{"title":"Physiology and Pathophysiology of Water Homeostasis.","authors":"Helbert Rondon-Berrios, Tomas Berl","doi":"10.1159/000493233","DOIUrl":"https://doi.org/10.1159/000493233","url":null,"abstract":"<p><p>In the evolutionary process, the successful adaptation of living organisms initially to an aqueous and thereafter to an arid terrestrial environment posed radically different challenges to the maintenance of water balance. Whereas the former required defense against water excess, the latter called for water conservation. To meet such challenges, the mammalian nephron evolved mechanisms for increasing both water excretion by diluting and water conservation by concentrating the urine. This chapter reviews the process whereby the osmosensors control thirst and the secretion of the antidiuretic hormone (vasopressin) to allow for either urinary dilution or concentration and thereby delicately maintain tonicity of body fluids within a very narrow range. Central to this process is the now well-defined cellular pathway whereby vasopressin renders the collecting duct, water permeable. Disorders of vasopressin secretion and action result in disturbances of body fluids tonicity, which are clinically recognized as abnormalities in reduced plasma sodium concentration or hyponatremia.</p>","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"52 ","pages":"8-23"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000493233","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37677019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Adverse Consequences of Overly-Rapid Correction of Hyponatremia.","authors":"Richard H Sterns","doi":"10.1159/000493243","DOIUrl":"https://doi.org/10.1159/000493243","url":null,"abstract":"<p><p>A time-dependent loss of cell solute protects against lethal cerebral edema in hyponatremia. This adaptation, which makes survival possible when the serum sodium concentration is extremely low, also makes the brain vulnerable to injury if chronic (>48 hours) hyponatremia is corrected more rapidly than lost brain solutes can be recovered. Rapid correction of chronic hyponatremia results in programmed cell death of astrocytes and oligodendrocytes and presents clinically with a delayed onset of neurological findings, known as the osmotic demyelination syndrome. This iatrogenic complication can be avoided by limiting correction of hyponatremia to <8 mEq/L per day.</p>","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"52 ","pages":"130-142"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000493243","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37677022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Endocrinology of Hirsutism: From Androgens to Androgen Excess Disorders.","authors":"B. Yilmaz, B. Yıldız","doi":"10.1159/000494907","DOIUrl":"https://doi.org/10.1159/000494907","url":null,"abstract":"Unwanted sexual hair growth has a considerable negative impact on a woman's self-esteem and quality of life. Excessive growth of terminal hair in women in a man-like pattern is defined as hirsutism and affects up to 1 in 7 women. Androgens secreted by the ovary and adrenal are the main regulator of physiological and pathological alterations of skin hair. Hirsutism is the result of the interaction between circulating serum androgens and hair follicles. Hirsutism is the most commonly used clinical diagnostic criterion of hyperandrogenism and majority of hirsutism cases are due to androgen excess. Over 80% of women with hirsutism will have polycystic ovary syndrome, about 10% will have idiopathic hirsutism, and the remaining will have rare disorders including non-classical congenital adrenal hyperplasia, hyperandrogenism with insulin resistance and acanthosis nigricans, and androgen-secreting neoplasms. Cushing's syndrome, acromegaly, thyroid dysfunction and hyperprolactinemia might be associated with hirsutism as well as the use of androgens, anabolic steroids and valproate. This paper provides an overview of the principal endocrinological aspects of hirsutism including the role of androgens in excessive hair growth and associated androgen excess disorders. Clinical evaluation and management of hirsutism are also discussed.","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"53 1","pages":"108-119"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000494907","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65285302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Androgens in Cushing's Syndrome.","authors":"G. Arnaldi, M. Martino","doi":"10.1159/000494904","DOIUrl":"https://doi.org/10.1159/000494904","url":null,"abstract":"Although polycystic ovary syndrome (PCOS) is the most common androgen excess disorder, screening for Cushing's Syndrome (CS) should be considered in women with PCOS phenotype, particularly if they are also affected by other disturbances that increase their pretest probability (e.g., osteoporosis/bone fractures). Approximately 70-80% of women with CS present menstrual abnormalities, and PCOS findings are found in 46% of these patients. Diagnostic efforts should strengthen if the clinical picture is severe or of rapid onset in order to ensure the earliest and most appropriate treatment. If the diagnosis of CS is challenging, its differentiation from PCOS is not outdone: isolated PCOS may be associated to hypothalamic-pituitary-adrenal axis disruption, leading to false-positive results in screening tests. Because of this overlap, the diagnosis of CS is initially missed or delayed. Diagnostic utility of serum androgen assessment is controversial, but the widespread use of high-performance liquid chromatography and gas chromatography-mass spectrometry for urinary steroid profiling is showing promising results. According to the role of adrenocorticotropic hormone (ACTH) in adrenal androgen secretion, it is not surprising that the levels of dehydroepiandrosterone, dehydroepiandrosterone-sulfate, and androstenedione (A4) are generally elevated or in the upper normal range in patients with ACTH-dependent CS. Conversely, adrenal androgens are generally low in patients with cortisol-secreting adrenocortical adenoma. However, androgen-secreting adrenal tumors (adenoma and carcinoma) can be also associated with severe hyperandrogenism. Regression of hypercortisolism after treatment causes disappearance of hyperandrogenism. However, signs of androgen excess may be detectable in well-controlled CS as a result of ACTH compensatory response to certain adrenal steroidogenesis inhibitors.","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"53 1","pages":"77-91"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000494904","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65285159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Asymptomatic Primary Hyperparathyroidism.","authors":"Bart L Clarke","doi":"10.1159/000491035","DOIUrl":"https://doi.org/10.1159/000491035","url":null,"abstract":"<p><p>Asymptomatic primary hyperparathyroidism has become the most common presentation of primary hyperparathyroidism in Europe and North America, and an increasingly common presentation in other parts of the world. As many as 25% of asymptomatic patients may develop indications for parathyroidectomy when followed long-term for up to 15 years. Patients who remain asymptomatic should be monitored for the development of complications that justify surgery. Patients who become symptomatic should be referred for surgery. Surgery may improve quality of life even in patients who remain asymptomatic.</p>","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"51 ","pages":"13-22"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000491035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36863659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Diamanti-Kandarakis, Olga Pappalou, Eleni A. Kandaraki
{"title":"The Role of Androgen Excess on Insulin Sensitivity in Women.","authors":"E. Diamanti-Kandarakis, Olga Pappalou, Eleni A. Kandaraki","doi":"10.1159/000494902","DOIUrl":"https://doi.org/10.1159/000494902","url":null,"abstract":"Sex steroids, except for their primary reproductive role, exert key effects on metabolic target tissues. Androgen receptors have been detected in various tissues, participating in both central and peripheral regulation of metabolism and insulin action. The physiological role of androgens in regulating multiple aspects of female insulin signaling and energy metabolism becomes evident early in utero, thus programming how insulin-targeted tissues will behave in later life. Across lifespan, distinct effects of androgens in all insulin-targeted tissues are controlled by their circulating serum levels, within a narrow window, outside of which disturbances in metabolism are observed. Thus, androgen excess in women, as documented in those with polycystic ovary syndrome, can adversely affect insulin sensitivity, promoting visceral adiposity, adipose tissue dysfunction, and, ultimately, insulin resistance.","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"53 1","pages":"50-64"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000494902","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65285039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Androgen Excess in Women: Proteomic and Metabolomic Approaches.","authors":"M. Insenser, H. Escobar-Morreale","doi":"10.1159/000494910","DOIUrl":"https://doi.org/10.1159/000494910","url":null,"abstract":"Most research efforts addressing the pathophysiology of polycystic ovary syndrome (PCOS) applied targeted approaches focusing on specific genes and/or proteins that were selected on the basis of previous knowledge about their putative roles in metabolic and signalling pathways. On the contrary, the use of nontargeted approaches is not constricted by previous knowledge on the issue and offers the potential advantage of revealing novel associations with unexpected molecules that might lead to new mechanistic explanations for the etiology and the pathophysiology of PCOS. To date, several \"omics\" approaches have been applied to create a holistic picture complementing the information generated by genetic studies. Proteomics and metabolomics have the potential advantage over genomics of integrating genetic and epigenetic influences, thereby facilitating interpretation of the molecular mechanisms and pathways involved in the pathogenesis of PCOS. This chapter summarizes recent advances provided by proteomic and metabolomic studies addressing PCOS and aims to offer a critical yet balanced review of the studies published to date.","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"53 1","pages":"162-176"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000494910","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65285497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Etiology and Epidemiology of Hyponatremia.","authors":"Volker Burst","doi":"10.1159/000493234","DOIUrl":"https://doi.org/10.1159/000493234","url":null,"abstract":"Hyponatremia is a frequently encountered clinical finding, and by far the most common disorder of electrolyte and water homeostasis throughout the world. Given the complex pathophysiology of hyponatremia as well as its clinical implications, which range from apparently asymptomatic presentations to life-threatening conditions, a comprehensive understanding of its possible causes and of the frequencies of occurrence of the various types of hyponatremia in distinct clinical settings is essential for successful disease management. In this chapter, the diverse etiologies of hyponatremia are summarized, explained, and classified according to the patients' extracellular volume status. An in-depth review of the existing literature on epidemiologic data on incidence and prevalence of hyponatremia is provided covering the general population as well as the patient groups with community-acquired and hospital-acquired hyponatremia. Selected clinical scenarios that are described in detail are: hyponatremia in the geriatric population, in the emergency department, in the postoperative state, and in the intensive care setting. Distinct diseases and circumstances that are often associated with hyponatremia are reviewed briefly, while a more detailed discussion is covered in later chapters.","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"52 ","pages":"24-35"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000493234","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37677228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Clinical Presentation of Hypoparathyroidism.","authors":"Francesca Giusti, Maria Luisa Brandi","doi":"10.1159/000491044","DOIUrl":"https://doi.org/10.1159/000491044","url":null,"abstract":"<p><p>Parathyroid hormone (PTH) is one of the major hormones that regulates serum calcium. Hypoparathyroidism occurs when PTH secretion is insufficient. The main symptoms of hypoparathyroidism are the result of low blood calcium levels, hypocalcemia, which interferes with normal muscle contraction and nerve conduction. As a result, people with hypoparathyroidism can experience paresthesia, an unpleasant tingling sensation around the mouth and in the hands and feet, as well as muscle cramps and severe spasms known as \"tetany\" that affect the hands and feet. Many also report a number of other subjective symptoms. Hypocalcemia can be the cause of medical emergencies, for example seizures, severe irregularities in the normal heart beat, as well as laryngospasm, stridor, bronchospasm, and wheezing.</p>","PeriodicalId":50428,"journal":{"name":"Frontiers of Hormone Research","volume":"51 ","pages":"139-146"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1159/000491044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36863657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}