing a ray of optimism as we head towards the 10th International Congress of Neuroendocrinology (ICN) to be held in Glasgow in August 2022.

History of hypothalamic research: "The spring of primitive existence"

The central brain region of interest for neuroendocrinology is the hypothalamus, a name coined by Wilhelm His in 1893. Neuroendocrinology is the discipline that studies hormone production by neurons, the sensitivity of neurons for hormones, as well as the dynamic, bidirectional interactions between neurons and endocrine glands. These interactions do not only occur through hormones, but are also partly accomplished by the autonomic nervous system that is regulated by the hypothalamus and that innervates the endocrine glands. A special characteristic of the hypothalamus is that it contains neuroendocrine neurons projecting either to the neurohypophysis or to the portal vessels of the anterior lobe of the pituitary in the median eminence, where they release their neuropeptides or other neuroactive compounds into the bloodstream, which subsequently act as neurohormones. In the 1970s it was found that vasopressin and oxytocin not only are released as hormones in the circulation but that their neurons project to other neurons within and outside the hypothalamus and function as neurotransmitters or neuromodulators that regulate central functions, including the autonomic innervation of all our body organs. Recently magnocellular oxytocin neurons were shown to send not only an axon to the neurohypophysis, but also axon collaterals of the same neuroendocrine neuron to a multitude of brain areas. In this way, the hypothalamus acts as a central integrator for endocrine, autonomic, and higher brain functions. The history of neuroendocrinology is described in this chapter from the descriptions in De humani corporis fabrica by Vesalius (1537) to the present, with a timeline of the scientists and their findings.

Testosterone administration in human social neuroendocrinology: Past, present, and future

Over the past 20 years, social neuroendocrinology researchers have developed pharmacological challenge paradigms to assess the extent to which testosterone plays a causal role in human psychological and behavioural processes. The current paper provides a brief summary of this research and offers recommendations for future research examining the neuroendocrine mechanisms underlying human behaviour.

Estrogenic regulation of memory: The first 50 years

This review highlights fifty years of progress in research on estradiol's role in regulating behavior(s). It was initially thought that estradiol was only involved in regulating estrus/menstrual cycles and concomitant sexual behavior, but it is now clear that estradiol also influences the higher order neural function of cognition. We provide a brief overview of estradiol's regulation of memory and some mechanisms which underlie its effects. Given systemically or directly into the hippocampus, to ovariectomized female rodents, estradiol or specific agonists, enhance learning and/or memory in a variety of rodent cognitive tasks. Acute (within minutes) or chronic (days) treatments enhance cognitive functions. Under the same treatment conditions, dendritic spine density on pyramidal neurons in the CA1 area of the hippocampus and medial prefrontal cortex increase which suggests that these changes are an important component of estrogen's ability to impact memory processes. Noradrenergic, dopaminergic and serotoninergic activity are also altered in these areas following estrogen treatments. Memory enhancements and increased spine density by estrogens are not limited to females but are also present in castrate males. In the next fifty years, neuroscientists need to determine how currently described neural changes mediate improved memory, how interactions among areas important for memory promote memory and the potential significance of neurally derived estrogens in normal cognitive processing. Answering these questions may provide significant advances for treatment of dementias as well as age and neuro-degenerative disease related memory loss.

Hormones and Behavior: An emergent journal

Hormones and Behavior was founded in 1969 by Frank A. Beach and members of his laboratory. Prior to the founding there was no journal specifically devoted to hormones and behavior. This paper explores how the editorship of the journal has developed over the first 50 years, going from the initial three male editors to the current female editor-in-chief, five associate editors (four men and one women), and a 98 member editorial board consisting of 46 men and 52 women. Early concerns that a specialty journal of hormones and behavior might ghettoize the field did not come to pass and the visibility and impact of the journal has helped to expand the spread of the field, now called Behavioral Neuroendocrinology. This growth accelerated with the creation of the Society for Behavioral Neuroendocrinology in 1996 and the adoption of Hormones and Behavior as the Society's official journal. The growth has been striking with total annual citations going from 1321 per year in 1997 to the current 10,874 annual citations. The journal's impact factor (JIF), 1.42 in 1997, has increased to the current (2018) JIF of 3.95. Over the 50 years of Hormones and Behavior's existence it has emerged as a principle voice of the Hormones and Behavior community. It will be intriguing to see what the next 50 years reveals.

Sexual differentiation of brain and other tissues: Five questions for the next 50 years

This paper is part of the celebration of the 50th anniversary of founding of the journal Hormones and Behavior, the official journal of the Society for Behavioral Neuroendocrinology. All sex differences in phenotypic development stem from the sexual imbalance in X and Y chromosomes, which are the only known differences in XX and XY zygotes. The sex chromosome genes act within cells to cause differences in phenotypes of XX and XY cells throughout the body. In the gonad, they determine the type of gonad, leading to differences in secretion of testicular vs. ovarian hormones, which cause further sex differences in tissue function. These current ideas of sexual differentiation are briefly contrasted with a hormones-only view of sexual differentiation of the last century. The multiple, independent action of diverse sex-biasing agents means that sex-biased factors can be synergistic, increasing sex differences, or compensatory, making the two sexes more equal. Several animal models have been fruitful in demonstrating sex chromosome effects, and interactions with gonadal hormones. MRI studies of human brains demonstrate variation in brain structure associated with both differences in gonadal hormones, and in the number of X and Y chromosomes. Five unanswered questions are posed as a challenge to future investigators to improve understanding of sexual differentiation throughout the body.

The behavioral neuroendocrinology of maternal behavior: Past accomplishments and future directions

Research on the neuroendocrine-endocrine-neural regulation of maternal behavior has made significant progress the past 50 years. In this mini-review progress during this period has been divided into five stages. These stages consist of advances in the identification of endocrine factors that mediate maternal care, the characterization of the neural basis of maternal behavior with reference to endocrine actions, the impact of developmental and experiential states on maternal care, the dynamic neuroplastic maternal brain, and genes and motherhood. A final section concludes with a discussion of future directions in the field of the neurobiology/neuroendocrinology of motherhood.

How technical progress reshaped behavioral neuroendocrinology during the last 50 years… and some methodological remarks

The first issue of Hormones and Behavior was published 50 years ago in 1969, a time when most of the techniques we currently use in Behavioral Endocrinology were not available. Researchers have during the last 5 decades developed techniques that allow measuring hormones in small volumes of biological samples, identify the sites where steroids act in the brain to activate sexual behavior, characterize and quantify gene expression correlated with behavior expression, modify this expression in a specific manner, and manipulate the activity of selected neuronal populations by chemogenetic and optogenetic techniques. This technical progress has considerably transformed the field and has been very beneficial for our understanding of the endocrine controls of behavior in general, but it did also come with some caveats. The facilitation of scientific investigations came with some relaxation of methodological exigency. Some critical controls are no longer performed on a regular basis and complex techniques supplied as ready to use kits are implemented without precise knowledge of their limitations. We present here a selective review of the most important of these new techniques, their potential problems and how they changed our view of the hormonal control of behavior. Fortunately, the scientific endeavor is a self-correcting process. The problems have been identified and corrections have been proposed. The next decades will obviously be filled with exciting discoveries in behavioral neuroendocrinology.

New concepts in the study of the sexual differentiation and activation of reproductive behavior, a personal view

Since the beginning of this century, research methods in neuroendocrinology enjoyed extensive refinements and innovation. These advances allowed collection of huge amounts of new data and the development of new ideas but have not led to this point, with a few exceptions, to the development of new conceptual advances. Conceptual advances that took place largely resulted from the ingenious insights of several investigators. I summarize here some of these new ideas as they relate to the sexual differentiation and activation by sex steroids of reproductive behaviors and I discuss how our research contributed to the general picture. This selective review clearly demonstrates the importance of conceptual changes that have taken place in this field since beginning of the 21st century. The recent technological advances suggest that our understanding of hormones, brain and behavior relationships will continue to improve in a very fundamental manner over the coming years.

Thirty years of neuroendocrinology: Technological advances pave the way for molecular discovery

Since the 1950s, the systems level interactions between the hypothalamus, pituitary and end organs such as the adrenal, thyroid and gonads have been well known; however, it is only over the last three decades that advances in molecular biology and information technology have provided a tremendous expansion of knowledge at the molecular level. Neuroendocrinology has benefitted from developments in molecular genetics, epigenetics and epigenomics, and most recently optogenetics and pharmacogenetics. This has enabled a new understanding of gene regulation, transcription, translation and post-translational regulation, which should help direct the development of drugs to treat neuroendocrine-related diseases.

30 years after: CNS actions of prolactin: Sources, mechanisms and physiological significance

Our understanding of the neural actions of prolactin (PRL) and its biochemical basis has expanded greatly over the past three decades. During this time, major progress has been made, including clarification of how PRL accesses the brain, identification of the PRL receptor and the sites where it is expressed within the brain, determination of the neurochemical mechanism of action of PRL and its effect on genomic expression in neurones, identification of the neural sites where PRL acts to stimulate maternal behaviour and related affective states, and exploration of how life experiences impact neural PRL receptor activity and actions. The next 30 years promise to reveal a myriad of basic and clinical findings regarding new roles for PRL and a greater indepth understanding of how and where PRL affects physiological and behavioural processes.

Infundibulo-tuberal syndrome: the origins of clinical neuroendocrinology in France

The birth of clinical neuroendocrinology can be dated to the year 1900, when the French neurologist Joseph Babinski (1857-1932) described a particular syndrome of adiposity and sexual infantilism in an adolescent with a craniopharyngioma expanding at the base of the brain. This condition of adipose-genital dystrophy, also known as Babinski-Fröhlich syndrome, represented the first clinical evidence that the brain controlled endocrine functions. Adipose-genital dystrophy forms part of infundibulo-tuberal syndrome, which groups the endocrine, metabolic and behavioral disturbances caused by lesions involving the upper neurohypophysis (median eminence) and the adjacent basal hypothalamus (tuber cinereum). This syndrome was originally described by the French neuropsychiatrists Henri Claude (1869-1946) and Jean Lhermitte (1877-1959) in 1917, also in a patient with a craniopharyngioma. This type of tumor involves specifically the infundibulo-tuberal region of the hypothalamus, providing a clinical model to conceptualize the separation of hypophyseal and hypothalamic functions. The French School of Neurology analyzed and reported the symptoms associated with dysfunction of the basal hypothalamus by craniopharyngiomas and other types of tumors, influencing significantly the development of clinical neuroendocrinology. Experimental lesions performed in the tuber cinereum by the French physiologists Jean Camus (1872-1924) and Gustave Roussy (1874-1948) demonstrated unmistakably the anatomical origin of infundibulo-tuberal syndrome in the basal hypothalamus. This article reviews the original findings on infundibulo-tuberal syndrome reported by the French School of Neurology in the first decades of the twentieth century and the great influence this school had on modern conceptions of hypothalamic control over endocrine functions and behavior.

60 YEARS OF NEUROENDOCRINOLOGY: MEMOIR: Geoffrey Harris and my brush with his unit

Geoffrey Harris is chiefly known for his demonstration of the control of the pituitary gland by the portal vessels coming from the hypothalamus. This does not do justice to his extraordinary contribution to biology. Harris' life's work was central in demonstrating the brain/body interactions by which animals and humans adapt to their environment, and above all the control of that most crucial and proximate of all evolutionary events - reproduction. In this brief review, I have tried to put Geoffrey Harris' work in the context of the scientific thinking at the time when he began his work, and above all, the contribution of his mentor, FHA Marshall, on whose towering shoulders Harris rose. But this is mainly my personal story, in which I have tried to show the debt that my work owed to Harris and especially to my dear friend, the late Keith Brown-Grant in Harris' team. I myself was never an endocrinologist, but over a short period in the early 1970s, under the influence of such inspirational mentors, and using purely anatomical methods, I was able to demonstrate sexual dimorphism and hormone-dependent sexual differentiation in the connections of the preoptic area, regeneration of the median eminence, the ultrastructure of apoptosis, the requirement for the suprachiasmatic nuclei in reproductive rhythms, the existence of non-rod or cone photoreceptors in the albino rat retina and, later, the expression of vasopressin by solitary (one in 600) magnocellular neurons in the polydipsic di/di Brattleboro mutant rat; this phenomenon was subsequently shown to be due to a+1 reading frameshift. I end this brief overview by mentioning some of the abiding and fascinating mysteries of the endocrine memory of the brain that arise from Harris' work on the control of the endocrines, and by pointing out how the current interest in chronobiology emphasises what a Cinderella the endocrine mechanisms have become in current brain imaging studies.

OLD AND NEW NEUROENDOCRINE MOLECULES: SOMATOSTATIN, CYSTEAMINE, PANTETHINE AND KYNURENINE

The aim of this review is to commemorate Hans Selye, endocrinologist, the most famous researchers of stress and to briefly summarize the major features of somatostatin (SST), cysteamine (CysA) and patethine (PAN) in neuroendocrinological aspect, which are closely related to his scientific work. In addition, some metabolites of kynurenine pathway (KP) were also mentioned in this paper, as new, possible target molecules in neuroendocrinology. R. Guillemin and A. V. Schally were the main pioneers of the discovery of SST in the 1970's. SST primarily is known as an inhibitor of growth hormone secretion and additionally reduces the gastric acid and pepsin release and also the gastroduodenal mucosal blood flow. These effects are very important in the pathophysiology of peptic ulcer bleeding, which is related to the CysA-evoked perforating duodenal ulcer experimental stress model in rats developed by Selye and Szabo. CysA is a naturally occurring duodenal ulcerogen, which depletes SST in the gastric mucosa and certain brain regions. Furthermore, in addition to depleting SST, CysA also causes adrenocortical necrosis, suggesting an interaction between the central/peripheral nervous system and the neuroendocrine system. The antioxidant PAN, formulated besides the CysA, has similar effects: it attenuates the levels of SST and prolactin in the cerebral cortex and hypothalamus through the accumulation of CysA within cells throughout the body. As new perspectives the KP may be involved in the modulation of neuroendrocrine processes: different agonists and antagonists of glutamate receptors regulate the hypothalamic-pituitary-adrenal axis and kynurenic acid augments the anxiolytic stress responses in neonatal chicks. The pro-inflammatory cytokine-induced and the toxic heavy oil contaminations-evoked alterations in the KP indirectly contribute to the development of neuroendocrine disorders. In summary, there have been highly important developments in neuroendocrinology since the early findings of Selye. Although there are as yet relatively few data about the potential role of kynurenines in neuroendocrinology, the results already achieved are extremely noteworthy and immensely promising.

Eugen Steinach: the first neuroendocrinologist

In 1936, Eugen Steinach and colleagues published a work that brought steroid biochemistry to the study of sexual behavior and, using synthetic androgens and estrogens, foreshadowed by an astonishing 4 decades the discovery of the central role of estrogen in the sexual behavior of male rats. We offer an English translation of that paper, accompanied by historical commentary that presents Steinach as a pioneer in reproductive neuroendocrinology. His work 1) established the interstitial cells as the main source of mammalian gonadal hormones; 2) launched the hypothesis that steroid hormones act on the brain to induce sexual behavior and that chronic gonadal transplants produce sexual reversals in physiology and behavior; 3) demonstrated the influence of sensory stimulation on testicular function; and finally 4) spearheaded the development of synthetic commercial hormones for clinical use in humans. Although its applications were controversial, Steinach's research was confirmed by many, and his concepts were applied to fields such as oncology and vascular disease. His contemporaries lauded his research, as indicated by his 7 Nobel Prize nominations. But Steinach's basic research was rarely acknowledged as the field flourished after 1950. The translation and our commentary attempt to reverse that neglect among behavioral neuroendocrinologists and clarify his central role as a founder of the neuroendocrinology of sexual behavior and reproduction.

The Central Institute for Brain Research in Amsterdam and its directors

The Central Institute for Brain Research was founded in Amsterdam in 1908 as part of an international effort to study the nervous system with multiple institutions and various disciplines. The development of research in the past hundred years at the Brain Institute has hardly been documented. We analyze the history of this institute by means of brief portraits of its directors and their main research topics. It appears that each director introduced his own branch of neuroscience into the institute. Initially, mainly comparative neuroanatomical data were collected. Following the Second World War, the multidisciplinary approach slowly developed with research programs on systems neuroscience, neuroendocrinology, and brain disorders. Every new director introduced new approaches to the study of the brain and thus played an important role in keeping brain research in the Netherlands at the international forefront where it has been ever since its foundation in 1908.

Historical and cultural aspects of the pineal gland: comparison between the theories provided by Spiritism in the 1940s and the current scientific evidence

Significance has been attached to the pineal gland in numerous different cultures and beliefs. One religion that has advanced the role of the pineal gland is Spiritism. The objective of the present study was to compile information on the pineal gland drawing on the books of Francisco Cândido Xavier written through psychography and to carry out a critical analysis of their scientific bases by comparing against evidence in the current scientific literature. A systematic search using the terms "pineal gland" and "epiphysis" was conducted of 12 works allegedly dictated by the spirit "André Luiz". All information on the pineal having potential correlation with the field of medicine and current studies was included. Specialists in the area were recruited to compile the information and draw parallels with the scientific literature. The themes related to the pineal gland were: mental health, reproductive function, endocrinology, relationship with physical activity, spiritual connection, criticism of the theory that the organ exerts no function, and description of a hormone secreted by the gland (reference alluding to melatonin, isolated 13 years later). The historical background for each theme was outlined, together with the theories present in the Spiritist books and in the relevant scientific literature. The present article provides an analysis of the knowledge the scientific community can acquire from the history of humanity and from science itself. The process of formulating hypotheses and scientific theories can benefit by drawing on the cultural aspects of civilization, taking into account so-called non-traditional reports and theories.

The eyes have it: A brief history of crustacean neuroendocrinology

To help celebrate the 50th anniversary of General and Comparative Endocrinology, the history of only a small portion of crustacean endocrinology is presented here. The field of crustacean endocrinology dates back to the decades prior to the establishment of General and Comparative Endocrinology and the first article about crustacean endocrinology published in this journal was concerned with the anatomy of neurosecretory and neurohemal structures in brachyuran crabs. This review looks at the history of neuroendocrinology in crustaceans during that time and tries to put perspective on the future of this field.

Teratology on the crossroads: historical aspects and modern approaches

Teratology is the science of congenital developmental disorders (CDDs), overt or latent defects of the organism resulting from the effect of internal and external factors on developmental processes. In this article the significance and position of present-day teratology is discussed in the context of development of this branch of science and related disciplines. The authors present an updated overview of the most important milestones and stages of the development of teratology. Based on the analysis of the historical development of theses and theories that represent a decisive contribution to this field, we present a survey of the fundamental principles of experimental and clinical teratology. The aim of observing these principles is to get insight into developmental relations and to understand mechanisms of action on the level of cell populations (elementary morphogenetic processes), tissues and organs. It is important to realize that any negative intervention into the normal course of these processes, either on genetic or non-genetic basis, inevitably leads to a sequence of subsequent changes resulting in the development of congenital developmental disorders. Despite modern approaches of molecular biology and genetics, along with top diagnostic techniques, we are still not able to identify the actual cause in more than 50% of all congenital defects. One-half of the unidentified cases are referred to as "multifactorial", a term that is rather ambiguous. It either means that some of the basic principles of teratogenesis still escape our attention, or the interpretation of some of the well known principles might be misleading. A third possibility is rather pessimistic. The development of the individual is so sophisticated and dependent on a delicate network of a multitude of factors mutually affecting each other that it is extremely prone to give rise to a plethora of spontaneous errors which are unpredictable and impossible to prevent. Nevertheless, the long and complicated history of scientific endeavour has yielded considerable present-day knowledge on causes and mechanisms of CDDs, a history whose beginnings date back to antiquity.

Laudatio for centenary of the birth of Luigi Di Bella, MD, PhD

On the centennial of the birth of Luigi Di Bella, the desire to memorialise, at least in part, his thoughts has prompted us to write this tribute, in the hope that one day his dreams may come true. Throughout his research for a treatment of cancer, he deemed it necessary to employ a complex array of substances that, by acting centripetally on neoplastic cells, could in turn be capable of affecting, either simultaneously or sequentially, the myriad of biological reactions supporting their lives. Hence, not a substance but a method (Di Bella Method, DBM). These brief hints at some aspects of Prof. Di Bella's multifaceted scientific vision are aimed not only at reasserting the truth, but also at giving a modest contribution to a novel and free direction in experimental and clinical science.

Chapter 23: history of neuroendocrinology "the spring of primitive existence"

The history of neuroendocrinology is intimately related to one of the key questions, i.e. how does the brain manage to keep us alive and let our species survive? Neuroendocrinology, part of the answer to this question, is the discipline that studies hormone production by neurons, the sensitivity of neurons to hormones, and the dynamic, bidirectional interactions between neurons and endocrine glands. These interactions do not only occur through hormones, but are partly executed by the autonomic system that is regulated by the hypothalamus and that innervates not only the endocrine glands, but all our organs. The hypothalamus acts as a central integrator for endocrine, autonomic, and higher brain functions. The history of neuroendocrinology begins in 200 AD, with Galenus, who postulated that the brain excreted a residue from animal spirits (pituita), and continues into the last century, when researchers from different disciplines tried to understand how the brain regulates the vital functions of the body. Thanks to massive recent electronic publications of English and German scientific journals from the early 20th century we were able to rediscover fascinating articles, written in Europe before World War II, which showed that some of our most recent "innovative" concepts had in fact already been thought up some 50-100 years earlier. Apparently, World War II and the migration and exile of many researchers interrupted the development of concepts in this field and made rediscovery necessary. Our chapter gives an overview of the developments, both new and newly discovered.

Governor Pio Pico, the monster of California...no more: lessons in neuroendocrinology

We hypothesize that Pio Pico, the last Mexican Governor of California, had acromegaly between at least ages 43 to 57, from 1844 to 1858, before Pierre Marie published the clinical description of acromegaly in 1886. Pico's probable growth hormone-secreting pituitary tumor likely infarcted spontaneously after 1858. The tumor infarction resulted in burnt-out acromegaly and probably restored normal pituitary function. Pearce Bailey published the first account of pituitary tumor infarction only in 1898. Pico's undiagnosed, misunderstood, profoundly acromegalic appearance was widely misinterpreted, leading to pervasive, degrading, and highly prejudicial comments. This landmark case study in neuroendocrinology provides the opportunity to re-examine elements of 19th century California and American history.

The organizational-activational hypothesis as the foundation for a unified theory of sexual differentiation of all mammalian tissues

The 1959 publication of the paper by Phoenix et al. was a major turning point in the study of sexual differentiation of the brain. That study showed that sex differences in behavior, and by extension in the brain, were permanently sexually differentiated by testosterone, a testicular secretion, during an early critical period of development. The study placed the brain together in a class with other major sexually dimorphic tissues (external genitalia and genital tracts), and proposed an integrated hormonal theory of sexual differentiation for all of these non-gonadal tissues. Since 1959, the organizational-activational theory has been amended but survives as a central concept that explains many sex differences in phenotype, in diverse tissues and at all levels of analysis from the molecular to the behavioral. In the last two decades, however, sex differences have been found that are not explained by such gonadal hormonal effects, but rather because of the primary action of genes encoded on the sex chromosomes. To integrate the classic organizational and activational effects with the more recently discovered sex chromosome effects, we propose a unified theory of sexual differentiation that applies to all mammalian tissues.

Clinical implications of the organizational and activational effects of hormones

Debate on the relative contributions of nature and nurture to an individual's gender patterns, sexual orientation and gender identity are reviewed as they appeared to this observer starting from the middle of the last century. Particular attention is given to the organization-activation theory in comparison to what might be called a theory of psychosexual neutrality at birth or rearing consistency theory. The organization-activation theory posits that the nervous system of a developing fetus responds to prenatal androgens so that, at a postnatal time, it will determine how sexual behavior is manifest. How organization-activation was or was not considered among different groups and under which circumstances it is considered is basically understood from the research and comments of different investigators and clinicians. The preponderance of evidence seems to indicate that the theory of organization-activation for the development of sexual behavior is certain for non-human mammals and almost certain for humans. This article also follows up on previous clinical critiques and recommendations and makes some new suggestions.

The Organizational Hypothesis: Reflections on the 50th anniversary of the publication of Phoenix, Goy, Gerall, and Young (1959)

The 1959 publication of "Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig" by Charles H. Phoenix, Robert W. Goy, Arnold A. Gerall, and William C. Young transformed how sex differences in mating behavior were thought to develop. Previous work provided extensive evidence that steroid hormones activated patterns of male and female sexual behavior, but only activated the behavioral patterns typical of a given sex. The 1959 paper explained this phenomenon by arguing that androgens, or their metabolites, acting at specific time(s) during development sexually dimorphically organized the tissues mediating mating behavior, which were activated by appropriate hormonal stimulation in adulthood. Thus, exposure to steroids at specific time(s) permanently altered the structure or function of the organism. The exact hormone, exact timing, exact mechanism, and exact tissues were unspecified in the article. The last two paragraphs of the discussion illustrate the investigators' unresolved views. The first proposes that the 'organization' was likely to be functional and not evident in visible structure, whereas the next paragraph argues that behavioral change implies structural change and thus structural changes are the likely consequence of steroid actions. These unresolved issues have produced extensive work in the intervening 50 years. The papers in this issue mark the 50th anniversary of this landmark paper and reflect the scope and relevance of the issues raised in the original paper and demonstrate the progress that has been made in understanding the Organizational Hypothesis and its impact on sexual differentiation.

Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig

Our "Organizing Action" paper published in 1959 put forward the concept that prenatal exposure to testosterone masculinized the behavior of genetic female guinea pigs. Specifically, we proposed that testosterone or some metabolite acted on the central nervous tissues in which patterns of sexual behavior are organized. We later went on to demonstrate similar effects in rhesus monkeys by showing that play behavior by female monkeys prenatally treated with testosterone was masculinized as well. These findings support the organizing actions of androgens as a general process of sexual differentiation.

[University, Research, Neurosciences: forty years of experience and experiments]

Closing this symposium, André Calas remembers his teachers, his past and present collaborators, his students, his teaching and research itineraries and enlarges on the problems of public policy concerning these areas in France.

[André Calas, the original path of a neuroendocrinologist]

This talk, given as an introduction to a symposium organised to honor André Calas, calls forth his personality, recalls the major events in his career and summarizes the evolution of his research.

From Leningrad to London: the saga of Kulchitsky and the legacy of the enterochromaffin cell

By the end of the 19th century, the subject of internal secretion and the consequences of its perturbations had been explored in considerable depth but with little clear understanding. Despite the anatomic delineation of the majority of the glands and tissues that comprised the gross endocrine system, the cellular basis and the interactions between the 'internal glands' and the nervous system had not been clearly delineated. Prominent early investigators in the field included Rudolf Peter Heidenhain (1834-1897), who described a novel class of clear cells (1868), Paul Langerhans (1847-1888), who identified pancreatic islets in 1869, and M.C. Ciacco (1877-1956), who coined the term 'enterochromaffin' (1906). Their contributions facilitated the description of the diffuse neuroendocrine system (DNES) by F. Feyrter (1938) which allowed for the understanding of a syncytial regulatory system that consisted of both endocrine and neural components. This rich developmental history often reveals the name of Kulchitsky, but little recognition has been given to his seminal contributions. Indeed the Russian, Nikolai Konstantinovich Kulchitsky (1856-1925), both due to his modest and unassuming nature and the tragic events of his life, was little recognized and has been relegated to a mere eponymous attribution. In reality, his life bears legacy to rich scientific contributions spanning a great teaching and scientific career at Kharkov University, to responsibilities as the Imperial Minister of Education for all of Russia. He identified the Kulchitsky cell, trained and mentored numerous professors of histopathology, was incarcerated by the Bolsheviks and worked in a soap factory to save his life. He and his family finally fled on a British battleship with the remnants of the Russian Royal family to England where he secured a position with Bayliss and Starling at University College, London (UCL). His mysterious demise in a lift-shaft accident on his 69th birthday tragically terminated a life of great service to science and teaching. He excelled as a histopathologist and was responsible for the early description of tonsillar and gut epithelial leucocytes as well as defining components of the Ascaris life cycle. At UCL, his contributions to the anatomic delineation of muscle nerve endings were highly regarded and widely admired. It is, however, his identification of the enterochromaffin cell in 1897 for which he is most remembered since this observation formed the basis for the subsequent delineation of the DNES and provided the cellular framework on which the discipline of gut neuroendocrinology would be established.