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<i>General and Comparative Endocrinology</i>is a new journal that, unlike several of its contemporaries, has quickly proved its<i>raison d'être</i>and achieved the appreciation of its readers. This book is the first supplement to the journal. It is a handsome volume containing the proceedings of the Third International Symposium on Comparative Endocrinology, which was held at Oiso, Japan, June 5-11, 1961. The individual papers, most of which are well presented and illustrated, are grouped together into chapters on the basis of their subject (chemical and immunological aspects of hormones, hormones affecting environmental adjustment, regulation of pigmentary phenomena, neuroendocrine phenomena, hormonal control of reproductive and adaptive behavior, integration of reproductive functions, and endocrine regulation during development). This, along with a panel discussion of prospectives in endocrinology, imparts some cohesion to this array of papers. The review nature of some of the contributions is also a feature attractive to the reader who
By their nature the proceedings of any conference are highly vulnerable reports, readily subject to extensive criticism. This publication is no exception. One cannot help but admire, however, the efforts of workers to relate endocrinology and behavior. As a science, endocrinology remains operationally very diffuse with many almost independent subunits or specialized interests. Despite the years of study, behavioral inquiries defy even the simplest summary statements that meet with universal acceptance. Central nervous system involvement in the regulation of endocrines is serving as one of the few unifying approaches in endocrinology. Historically, the various endocrine glands have served as subject material for largely independent and unrelated subspeciality studies. Perhaps the most commendable contributions at this conference were the rather lucid reviews of the current state of information concerning the functional ``geography'' of the hypothalamus in effecting the integrated responses of a number of the endocrine
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The ability of bacterial pathogens to influence behavior has been recognized for decades, most notably bacteria that directly invade the nervous system. However, increasing evidence is mounting that microorganisms may directly interact with elements of the host's neurophysiological system in a noninvasive manner that ultimately results in modification of host behavior. This ability of microorganisms contained within the microbiome to influence behavior through a noninfectious and possibly non-immune-mediated route may be due to their ability to produce and recognize neurochemicals that are exactly analogous in structure to those produced by the host nervous system. This form of interkingdom signaling, which is based on bidirectional neurochemical interactions between the host's neurophysiological system and the microbiome, was introduced two decades ago and has been termed microbial endocrinology [1]. Many of the neuroendocrine hormone biosynthetic pathways that are more commonly associated with eukaryotic cells are found in prokaryotic cells, and the acquisition of such neurochemical-based synthesis pathways by eukaryotic systems is believed to be due to lateral gene transfer from bacteria. Approaching the microbiome from a microbial endocrinology-based vantage point may provide an understanding of the specific pathways by which microorganisms may influence behavior and thereby lead to new approaches to the treatment of specific mental illness based on modulation of the microbiome-gut-brain axis.
Although genetics determines endocrine phenotypes, it cannot fully explain the great variability and reversibility of the system in response to environmental changes. Evidence now suggests that epigenetics, i.e. heritable but reversible changes in gene function without changes in nucleotide sequence, links genetics and environment in shaping endocrine function. Epigenetic mechanisms, including DNA methylation, histone modification, and microRNA, partition the genome into active and inactive domains based on endogenous and exogenous environmental changes and developmental stages, creating phenotype plasticity that can explain interindividual and population endocrine variability. We will review the current understanding of epigenetics in endocrinology, specifically, the regulation by epigenetics of the three levels of hormone action (synthesis and release, circulating and target tissue levels, and target-organ responsiveness) and the epigenetic action of endocrine disruptors. We will also discuss the impacts of hormones on epigenetics. We propose a three-dimensional model (genetics, environment, and developmental stage) to explain the phenomena related to progressive changes in endocrine functions with age, the early origin of endocrine disorders, phenotype discordance between monozygotic twins, rapid shifts in disease patterns among populations experiencing major lifestyle changes such as immigration, and the many endocrine disruptions in contemporary life. We emphasize that the key for understanding epigenetics in endocrinology is the identification, through advanced high-throughput screening technologies, of plasticity genes or loci that respond directly to a specific environmental stimulus. Investigations to determine whether epigenetic changes induced by today's lifestyles or environmental 'exposures' can be inherited and are reversible should open doors for applying epigenetics to the prevention and treatment of endocrine disorders.
Hans Selye's single author short letter to Nature (1936, 138(3479):32) inspired a huge and still growing wave of medical research. His experiments with rats led to recognition of the "general adaptation syndrome", later renamed by Selye "stress response": the triad of enlarged adrenal glands, lymph node and thymic atrophy, and gastric erosions/ulcers. Because of the major role of glucocorticoids (named by Selye), he performed extensive structure-activity studies in the 1930s-1940s, resulting in the first rational classification of steroid hormones, e.g. corticoids, testoids/androgens, and folliculoids/estrogens. During those years, he recognized the respective anti- and pro-inflammatory actions of gluco- and mineralocorticoids in animal models, several years before demonstration of anti-rheumatic actions of cortisone and adrenocorticotrophic hormones in patients. Nevertheless, Selye did not receive a Nobel Prize, which was awarded in 1950 to the clinician Hench and the two chemists who isolated and synthesized some of the glucocorticoids. Nonetheless, Selye was internationally recognized as a world authority in endocrinology, steroid chemistry, experimental surgery, and pathology. He wrote over 1500 original and review articles, singly authored 32 books, and trained 40 PhD students, one of whom (Roger Guillemin) won a Nobel Prize for isolating the hypothalamic releasing factors/hormones. Here, we consider the main implications of his first article launching the biological stress concept and the key ideas and problems that occupied him. Selye considered "Stress in heath and disease is medically, sociologically, and philosophically the most meaningful subject for humanity that I can think of".
Trust is among the most important factors in human life, as it pervades almost all domains of society. Although behavioral research has revealed a number of insights into the nature of trust, as well as its antecedents and consequences, an increasing number of scholars have begun to investigate the topic from a biological perspective to gain a deeper understanding. These biological investigations into trust have been carried out on three levels of analysis: genes, endocrinology, and the brain. Based on these three levels, we present a review of the literature on the biology of trust. Moreover, we integrate our findings into a conceptual framework which unifies the three levels of analysis, and we also link the biological levels to trust behavior. The results show that trust behavior is at least moderately genetically predetermined. Moreover, trust behavior is associated with specific hormones, in particular oxytocin, as well as specific brain structures, which are located in the basal ganglia, limbic system, and the frontal cortex. Based on these results, we discuss both methodological and thematic implications.
: By definition, an adrenal incidentaloma is an asymptomatic adrenal mass detected on imaging not performed for suspected adrenal disease. In most cases, adrenal incidentalomas are nonfunctioning adrenocortical adenomas, but may also represent conditions requiring therapeutic intervention (e.g. adrenocortical carcinoma, pheochromocytoma, hormone-producing adenoma or metastasis). The purpose of this guideline is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with adrenal incidentalomas based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions crucial for the management of adrenal incidentaloma patients, addressing these four with systematic literature searches: (A) How to assess risk of malignancy?; (B) How to define and manage low-level autonomous cortisol secretion, formerly called 'subclinical' Cushing's syndrome?; (C) Who should have surgical treatment and how should it be performed?; (D) What follow-up is indicated if the adrenal incidentaloma is not surgically removed? SELECTED RECOMMENDATIONS: (i) At the time of initial detection of an adrenal mass establishing whether the mass is benign or malignant is an important aim to avoid cumbersome and expensive follow-up imaging in those with benign disease. (ii) To exclude cortisol excess, a 1mg overnight dexamethasone suppression test should be performed (applying a cut-off value of serum cortisol ≤50nmol/L (1.8µg/dL)). (iii) For patients without clinical signs of overt Cushing's syndrome but serum cortisol levels post 1mg dexamethasone >138nmol/L (>5µg/dL), we propose the term 'autonomous cortisol secretion'. (iv) All patients with '(possible) autonomous cortisol' secretion should be screened for hypertension and type 2 diabetes mellitus, to ensure these are appropriately treated. (v) Surgical treatment should be considered in an individualized approach in patients with 'autonomous cortisol secretion' who also have comorbidities that are potentially related to cortisol excess. (vi) In principle, the appropriateness of surgical intervention should be guided by the likelihood of malignancy, the presence and degree of hormone excess, age, general health and patient preference. (vii) Surgery is not usually indicated in patients with an asymptomatic, nonfunctioning unilateral adrenal mass and obvious benign features on imaging studies. We provide guidance on which surgical approach should be considered for adrenal masses with radiological findings suspicious of malignancy. Furthermore, we offer recommendations for the follow-up of patients with adrenal incidentaloma who do not undergo adrenal surgery, for those with bilateral incidentalomas, for patients with extra-adrenal malignancy and adrenal masses and for young and elderly patients with adrenal incidentalomas.
Perturbations of the composition and function of the gut microbiota have been associated with metabolic disorders including obesity, insulin resistance and type 2 diabetes. Studies on mice have demonstrated several underlying mechanisms including host signalling through bacterial lipopolysaccharides derived from the outer membranes of Gram-negative bacteria, bacterial fermentation of dietary fibres to short-chain fatty acids and bacterial modulation of bile acids. On top of this, an increased permeability of the intestinal epithelium may lead to increased absorption of macromolecules from the intestinal content resulting in systemic immune responses, low-grade inflammation and altered signalling pathways influencing lipid and glucose metabolism. While mechanistic studies on mice collectively support a causal role of the gut microbiota in metabolic diseases, the majority of studies in humans are correlative of nature and thus hinder causal inferences. Importantly, several factors known to influence the risk of type 2 diabetes, e.g. diet and age, have also been linked to alterations in the gut microbiota complicating the interpretation of correlative studies. However, based upon the available evidence, it is hypothesised that the gut microbiota may mediate or modulate the influence of lifestyle factors triggering development of type 2 diabetes. Thus, the aim of this review is to critically discuss the potential role of the gut microbiota in the pathophysiology and pathogenesis of type 2 diabetes.
We are in the midst of what some have called a "mobile health revolution". Medical applications ("apps") for mobile phones are proliferating in the marketplace and clinicians are likely encountering patients with questions about the medical value of these apps. We conducted a review of medical apps focused on endocrine disease. We found a higher percentage of relevant apps in our searches of the iPhone app store compared with the Android marketplace. For our diabetes search in the iPhone store, the majority of apps (33%) focused on health tracking (blood sugars, insulin doses, carbohydrates), requiring manual entry of health data. Only two apps directly inputted blood sugars from glucometers attached to the mobile phone. The remainder of diabetes apps were teaching/training apps (22%), food reference databases (8%), social blogs/forums (5%), and physician directed apps (8%). We found a number of insulin dose calculator apps which technically meet criteria for being a medically regulated mobile application, but did not find evidence for FDA-approval despite their availability to consumers. Far fewer apps were focused on other endocrine disease and included medical reference for the field of endocrinology, access to endocrine journals, height predictors, medication trackers, and fertility apps. Although mobile health apps have great potential for improving chronic disease care, they face a number of challenges including lack of evidence of clinical effectiveness, lack of integration with the health care delivery system, the need for formal evaluation and review and organized searching for health apps, and potential threats to safety and privacy.
Endocrinology of Adipose Tissue -An Update ures and of specifi c drugs that may be able to restore the dysregulated endocrine system of adipose tissue. It was hoped that through prevention and intervention the deleterious sequelae of obesity and, in particular, of the visceral accumulation of body fat, might be avoided. Five years later, more than one hundred adipose tissue secretion products have been described including fatty acids, prostaglandins, and steroids, as well as complex proteins ( Fig. Some of these factors primarily have local auto-or paracrine effects in adipose tissue, while others are released into the circulation and exert specifi c effects at target organs or systemic effects. In this review, we present an overview of the endocrine functions of adipose tissue with special focus on fi ndings obtained within the past 5 years.
The epithelial ovarian carcinomas, which make up more than 85% of human ovarian cancer, arise in the ovarian surface epithelium (OSE). The etiology and early events in the progression of these carcinomas are among the least understood of all major human malignancies because there are no appropriate animal models, and because methods to culture OSE have become available only recently. The objective of this article is to review the cellular and molecular mechanisms that underlie the control of normal and neoplastic OSE cell growth, differentiation, and expression of indicators of neoplastic progression. We begin with a brief discussion of the development of OSE, from embryonic to the adult. The pathological and genetic changes of OSE during neoplastic progression are next summarized. The histological characteristics of OSE cells in culture are also described. Finally, the potential involvement of hormones, growth factors, and cytokines is discussed in terms of their contribution to our understanding of the physiology of normal OSE and ovarian cancer development.
Adrenocortical carcinoma (ACC) is a rare and in most cases steroid hormone-producing tumor with variable prognosis. The purpose of these guidelines is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with ACC based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions, which we judged as particularly important for the management of ACC patients and performed systematic literature searches: (A) What is needed to diagnose an ACC by histopathology? (B) Which are the best prognostic markers in ACC? (C) Is adjuvant therapy able to prevent recurrent disease or reduce mortality after radical resection? (D) What is the best treatment option for macroscopically incompletely resected, recurrent or metastatic disease? Other relevant questions were discussed within the group. Selected Recommendations: (i) We recommend that all patients with suspected and proven ACC are discussed in a multidisciplinary expert team meeting. (ii) We recommend that every patient with (suspected) ACC should undergo careful clinical assessment, detailed endocrine work-up to identify autonomous hormone excess and adrenal-focused imaging. (iii) We recommend that adrenal surgery for (suspected) ACC should be performed only by surgeons experienced in adrenal and oncological surgery aiming at a complete en bloc resection (including resection of oligo-metastatic disease). (iv) We suggest that all suspected ACC should be reviewed by an expert adrenal pathologist using the Weiss score and providing Ki67 index. (v) We suggest adjuvant mitotane treatment in patients after radical surgery that have a perceived high risk of recurrence (ENSAT stage III, or R1 resection, or Ki67 >10%). (vi) For advanced ACC not amenable to complete surgical resection, local therapeutic measures (e.g. radiation therapy, radiofrequency ablation, chemoembolization) are of particular value. However, we suggest against the routine use of adrenal surgery in case of widespread metastatic disease. In these patients, we recommend either mitotane monotherapy or mitotane, etoposide, doxorubicin and cisplatin depending on prognostic parameters. In selected patients with a good response, surgery may be subsequently considered. (vii) In patients with recurrent disease and a disease-free interval of at least 12 months, in whom a complete resection/ablation seems feasible, we recommend surgery or alternatively other local therapies. Furthermore, we offer detailed recommendations about the management of mitotane treatment and other supportive therapies. Finally, we suggest directions for future research.
BACKGROUND: Cushing's syndrome (CS) is characterized by excessive exposure to cortisol, and is associated with both metabolic and behavioral abnormalities. Symptoms improve substantially after biochemical cure, but may persist during long-term remission. The causes for persistent morbidity are probably multi-factorial, including a profound effect of cortisol excess on the brain, a major target area for glucocorticoids. OBJECTIVE: To review publications evaluating brain characteristics in patients with CS using magnetic resonance imaging (MRI). METHODS: Systematic review of literature published in PubMed, Embase, Web of Knowledge, and Cochrane databases. RESULTS: Nineteen studies using MRI in patients with CS were selected, including studies in patients with active disease, patients in long-term remission, and longitudinal studies, covering a total of 339 unique patients. Patients with active disease showed smaller hippocampal volumes, enlarged ventricles, and cerebral atrophy as well as alterations in neurochemical concentrations and functional activity. After abrogation of cortisol excess, the reversibility of structural and neurochemical alterations was incomplete after long-term remission. MRI findings were related to clinical characteristics (i.e., cortisol levels, duration of exposure to hypercortisolism, current age, age at diagnosis, and triglyceride levels) and behavioral outcome (i.e., cognitive and emotional functioning, mood, and quality of life). CONCLUSION: Patients with active CS demonstrate brain abnormalities, which only partly recover after biochemical cure, because these still occur even after long-term remission. CS might be considered as a human model of nature that provides a keyhole perspective of the neurotoxic effects of exogenous glucocorticoids on the brain.
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The new field of microbiome research studies the microbes within multicellular hosts and the many effects of these microbes on the host's health and well-being. We now know that microbes influence metabolism, immunity and even behavior. Essential questions, which are just starting to be answered, are what are the mechanisms by which these bacteria affect specific host characteristics. One important but understudied mechanism appears to involve hormones. Although the precise pathways of microbiota-hormonal signaling have not yet been deciphered, specific changes in hormone levels correlate with the presence of the gut microbiota. The microbiota produces and secretes hormones, responds to host hormones and regulates expression levels of host hormones. Here, we summarize the links between the endocrine system and the gut microbiota. We categorize these interactions by the different functions of the hormones, including those affecting behavior, sexual attraction, appetite and metabolism, gender and immunity. Future research in this area will reveal additional connections, and elucidate the pathways and consequences of bacterial interactions with the host endocrine system.
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