History of Adrenal Research: From Ancient Anatomy to Contemporary Molecular Biology.

The adrenal is a small, anatomically unimposing structure that escaped scientific notice until 1564 and whose existence was doubted by many until the 18th century. Adrenal functions were inferred from the adrenal insufficiency syndrome described by Addison and from the obesity and virilization that accompanied many adrenal malignancies, but early physiologists sometimes confused the roles of the cortex and medulla. Medullary epinephrine was the first hormone to be isolated (in 1901), and numerous cortical steroids were isolated between 1930 and 1949. The treatment of arthritis, Addison's disease, and congenital adrenal hyperplasia (CAH) with cortisone in the 1950s revolutionized clinical endocrinology and steroid research. Cases of CAH had been reported in the 19th century, but a defect in 21-hydroxylation in CAH was not identified until 1957. Other forms of CAH, including deficiencies of 3ß-hydroxysteroid dehydrogenase, 11ß-hydroxylase, and 17α-hydroxylase were defined hormonally in the 1960s. Cytochrome P450 enzymes were described in 1962-1964, and steroid 21-hydroxylation was the first biosynthetic activity associated with a P450. Understanding of the genetic and biochemical bases of these disorders advanced rapidly from 1984 to 2004. The cloning of genes for steroidogenic enzymes and related factors revealed many mutations causing known diseases and facilitated the discovery of new disorders. Genetics and cell biology have replaced steroid chemistry as the key disciplines for understanding and teaching steroidogenesis and its disorders.

A Brief History of the Pediatric Endocrine Society (PES).

The Pediatric Endocrine Society (PES) was initially established in 1972 as the Lawson Wilkins Pediatric Endocrine Society (LWPES), by some of Wilkins' former fellows. As the society grew from its 37 founding members and Dr. Wilkins' influence faded, the name of the society was changed in 2010 and now counts about 1,500 members, mostly from the US and Canada. Pediatric endocrine training programs headed by (LW)PES members have welcomed fellows from throughout the world, many of whom have gone on to leadership positions in their home countries. Starting in 1981, the (LW)PES has collaborated with pediatric endocrine societies around the world in quadrennial meetings, fostering collaborations, transfer of ideas, devising joint practice guidelines, and enjoying one another's fellowship and counsel. The PES presently has committees and special interest groups concerned with all aspects of pediatric endocrinology, assuring that our clinical and academic resources reflect both breadth and depth. To celebrate our 50th anniversary, selected members have written the historical manuscripts featured in this special issue of Hormone Research in Pediatrics. These historical reviews delve into the origins of our specialty, sometimes deep into antiquity, provide useful background information, and illustrate the kinds of intellectual struggles that have led to the development of contemporary pediatric endocrinology, worldwide.

A Brief History of Congenital Adrenal Hyperplasia.

The adrenal has played a major role in the history of pediatric endocrinology. Cases of congenital adrenal hyperplasia (CAH) were reported in the 19th century, leading to the understanding that the adrenal influenced sexual phenotypes as well as being mysteriously required for survival. Numerous adrenal steroids were isolated in the early 20th century, and bioassays eventually distinguished glucocorticoids, mineralocorticoids, and androgens. Treatment of CAH with cortisone in 1950 by Wilkins and by Bartter and Albright revolutionized clinical endocrinology and launched a productive era of pediatric adrenal research. Through careful clinical studies, Wilkins established the contemporary approach to treating CAH. Alfred Bongiovanni identified defective 21-hydroxylation in CAH in 1957, followed by deficiencies of 3ß-hydroxysteroid dehydrogenase and 11ß-hydroxylase. P450 enzymes were described in 1962-1964, and 21-hydroxylation was the first activity ascribed to a P450. Accurate assays for 17OH-progesterone in newborns and in response to ACTH permitted the diagnosis of CAH in children and families. Application of the techniques of molecular genetics elucidated genetic and biochemical bases of these disorders from 1984 to 2004. Pediatric endocrinologists played central roles in identifying the genes responsible for both common and rare forms of congenital adrenal hyperplasia and determining their most appropriate treatments.

Rickets, Vitamin D, and Ca/P Metabolism.

Rickets was a major public health problem dating from Roman times, and medical descriptions of rickets date from the 17th century. Sniadecki first advocated treatment by exposure to sunshine in 1822; contemporaneously, several British physicians advocated use of cod liver oil. Both approaches were successful. Work in 1924 showed that exposure to UV light endowed fats and other foods with antirachitic properties. Vitamins D2 and D3, the antirachitic agent in cod liver oil, were, respectively, produced by UV radiation of ergosterol and 7-dehydrocholesterol. Calcitriol (1,25[OH]2D3) was identified as the biologically active form of vitamin D in the early 1970s. The vitamin D 25-hydroxylase, 24-hydroxylase, and 1α-hydroxylase were cloned in the 1990s and their genetic defects were soon delineated. The vitamin D receptor was also cloned and its mutations identified in vitamin D-resistant rickets. Work with parathyroid hormone (PTH) began much later, as the parathyroids were not identified until the late 19th century. In 1925, James B. Collip (of insulin fame) identified PTH by its ability to correct tetany in parathyroidectomized dogs, but only in the 1970s was it clear that only a small fragment of PTH conveyed its activity. Congenital hypoparathyroidism with immune defects was described in 1968, eventually linked to microdeletions in chromosome 22q11.2. X-linked hypophosphatemic rickets was reported in 1957, and genetic linkage analysis identified the causative PHEX gene in 1997. Autosomal dominant hypophosphatemic rickets similarly led to the discovery of FGF23, a phosphate-wasting humoral factor made in bone, in 2000, revolutionizing our understanding of phosphorus metabolism.

Congenital Adrenal Hyperplasia-Current Insights in Pathophysiology, Diagnostics, and Management.

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders affecting cortisol biosynthesis. Reduced activity of an enzyme required for cortisol production leads to chronic overstimulation of the adrenal cortex and accumulation of precursors proximal to the blocked enzymatic step. The most common form of CAH is caused by steroid 21-hydroxylase deficiency due to mutations in CYP21A2. Since the last publication summarizing CAH in Endocrine Reviews in 2000, there have been numerous new developments. These include more detailed understanding of steroidogenic pathways, refinements in neonatal screening, improved diagnostic measurements utilizing chromatography and mass spectrometry coupled with steroid profiling, and improved genotyping methods. Clinical trials of alternative medications and modes of delivery have been recently completed or are under way. Genetic and cell-based treatments are being explored. A large body of data concerning long-term outcomes in patients affected by CAH, including psychosexual well-being, has been enhanced by the establishment of disease registries. This review provides the reader with current insights in CAH with special attention to these new developments.

Steroidogenic electron-transfer factors and their diseases.

Most steroidogenesis disorders are caused by mutations in genes encoding the steroidogenic enzymes, but work in the past 20 years has identified related disorders caused by mutations in the genes encoding the cofactors that transport electrons from NADPH to P450 enzymes. Most P450s are microsomal and require electron donation by P450 oxidoreductase (POR); by contrast, mitochondrial P450s require electron donation via ferredoxin reductase (FdxR) and ferredoxin (Fdx). POR deficiency is the most common and best-described of these new forms of congenital adrenal hyperplasia. Severe POR deficiency is characterized by the Antley-Bixler skeletal malformation syndrome and genital ambiguity in both sexes, and hence is easily recognized, but mild forms may present only with infertility and subtle disorders of steroidogenesis. The common POR polymorphism A503V reduces catalysis by P450c17 (17-hydroxylase/17,20-lyase) and the principal drugmetabolizing P450 enzymes. The 17,20-lyase activity of P450c17 requires the allosteric action of cytochrome b5, which promotes interaction of P450c17 with POR, with consequent electron transfer. Rare b5 mutations are one of several causes of 17,20-lyase deficiency. In addition to their roles with steroidogenic mitochondrial P450s, Fdx and FdxR participate in the synthesis of iron-sulfur clusters used by many enzymes. Disruptions in the assembly of Fe-S clusters is associated with Friedreich ataxia and Parkinson disease. Recent work has identified mutations in FdxR in patients with neuropathic hearing loss and visual impairment, somewhat resembling the global neurologic disorders seen with mitochondrial diseases. Impaired steroidogenesis is to be expected in such individuals, but this has not yet been studied.

Considering Sex as a Biological Variable in Basic and Clinical Studies: An Endocrine Society Scientific Statement.

In May 2014, the National Institutes of Health (NIH) stated its intent to "require applicants to consider sex as a biological variable (SABV) in the design and analysis of NIH-funded research involving animals and cells." Since then, proposed research plans that include animals routinely state that both sexes/genders will be used; however, in many instances, researchers and reviewers are at a loss about the issue of sex differences. Moreover, the terms sex and gender are used interchangeably by many researchers, further complicating the issue. In addition, the sex or gender of the researcher might influence study outcomes, especially those concerning behavioral studies, in both animals and humans. The act of observation may change the outcome (the "observer effect") and any experimental manipulation, no matter how well-controlled, is subject to it. This is nowhere more applicable than in physiology and behavior. The sex of established cultured cell lines is another issue, in addition to aneuploidy; chromosomal numbers can change as cells are passaged. Additionally, culture medium contains steroids, growth hormone, and insulin that might influence expression of various genes. These issues often are not taken into account, determined, or even considered. Issues pertaining to the "sex" of cultured cells are beyond the scope of this Statement. However, we will discuss the factors that influence sex and gender in both basic research (that using animal models) and clinical research (that involving human subjects), as well as in some areas of science where sex differences are routinely studied. Sex differences in baseline physiology and associated mechanisms form the foundation for understanding sex differences in diseases pathology, treatments, and outcomes. The purpose of this Statement is to highlight lessons learned, caveats, and what to consider when evaluating data pertaining to sex differences, using 3 areas of research as examples; it is not intended to serve as a guideline for research design.

A Novel Mitochondrial Complex of Aldosterone Synthase, Steroidogenic Acute Regulatory Protein, and Tom22 Synthesizes Aldosterone in the Rat Heart.

Aldosterone, which regulates renal salt retention, is synthesized in adrenocortical mitochondria in response to angiotensin II. Excess aldosterone causes myocardial injury and heart failure, but potential intracardiac aldosterone synthesis has been controversial. We hypothesized that the stressed heart might produce aldosterone. We used blue native gel electrophoresis, immunoblotting, protein crosslinking, coimmunoprecipitations, and mass spectrometry to assess rat cardiac aldosterone synthesis. Chronic infusion of angiotensin II increased circulating corticosterone levels 350-fold and induced cardiac fibrosis. Angiotensin II doubled and telmisartan inhibited aldosterone synthesis by heart mitochondria and cardiac production of aldosterone synthase (P450c11AS). Heart aldosterone synthesis required P450c11AS, Tom22 (a mitochondrial translocase receptor), and the intramitochondrial form of the steroidogenic acute regulatory protein (StAR); protein crosslinking and coimmunoprecipitation studies showed that these three proteins form a 110-kDa complex. In steroidogenic cells, extramitochondrial (37-kDa) StAR promotes cholesterol movement from the outer to inner mitochondrial membrane where cholesterol side-chain cleavage enzyme (P450scc) converts cholesterol to pregnenolone, thus initiating steroidogenesis, but no function has previously been ascribed to intramitochondrial (30-kDa) StAR; our data indicate that intramitochondrial 30-kDa StAR is required for aldosterone synthesis in the heart, forming a trimolecular complex with Tom22 and P450c11AS. This is the first activity ascribed to intramitochondrial StAR, but how this promotes P450c11AS activity is unclear. The stressed heart did not express P450scc, suggesting that circulating corticosterone (rather than intracellular cholesterol) is the substrate for cardiac aldosterone synthesis. Thus, the stressed heart produced aldosterone using a previously undescribed intramitochondrial mechanism that involves P450c11AS, Tom22, and 30-kDa StAR. SIGNIFICANCE STATEMENT: Prior studies of potential cardiac aldosterone synthesis have been inconsistent. This study shows that the stressed rat heart produces aldosterone by a novel mechanism involving aldosterone synthase, Tom22, and intramitochondrial steroidogenic acute regulatory protein (StAR) apparently using circulating corticosterone as substrate. This study establishes that the stressed rat heart produces aldosterone and for the first time identifies a biological role for intramitochondrial 30-kDa StAR.

Temperature Elevation During Neonatal and Pediatric Fixed Wing Transport in a Subtropic Climate: A Descriptive Study.

OBJECTIVE: We sought to describe the degree of temperature elevation (∆T) among children transported in a subtropical climate (Florida) via fixed wing aircraft and identify potential relationships between patient weight and ∆T. METHODS: We performed a retrospective cohort study in children < 18 years of age undergoing interfacility transport via fixed wing aircraft from January 2016 through July 2020. The study outcomes were ∆T, maximum patient temperature, ambient temperature, and heat index. Bivariate cohorts defined by patient weight (5 kg) were compared using Fisher exact, Student t-, and Wilcoxon rank sum analyses. Exploratory testing included receiver operator characteristic curve analyses and unadjusted logistic regression. RESULTS: Of the 58 children studied, 25 (43%) were ≤ 5 kg, and 33 (57%) were > 5 kg. Compared with children > 5 kg, those ≤ 5 kg had greater ∆T (0.8° ± 0.6°C vs. 0.2° ± 0.3°C), maximum patient temperature (37.3° ± 0.6°C vs. 36.8° ± 0.4°C), and proportion with ≥ 1°C ∆T (36% vs. 3%). No child > 5 kg had a temperature > 38°C, and no differences were observed for heat index or ambient temperature. Receiver operating characteristic analysis of patient weight on ∆T ≥ 1°C yielded an area under the curve of 0.86 (cutoff of 3.5 kg; sensitivity = 81.3%, specificity = 80%). Patient weight was inversely associated with ∆T ≥ 1°C (odds ratio = 0.69; 95% confidence interval, 0.49-0.96). CONCLUSIONS: Young children appear at greatest risk for developing environmental hyperthermia during interfacility fixed wing transport.

Congenital Adrenal Hyperplasia: Time to Replace 17OHP with 21-Deoxycortisol.

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency (21OHD) has a worldwide incidence of 1 in 15-20,000. Affected individuals have adrenal insufficiency and androgen excess; the androgen excess begins during fetal life, typically resulting in 46,XX disordered sexual development. In 21OHD, 17-hydroxyprogesterone (17OHP), the steroid proximal to 21-hydroxylase, accumulates. Most industrialized countries have newborn screening programs that measure 17OHP; such screening has permitted rapid detection of newborns with 21OHD, saving lives previously lost to mineralocorticoid deficiency and salt wasting. However, newborn screening is plagued by false positives. 17OHP is above most "cutoff values" in the first 24 h of life, is high in otherwise normal premature infants, and in many term infants with physiologic stress from unrelated diseases. In addition, newborn 17OHP may be elevated in other forms of CAH, including 11-hydroxylase deficiency, 3ß-hydroxysteroid dehydrogenase deficiency, and P450 oxidoreductase deficiency. In 21OHD, some of the accumulated intra-adrenal 17OHP is converted to 21-deoxycortisol (21-deoxy) by 11ß-hydroxylase (CYP11B1); 21-deoxy is not elevated in premature infants or in other forms of CAH, and hence is a more specific marker for 21OHD. However, 21-deoxy assays have not been generally available until recently, hence experience is limited. We urge clinical investigators, commercial reference laboratories, and newborn screening programs to investigate replacing 17OHP with 21-deoxy as the analyte of choice for studies of 21OHD.

The "backdoor pathway" of androgen synthesis in human male sexual development.

Mammalian sex determination (male versus female) is largely controlled by genes, whereas sex differentiation (development of reproductive structures) is largely controlled by hormones. Work in the 20th century indicated that female external anatomy was a "default" pathway of development not requiring steroids, whereas male genital development required testicular testosterone plus dihydrotestosterone (DHT) made in genital skin according to a "classic" pathway. Recent work added the description of an alternative "backdoor" pathway of androgen synthesis discovered in marsupials. Unique "backdoor steroids" are found in human hyperandrogenic disorders, and genetic disruption of the pathway causes disordered male sexual development, suggesting it plays an essential role. O'Shaughnessy and colleagues now show that the principal human backdoor androgen is androsterone and provide strong evidence that it derives from placental progesterone that is metabolized to androsterone in nontesticular tissues. These studies are essential to understanding human sexual development and its disorders.

Stability of gaseous volatile organic compounds contained in gas cylinders with different internal wall treatments.

Measurements of volatile organic compounds (VOCs) have been ongoing for decades to track growth rates and assist in curbing emissions of these compounds into the atmosphere. To accurately establish mole fraction trends and assess the role of these gas-phase compounds in atmospheric chemistry it is essential to have good calibration standards. A necessity and precursor to accurate VOC gas standards are the gas cylinders and the internal wall treatments that aid in maintaining the stability of the mixtures over long periods of time, measured in years. This paper will discuss the stability of VOC gas mixtures in different types of gas cylinders and internal wall treatments. Stability data will be given for 85 VOCs studied in gas mixtures by National Metrology Institutes and other agency laboratories. This evaluation of cylinder treatment materials is the outcome of an activity of the VOC Expert Group within the framework of the World Meteorological Organization (WMO) Global Atmospheric Watch (GAW) program.

Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline.

Objective: To update the congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency clinical practice guideline published by the Endocrine Society in 2010. Conclusions: The writing committee presents updated best practice guidelines for the clinical management of congenital adrenal hyperplasia based on published evidence and expert opinion with added considerations for patient safety, quality of life, cost, and utilization.

MECHANISMS IN ENDOCRINOLOGY: Rare defects in adrenal steroidogenesis.

Congenital adrenal hyperplasia (CAH) is a group of genetic disorders of adrenal steroidogenesis that impair cortisol synthesis, with compensatory increases in ACTH leading to hyperplastic adrenals. The term 'CAH' is generally used to mean 'steroid 21-hydroxylase deficiency' (21OHD) as 21OHD accounts for about 95% of CAH in most populations; the incidences of the rare forms of CAH vary with ethnicity and geography. These forms of CAH are easily understood on the basis of the biochemistry of steroidogenesis. Defects in the steroidogenic acute regulatory protein, StAR, disrupt all steroidogenesis and are the second-most common form of CAH in Japan and Korea; very rare defects in the cholesterol side-chain cleavage enzyme, P450scc, are clinically indistinguishable from StAR defects. Defects in 3ß-hydroxysteroid dehydrogenase, which also causes disordered sexual development, were once thought to be fairly common, but genetic analyses show that steroid measurements are generally unreliable for this disorder. Defects in 17-hydroxylase/17,20-lyase ablate synthesis of sex steroids and also cause mineralocorticoid hypertension; these are common in Brazil and in China. Isolated 17,20-lyase deficiency can be caused by rare mutations in at least three different proteins. P450 oxidoreductase (POR) is a co-factor used by 21-hydroxylase, 17-hydroxylase/17,20-lyase and aromatase; various POR defects, found in different populations, affect these enzymes differently. 11-Hydroxylase deficiency is the second-most common form of CAH in European populations but the retention of aldosterone synthesis distinguishes it from 21OHD. Aldosterone synthase deficiency is a rare salt-losing disorder. Mild, 'non-classic' defects in all of these factors have been described. Both the severe and non-classic disorders can be treated if recognized.

Tenascin-X, Congenital Adrenal Hyperplasia, and the CAH-X Syndrome.

Mutations of the CYP21A2 gene encoding adrenal 21-hydroxylase cause congenital adrenal hyperplasia (CAH). The CYP21A2 gene is partially overlapped by the TNXB gene, which encodes an extracellular matrix protein called Tenascin-X (TNX). Mutations affecting both alleles of TNXB cause a severe, autosomal recessive form of Ehlers-Danlos syndrome (EDS). Rarely, patients with severe, salt-wasting CAH have deletions of CYP21A2 that extend into TNXB, resulting in a "contiguous gene syndrome" consisting of CAH and EDS. Heterozygosity for TNXB mutations causing haploinsufficiency of TNX may be associated with the mild "hypermobility form" of EDS, which principally affects small and large joints. Studies of patients with salt-wasting CAH found that up to 10% had clinical features of EDS, associated joint hypermobility, haploinsufficiency of TNX and heterozygosity for TNXB mutations, now called "CAH-X." These patients have joint hypermobility and a spectrum of other comorbidities associated with their connective tissue disorder, including chronic arthralgia, joint subluxations, hernias, and cardiac defects. Other disorders are beginning to be associated with TNX deficiency, including familial vesicoureteral reflux and neurologic disorders. Further work is needed to delineate the full spectrum of TNX-deficient disorders, with and without associated CAH.

The Hypothalamic-Pituitary-Adrenal Axis: A Brief History.

The hypothalamic-pituitary-adrenal (HPA) axis is central to homeostasis, stress responses, energy metabolism, and neuropsychiatric function. The history of this complex system involves discovery of the relevant glands (adrenal, pituitary, hypothalamus), hormones (cortisol, corticotropin, corticotropin-releasing hormone), and the receptors for these hormones. The adrenal and pituitary were identified by classical anatomists, but most of this history has taken place rather recently, and has involved complex chemistry, biochemistry, genetics, and clinical investigation. The integration of the HPA axis with modern neurology and psychiatry has cemented the role of endocrinology in contemporary studies of behavior.

NIST Standards for Measurement, Instrument Calibration, and Quantification of Gaseous Atmospheric Compounds.

There are many gas phase compounds present in the atmosphere that affect and influence the earth's climate. These compounds absorb and emit radiation, a process which is the fundamental cause of the greenhouse effect. The major greenhouse gases in the earth's atmosphere are carbon dioxide, methane, nitrous oxide, and ozone. Some halocarbons are also strong greenhouse gases and are linked to stratospheric ozone depletion. Hydrocarbons and monoterpenes are precursors and contributors to atmospheric photochemical processes, which lead to the formation of particulates and secondary photo-oxidants such as ozone, leading to photochemical smog. Reactive gases such as nitric oxide and sulfur dioxide are also compounds found in the atmosphere and generally lead to the formation of other oxides. These compounds can be oxidized in the air to acidic and corrosive gases and contribute to photochemical smog. Measurements of these compounds in the atmosphere have been ongoing for decades to track growth rates and assist in curbing emissions of these compounds into the atmosphere. To accurately establish mole fraction trends and assess the role of these gas phase compounds in atmospheric chemistry, it is essential to have good calibration standards. The National Institute of Standards and Technology has been developing standards of many of these compounds for over 40 years. This paper discusses the development of these standards.