Development of adrenal cortex zonation

Human-like adrenal development in wild chimpanzees: A longitudinal study of urinary dehydroepiandrosterone-sulfate and cortisol

The development of the adrenal cortex varies considerably across primates, being most conspicuous in humans, where a functional zona reticularis-the site of dehydroepiandrosterone-sulfate (DHEA/S) production-does not develop until middle childhood (5-8 years). Prior reports suggest that a human-like adrenarche, associated with a sharp prepubertal increase in DHEA/S, may only occur in the genus Pan. However, the timing and variability in adrenarche in chimpanzees remain poorly described, owing to the lack of longitudinal data, or data from wild populations. Here, we use urine samples from East African chimpanzees (Pan troglodytes schweinfurthii) collected over 20 years at Kanyawara in Kibale National Park, Uganda, to trace the developmental trajectories of DHEAS (n = 1,385 samples, 53 individuals) and cortisol (n = 12,726 samples, 68 individuals). We used generalized additive models (GAM) to investigate the relationship between age, sex, and hormone levels. Adrenarche began earlier in chimpanzees (~2-3 years) compared with what has been reported in humans (6-8 years) and, unlike humans, male and female chimpanzees did not differ significantly in the timing of adrenarche nor in DHEAS concentrations overall. Similar to what has been reported in humans, cortisol production decreased through early life, reaching a nadir around puberty (8-11 years), and a sex difference emerged with males exhibiting higher urinary cortisol levels compared with females by early adulthood (15-16 years). Our study establishes that wild chimpanzees exhibit a human-like pattern of cortisol production during development and corroborates prior reports from captive chimpanzees of a human-like adrenarche, accompanied by significant developmental increases in DHEAS. While the role of these developmental hormone shifts are as yet unclear, they have been implicated in stages of rapid behavioral development once thought unique to humans, especially in regard to explaining the divergence of female and male social behavior before pubertal increases in gonadal hormones.

Peculiarities of microstructure of the suprarenal glands of rabbits with different types of autonomic tone

The article investigates the structure of the suprarenal (adrenal) glands of male rabbits (Oryctolagus cuniculus), in which, on the basis of electrocardiographic and variational-pulsometric studies, different types of autonomic tone were observed. This allowed the animals to be divided into three groups: 1) sympathicotonic rabbits; 2) normotonic rabbits; 3) parasympathicotonic rabbits. The animals of the first two groups were characterized by almost the same body weight, while weight of the rabbits of the third group was slightly higher. After euthanasia, the suprarenal glands were extracted for histological and histochemical analyses. Morphometric study of histopreparations revealed that in the normotonic rabbits the thickness of the zona glomerulosa and zona fasciculata of the suprarenal glands were of average sizes, and the area of the medulla was the smallest. The parasympathicotonic rabbits had the thickest zona glomerulosa and greatest area of the medulla, but the thinnest zona fasciculata. The sympathicotonic rabbits were observed to have the greatest thickness of the zona fasciculata of the suprarenal glands, the area of the medulla was of average values, and the thickness of the zona glumerulosa was of minimum value. The type of autonomic tone also manifests in the saturation of each of the zones with cells. The normotonic rabbits were observed to have the highest number of cells per area of 1,000 µm² in the zona fasciculata and the medulla, sympathicotonic rabbits – in the zona glomerulosa and zona reticularis, and in parasympathicotonic rabbits this parameter had average or lowest values in all the zones. The sizes of cells and their structural parts were characterized on the basis of nuclear-cytoplasmic ratio. In the zona fasciculata and medulla this parameter was highest among parasympathicotonic rabbits, and lowest in sympathicotonic rabbits. In the zona glomerulosa, almost equal values were observed in the normotonic and parasympathicotonic rabbits, while being reliably lower in sympathicotonic rabbits. By the value of nuclear-cytoplasmic ratio in the zona reticularis, the normotonic rabbits dominated, followed by the sympathicotonic animals, and the parasympathicotonic rabbits had the lowest parameters.

Correlation Between Differentiation of Adrenocortical Zones and Telomere Lengths Measured by Q-FISH

CONTEXT

Adrenocortical zonation is associated with a markedly complex developmental process, and the pathogenesis and/or etiology of many disorders of adrenocortical zonal development have remained unknown. Cells from the three adrenocortical zones are morphologically and functionally differentiated, and the mature stage of cell development or senescence has been recently reported to be correlated with telomere length. However, the telomere length of each adrenocortical zonal cell has not yet been studied in human adrenal glands.

OBJECTIVE

We aimed to study the telomere lengths of adrenocortical parenchymal cells from three different zones of the adrenal glands present during childhood, adolescence, and adulthood.

METHODS

Adrenal glands of 30 autopsied subjects, aged between 0 and 68 years, were retrieved from pathology files. The normalized telomere to centromere ratio (NTCR), an index of telomere length, was determined in the parenchymal cells of the zona glomerulosa, zona fasciculata, and zona reticularis (ZR), using quantitative fluorescence in situ hybridization.

RESULTS

NTCR of ZR cells was the longest, followed in decreasing order by that of zona glomerulosa and zona fasciculata cells in subjects aged 20 to 68 years, but no substantial differences in NTCR were detected among these three zones in the group <20 years of age. NTCR of ZR increased with age in subjects aged 20 to 68 years, whereas no important age-dependent changes in NTCR were detected in the group <20 years of age.

CONCLUSION

The telomere lengths for three zones in adrenal cortex were correlated with their differentiation in adulthood but not in childhood and adolescence.

Prenatal glucocorticoids exposure and fetal adrenal developmental programming

Clinically, we apply synthetic glucocorticoids to treat fetal and maternal diseases, such as premature labor and autoimmune diseases. Although its clinical efficacy is positive, the fetus will be exposed to exogenous synthetic glucocorticoids. Prenatal adverse environments (such as xenobiotics exposure, malnutrition, infection, hypoxia and stress) can cause fetuses overexposure to excessive endogenous maternal glucocorticoids. The level of glucocorticoids is the key to fetal tissue maturation and postnatal fate. A large number of studies have found that prenatal glucocorticoids exposure can lead to fetal adrenal dysplasia and dysfunction, continuing after birth and even into adulthood. As the core organ of fetal-originated adult diseases, fetal adrenal dysplasia is closely related to the susceptibility and occurrence of multiple chronic diseases, and there are also obvious gender differences. However, its intrauterine programming mechanisms have not been fully elucidated. This review summarizes recent advances in prenatal glucocorticoids exposure and fetal adrenal developmental programming alterations, which is of great significance for explaining adrenal developmental toxicity and the intrauterine origin of fetal-originated adult diseases.

Corticosteroid-Binding Globulin is expressed in the adrenal gland and its absence impairs corticosterone synthesis and secretion in a sex-dependent manner

Corticosteroid-binding globulin (CBG) is synthesized by the liver and secreted into the bloodstream where binds to glucocorticoids. Thus CBG has the role of glucocorticoid transport and free hormone control. In addition, CBG has been detected in some extrahepatic tissues without a known role. CBG-deficient mice show decreased total corticosterone levels with missing of classical sexual dimorphism, increased free corticosterone, higher adrenal gland size and altered HPA axis response to stress. Our aim was to ascertain whether CBG deficiency could affect the endocrine synthetic activity of adrenal gland and if the adrenal gland produces CBG. We determined the expression in adrenal gland of proteins involved in the cholesterol uptake and its transport to mitochondria and the main enzymes involved in the corticosterone, aldosterone and catecholamine synthesis. The results showed that CBG is synthesized in the adrenal gland. CBG-deficiency reduced the expression of ACTH receptor, SRB1 and the main genes involved in the adrenal hormones synthesis, stronger in females resulting in the loss of sexual dimorphism in corticosteroid adrenal synthesis, despite corticosterone content in adrenal glands from CBG-deficient females was similar to wildtype ones. In conclusion, these results point to an unexplored and relevant role of CBG in the adrenal gland functionality related to corticosterone production and release.

Regulation of stem and progenitor cells in the adrenal cortex

The adrenal cortex is an endocrine organ comprised of three histological zones, the outermost zona glomerulosa, the intermediate zona fasciculata, and the innermost zona reticularis. High plasticity of the adrenal gland is supported by pools of stem and progenitor cells that are deployed to sustain physiological and homeostatic demands. In recent decades, exciting new discoveries elucidating the identity, function, and fate of these cell populations have emerged. In this review, we describe paracrine and endocrine signaling loops that are crucial for adrenal biology, focusing on recent studies unpacking the enigmatic nature of adrenal stem and progenitor cell populations.

New strategies for applying targeted therapies to adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare, aggressive, and frequently deadly cancer. Up to 75% of all patients will eventually develop metastatic disease, and our current medical therapies for ACC provide limited - if any - survival benefit. These statistics highlight a crucial need for novel approaches. Recent studies performing comprehensive molecular profiling on ACC have illuminated that ACC is comprised of three clinically distinct molecular subtypes, bearing differential regulation of cell cycle, epigenetics, Wnt/β-catenin signaling, PKA signaling, steroidogenesis and immune cell biology. Furthermore, these studies have spurred the development of molecular subtype-based biomarkers, contextualized outcomes of recent clinical trials, and advanced our understanding of the underlying biology of adrenocortical homeostasis and cancer. In this review, we describe these findings and their implications for new strategies to apply targeted therapies to ACC.

Hypercortisolism and primary aldosteronism caused by bilateral adrenocortical adenomas: a case report

BACKGROUND

Co-existing Cushing's syndrome and primary aldosteronism caused by bilateral adrenocortical adenomas, secreting cortisol and aldosterone, respectively, have rarely been reported. Precise diagnosis and management of this disorder constitute a challenge to clinicians due to its atypical clinical manifestations and laboratory findings.

CASE PRESENTATION

We here report a Chinese male patient with co-existing Cushing's syndrome and primary aldosteronism caused by bilateral adrenocortical adenomas, who complained of intermittent muscle weakness for over 3 years. Computed tomography scans revealed bilateral adrenal masses. Undetectable ACTH and unsuppressed cortisol levels by dexamethasone suggested ACTH-independent Cushing's syndrome. Elevated aldosterone to renin ratio and unsuppressed plasma aldosterone concentration after saline infusion test suggested primary aldosteronism. Adrenal venous sampling adjusted by plasma epinephrine revealed hypersecretion of cortisol from the left adrenal mass and of aldosterone from the right one. A sequential bilateral laparoscopic adrenalectomy was performed. The cortisol level was normalized after partial left adrenalectomy and the aldosterone level was normalized after subsequent partial right adrenalectomy. Histopathological evaluation of the resected surgical specimens, including immunohistochemical staining for steroidogenic enzymes, revealed a left cortisol-producing adenoma and a right aldosterone-producing adenoma. The patient's symptoms and laboratory findings resolved after sequential adrenalectomy without any pharmacological treatment.

CONCLUSIONS

Adrenal venous sampling is essential in diagnosing bilateral functional adrenocortical adenomas prior to surgery. Proper interpretation of the laboratory findings is particularly important in these patients. Immunohistochemistry may be a valuable tool to identify aldosterone/cortisol-producing lesions and to validate the clinical diagnosis.

Bilateral adrenal-renal fusion: A radiological diagnosis

In normal anatomy, the kidneys and adrenal glands are contained within the renal fascia and separated by a connective tissue capsule derived from mesenchymal tissue. Incomplete encapsulation can occur during embryonic development, resulting in adrenal-renal fusion. The true incidence of this developmental anomaly is unknown, as it has primarily been described in the literature following incidental detection on surgical or histological examination. We report the first documented case of bilateral adrenal-renal fusion, diagnosed radiologically.

The Effects of High Peripubertal Caffeine Exposure on the Adrenal Gland in Immature Male and Female Rats

The consumption of high levels of dietary caffeine has increased in children and adolescents. Human and animal studies have shown that chronic intake of high doses of caffeine affects serum glucocorticoid levels. Given that glucocorticoids play a role in peripubertal organ growth and development, chronic high doses of caffeine during puberty might impair maturation of the adrenal glands. To evaluate any effects of caffeine exposure on growing adrenal glands, 22-day-old male (n = 30) and female Sprague Dawley rats (n = 30) were divided into three groups (n = 10/group); group 1 received tap water (control) and groups 2 and 3 received water containing 120 and 180 mg/kg/day caffeine, respectively, via gavage for 4 weeks. At the end of the experiment, adrenal glands were weighed and processed for histological analysis. Relative adrenal weights increased in both groups of caffeine-fed males and females, whereas absolute weights were decreased in the females. In the female caffeine-fed groups the adrenal cortical areas resembled irregularly arranged cords and the medullary area was significantly increased, whereas no such effects were seen in the male rats. Our results indicate that the harmful effects of caffeine on the adrenal glands of immature rats differ between females and males. Although female rats seemed to be more susceptible to damage based on the changes in the microarchitecture of the adrenal glands, caffeine affected corticosterone production in both female and male rats. In addition, increased basal adrenocorticotropic hormone levels in caffeine-fed groups may reflect decreased cortical function. Therefore, caffeine may induce an endocrine imbalance that disturbs the establishment of the hypothalamo–pituitary adrenal axis during puberty, thereby leading to abnormal stress responses.

Precocious pubertal events in Chilean children: ethnic disparities

PURPOSE

Puberty onset exhibits remarkable inter-individual and ethnic differences. 5% of Chileans are indigenous but puberty ethnic disparities have not been studied. We aim for evaluating precocious puberty prevalence in children with Mapuche ancestry vs non-indigenous Chilean children (according to their surnames).

METHODS

Longitudinal cohort study: 1003 children (50.2% girls) participating in the Growth and Obesity Chilean Cohort Study (GOCS) were studied. Annual anthropometry was measured since 4-7 years. Subsequently, Tanner staging and anthropometry were measured every 6 months. In girls, Tanner stage was assessed by breast palpation and in boys by testicular volume measurements. The cohort was stratified in three groups depending on Mapuche surname numbers as follows: (A) no indigenous surnames (n = 811), (B) one to two indigenous surnames (n = 147), and (C) three or more indigenous surnames (n = 45). We evaluated the prevalence of precocious thelarche, pubarche, menarche and gonadarche (testicular volume ≥ 4 ml-G2), using a cutoff age of 8 years in girls and 9 years in boys while controlling for socioeconomic status, body mass index, waist circumference, IGF-1 and DHEAS at 7 years.

RESULTS

In girls, no significant differences were observed. On the contrary, in boys, precocious gonadarche prevalence was higher in group C (29.2%) vs group A (6.0%) and vs group B (10.5%) (p =0.001, p = 0.004, respectively). Increased precocious gonadarche and pubarche risks in group C were observed even after adjustment [OR 7.31; 95% IC (2.32-23.51); p = 0.001] and [OR 6.17, 95% CI (1.62-23.49); p = 0.008], respectively.

CONCLUSION

Indigenous origin in Chile is an independent risk factor for precocious gonadarche and pubarche in boys but not in girls.

Adrenal steroids in female hypothyroid neonates: Unraveling an association between thyroid hormones & adrenal remodeling

CONTEXT

The adrenal gland undergoes significant remodeling during the neonatal period, an essential developmental process that still remains incompletely understood. With respect to control over the remodeling process and, specifically, the role of thyroid hormones (TH), no human studies have been published. The effect of both hypo- and hyper-thyroidism has only been evaluated in adults, focusing on the mature adrenal. Recently, Huang et al identified expression of the TH receptor β1 in the mouse adrenal X-zone and demonstrated that TH administration could alter the postnatal adrenal remodeling process.

OBJECTIVE

To address whether TH influence adrenal steroid profiles and adrenal remodeling during the neonatal period.

METHODS

We compared the adrenal steroid profile of a naturally occurring prototype, female neonates with severe congenital hypothyroidism (CH, n=22, upon diagnosis of CH), with that of euthyroid neonates (n=20).

RESULTS

Significantly higher levels of adrenal steroids (17-OH-progesterone, DHEAS, Δ4- androstenedione and testosterone) were measured in neonates with severe CH compared to euthyroid neonates, returning within normal range after euthyroid state had been established on L-thyroxine replacement therapy whereas cortisol levels did not differ. TSH values in the CH group were positively, while FT4 levels were negatively correlated with circulating adrenal steroids.

CONCLUSIONS

The hormonal profile of female neonates with severe CH suggests a more active adrenal fetal zone than controls. These data indirectly associate TH with the adrenal remodeling and maturation process in humans. Based on our results we suggest that severe hypothyroidism decelerates the involution of the adrenal fetal zone that normally occurs postnatally.

A ZNRF3-dependent Wnt/β-catenin signaling gradient is required for adrenal homeostasis

The transmembrane E3 ubiquitin ligases ZNRF3 and RNF43 antagonize Wnt signaling by promoting degradation of frizzled receptors. Here, Basham et al. demonstrate that adrenocortical-specific loss of ZNRF3, but not RNF43, results in adrenal hyperplasia that depends on Porcupine-mediated Wnt ligand secretion.

Spatiotemporal control of Wnt signaling is essential for the development and homeostasis of many tissues. The transmembrane E3 ubiquitin ligases ZNRF3 (zinc and ring finger 3) and RNF43 (ring finger protein 43) antagonize Wnt signaling by promoting degradation of frizzled receptors. ZNRF3 and RNF43 are frequently inactivated in human cancer, but the molecular and therapeutic implications remain unclear. Here, we demonstrate that adrenocortical-specific loss of ZNRF3, but not RNF43, results in adrenal hyperplasia that depends on Porcupine-mediated Wnt ligand secretion. Furthermore, we discovered a Wnt/β-catenin signaling gradient in the adrenal cortex that is disrupted upon loss of ZNRF3. Unlike β-catenin gain-of-function models, which induce high Wnt/β-catenin activation and expansion of the peripheral cortex, ZNRF3 loss triggers activation of moderate-level Wnt/β-catenin signaling that drives proliferative expansion of only the histologically and functionally distinct inner cortex. Genetically reducing β-catenin dosage significantly reverses the ZNRF3-deficient phenotype. Thus, homeostatic maintenance of the adrenal cortex is dependent on varying levels of Wnt/β-catenin activation, which is regulated by ZNRF3.

Associations between repeated measures of maternal urinary phthalate metabolites during pregnancy and cord blood glucocorticoids

BACKGROUND

Previous studies have suggested that phthalates might disrupt fetal steroidogenesis. However, the evidence of the effects of prenatal phthalate exposure across pregnancy on fetal glucocorticoids was insufficient.

OBJECTIVE

We investigated the associations between urinary phthalate metabolites across pregnancy and cord blood glucocorticoids in a prospective birth cohort.

METHODS

Our study included 553 mother-infant pairs from a prospective birth cohort conducted in Wuhan, China. Maternal urine samples were collected at 14, 24 and 36 weeks of gestation (mean). Urinary phthalate metabolites and cord blood glucocorticoids (cortisol and cortisone) were measured. Generalized estimating equation models were conducted to explore the relationships of phthalate metabolite concentrations at each trimester and glucocorticoid levels.

RESULTS

Among the participants, mono‑benzyl phthalate (MBzP) in the first trimester was associated with higher cortisol/cortisone ratio concentrations, and mono‑(2‑ethyl‑5‑carboxypentyl) phthalate (MECPP) and mono‑(2‑ethyl‑5‑oxohexyl) phthalate (MEOHP) measured in the third trimester were associated with decreased cortisone. Moreover, the associations between phthalates and glucocorticoids varied by sex. Among the female infants, each 10-fold increase in several maternal urinary phthalate metabolite concentrations in 1st and 3rd trimester was associated with the increased glucocorticoid levels with percent changes ranged from 16.2%-55.9%. However, among male infants, each 10-fold increase in maternal urinary MECPP, mono‑(2‑ethyl‑5‑hydroxyhexyl) phthalate (MEHHP) and MEOHP in 3rd trimester was associated with 20.8%-36.3% decreased cortisol and cortisone levels, respectively.

CONCLUSION

We have shown that prenatal phthalate exposure during early and late trimester disrupted the infant steroidogenesis and these associations might be modified by infant sex. To the best of our knowledge, this is the first study to evaluate phthalate exposure at three trimesters during pregnancy in relation to infant glucocorticoids.

The Biology of Normal Zona Glomerulosa and Aldosterone-Producing Adenoma: Pathological Implications

The identification of several germline and somatic ion channel mutations in aldosterone-producing adenomas (APAs) and detection of cell clusters that can be responsible for excess aldosterone production, as well as the isolation of autoantibodies activating the angiotensin II type 1 receptor, have rapidly advanced the understanding of the biology of primary aldosteronism (PA), particularly that of APA. Hence, the main purpose of this review is to discuss how discoveries of the last decade could affect histopathology analysis and clinical practice. The structural remodeling through development and aging of the human adrenal cortex, particularly of the zona glomerulosa, and the complex regulation of aldosterone, with emphasis on the concepts of zonation and channelopathies, will be addressed. Finally, the diagnostic workup for PA and its subtyping to optimize treatment are reviewed.

Human Adrenal Cortex: Epigenetics and Postnatal Functional Zonation

The human adrenal cortex, involved in adaptive responses to stress, fluid homeostasis, and secondary sexual characteristics, arises from a tightly regulated development of a zone and cell type-specific secretory pattern. However, the molecular mechanisms governing adrenal zonation, particularly postnatal zona reticularis development, which produce adrenal androgens in a lifetime-specific manner, remain poorly understood. Epigenetic events, including DNA and histone modifications as well as regulation by noncoding RNAs, are crucial in establishing or maintaining the expression pattern of specific genes and thus contribute to the stability of a specific differentiation state. Emerging evidence points to epigenetics as another regulatory layer that could contribute to establishing the adrenal zone-specific pattern of enzyme expression. Here, we outline the developmental milestones of the human adrenal cortex, focusing on current advances and understanding of epigenetic regulation of postnatal functional zonation. Numerous questions remain to be addressed emphasizing the need for additional investigations to elucidate the role of epigenetics in the human adrenal gland. Ultimately, improved understanding of the epigenetic factors involved in adrenal development and function could lead to novel therapeutic interventions.

Feminizing Adrenocortical Carcinoma: The Source of Estrogen Production and the Role of Adrenal-Gonadal Dedifferentiation

BACKGROUND

Feminizing adrenocortical carcinoma (ACC) is rare. The source of estrogen production and the underlying mechanism remain unclear.

OBJECTIVE

In the current study, we investigated the source and the molecular mechanism of estrogen production in feminizing ACC.

METHODS

A total of 46 consecutive patients with a diagnosis of ACC were recruited in our center. We described the clinical characteristics and steroid hormone profile of the peripheral and adrenal vein. In both feminizing ACC tissues and cell lines, we investigated the expression of steroidogenic biomarkers and β-catenin pathways by quantitative PCR and immunohistochemical staining. The effects of Wnt inhibitors on steroidogenesis were also analyzed in NCI-H295R cells.

RESULTS

A total of 46 consecutive patients with ACC were analyzed, and 25 had functional ACC. Four patients received a diagnosis of feminizing ACC based on feminizing manifestations, high levels of estradiol that were normalized after surgery, and histological Weiss score. Gonadal steroidogenic biomarkers including CYP19A1, HSD17B3, and LHCGR were markedly elevated in the feminizing ACC tissues. Adrenal vein sampling and liquid chromatography-tandem mass spectrometry suggested high CYP19A1 activity in the adrenal mass. β-catenin expression was also elevated. When treated with niclosamide and PNU-74654, the H295R cell line showed a decrease in β-catenin expression, cell proliferation, and steroid secretion. All steroid hormone enzymes were inhibited, whereas CYP19A1, HSD17B3, and LHCGR mRNA increased.

CONCLUSIONS

Feminizing ACC can express high levels of CYP19A1, thus ectopically producing estrogens. Wnt pathway activation and dedifferentiation toward common adrenal-gonadal precursor cells may be the underlying mechanisms.

Human fetal adrenal cells retain age-related stem- and endocrine-differentiation potential in culture

The adrenal gland is a multiendocrine organ with a steroidogenic mesenchymal cortex and an inner catecholamine-producing medulla of neuroendocrine origin. After embryonic development, this plastic organ undergoes a functional postnatal remodeling. Elucidating these complex processes is pivotal for understanding the early bases of functional endocrine disorders and tumors affecting the mature gland. We developed an in vitro human adrenal cell model derived from fetal adrenal specimens at different gestational ages, consisting of neuroendocrine and cortical components and expressing the zona and functional markers of the original fetal organ. These cortical and neuroendocrine progenitor cells retain in vitro an intrinsic gestational-age-related differentiation and functional program. In vitro these cells spontaneously form 3-dimensional structure organoids with a structure similar to the fetal gland. The organoids show morphofunctional features and adrenal steroidogenic factor, steroid acute regulatory, cytochrome-P450-17A1, dosage-sensitive, sex-reversal, adrenal hypoplasia-critical region on chromosome X protein , NOTCH1, and nephroblastoma overexpressed/cysteine-rich protein 61/connective tissue growth factor/nephroblastoma overexpressed gene-3; stem (BMI1, nestin); and chromaffin (chromogranin A, tyrosine hydroxylase) markers similar to those of the populations of origin. This in vitro human adrenal system represents a unique but preliminar model for investigating the pathophysiological processes underlying physiologic adrenal remodeling and pathologic alterations involved in organ hypo- and hyperplasia and cancer.-Poli, G., Sarchielli, E., Guasti, D., Benvenuti, S., Ballerini, L., Mazzanti, B., Armignacco, R., Cantini, G., Lulli, M., Chortis, V., Arlt, W., Romagnoli, P., Vannelli, G. B., Mannelli, M., Luconi, M. Human fetal adrenal cells retain age-related stem- and endocrine-differentiation potential in culture.

The human adrenal cortex: growth control and disorders

This review summarizes key knowledge regarding the development, growth, and growth disorders of the adrenal cortex from a molecular perspective. The adrenal gland consists of two distinct regions: the cortex and the medulla. During embryological development and transition to the adult adrenal gland, the adrenal cortex acquires three different structural and functional zones. Significant progress has been made in understanding the signaling and molecules involved during adrenal cortex zonation. Equally significant is the knowledge obtained regarding the action of peptide factors involved in the maintenance of zonation of the adrenal cortex, such as peptides derived from proopiomelanocortin processing, adrenocorticotropin and N-terminal proopiomelanocortin. Findings regarding the development, maintenance and growth of the adrenal cortex and the molecular factors involved has improved the scientific understanding of disorders that affect adrenal cortex growth. Hypoplasia, hyperplasia and adrenocortical tumors, including adult and pediatric adrenocortical adenomas and carcinomas, are described together with findings regarding molecular and pathway alterations. Comprehensive genomic analyses of adrenocortical tumors have shown gene expression profiles associated with malignancy as well as methylation alterations and the involvement of miRNAs. These findings provide a new perspective on the diagnosis, therapeutic possibilities and prognosis of adrenocortical disorders.

The molecular pathways underlying early gonadal development

The body of knowledge surrounding reproductive development spans the fields of genetics, anatomy, physiology and biomedicine, to build a comprehensive understanding of the later stages of reproductive development in humans and animal models. Despite this, there remains much to learn about the bi-potential progenitor structure that the ovary and testis arise from, known as the genital ridge (GR). This tissue forms relatively late in embryonic development and has the potential to form either the ovary or testis, which in turn produce hormones required for development of the rest of the reproductive tract. It is imperative that we understand the genetic networks underpinning GR development if we are to begin to understand abnormalities in the adult. This is particularly relevant in the contexts of disorders of sex development (DSDs) and infertility, two conditions that many individuals struggle with worldwide, with often no answers as to their aetiology. Here, we review what is known about the genetics of GR development. Investigating the genetic networks required for GR formation will not only contribute to our understanding of the genetic regulation of reproductive development, it may in turn open new avenues of investigation into reproductive abnormalities and later fertility issues in the adult.

Interplay between estrogen-related receptors and steroidogenesis-controlling molecules in adrenals. In vivo and in vitro study

Estrogen-related receptors (ERRs) α, β and γ appear to be novel molecules implicated in estrogen signaling. We blocked and activated ERRs in mouse (C57BL/6) adrenals and adrenocortical cells (H295R) using pharmacological agents XCT 790 (ERRα antagonist) and DY131 (ERRβ/γ agonist), respectively. Mice were injected with XCT 790 or DY131 (5 μg/kg bw) while cells were exposed to XCT 790 or DY131 (0.5 μg/L). Irrespectively of the agent used, changes in adrenocortical cell morphology along with changes in lutropin, cholesterol levels and estrogen production were found. Diverse and complex ERRs regulation of multilevel-acting steroidogenic proteins (perilipin; PLIN, cytochrome P450 side-chain cleavage; P450scc, translocator protein; TSPO, steroidogenic acute regulatory protein; StAR, hormone sensitive lipase; HSL and HMG-CoA reductase; HMGCR) was revealed. Blockage of ERRα decreased P450scc, StAR and TSPO expressions. Activation of ERRβ/γ increased P450scc, StAR and HMGCR while decreased HSL expressions. PLIN expression increased either after XCT 790 or DY131 treatment. Additionally, treatment with both XCT 790 or DY131 decreased activity of Ras/Raf, Erk and Akt indicating their involvement in control of morphology and steroidogenic function of cortex cells. ERRs are important in maintaining morpho-function of cortex cells through action in specific, opposite, or common manner on steroidogenic molecules.

Mutation of HSD3B2 Gene and Fate of Dehydroepiandrosterone

3βHSD2 enzyme is crucial for adrenal and gonad steroid biosynthesis. In enzyme deficiency states, due to recessive loss-of-function HSD3B2 mutations, steroid flux is altered and clinical manifestations result. Deficiency of 3βHSD2 activity in the adrenals precludes normal aldosterone and cortisol synthesis and the alternative backdoor and 11-oxygenated C19 steroid pathways and the flooding of cortisol precursors along the Δ5 pathway with a marked rise in DHEA and DHEAS production. In gonads, it precludes normal T and estrogen synthesis. Here, we review androgen-dependent male differentiation of the external genitalia in humans and link this to female development and steroidogenesis in the developing adrenal cortex. The molecular mechanisms governing postnatal adrenal cortex zonation and ZR development were also revised. This chapter will review relevant clinical, hormonal, and genetic aspects of 3βHSD2 deficiency with emphasis on the significance of alternate fates encountered by steroid hormone precursors in the adrenal gland and gonads. Our current knowledge of the process of steroidogenesis and steroid action is derived from pathological conditions. In humans the 3βHSD2 deficiency represents a model of nature that reinforces our knowledge about the role of the steroidogenic alternative pathway in sex differentiation in both sexes. However, the physiological role of the high serum DHEAS levels in fetal life as well as after adrenarche remains to be elucidated.

TCF21/POD-1, a Transcritional Regulator of SF-1/NR5A1, as a Potential Prognosis Marker in Adult and Pediatric Adrenocortical Tumors

With recent progress in understanding the pathogenesis of adrenocortical tumors (ACTs), identification of molecular markers to predict their prognosis has become possible. Transcription factor 21 (TCF21)/podocyte-expressed 1 (POD1) is a transcriptional regulatory protein expressed in mesenchymal cells at sites of epithelial-mesenchymal transition during the development of different systems. Adult carcinomas express less TCF21 than adenomas, in addition, the KEGG pathway analysis has shown that BUB1B, among others genes, is negatively correlated with TCF21 expression. The difference between BUB1B and PTEN-induced putative kinase 1 (PINK1) expression has been described previously to be associated with survival in adult but not in pediatric carcinomas. Here, we analyzed the gene expression of TCF21, BUB1B, PINK1, and NR5A1 in adult and pediatric ACTs. We found a negative correlation between the relative expression levels of TCF21 and BUB1B in adult ACTs, but the relative expression levels of TCF21, BUB1B, PINK1, and NR5A1 were similar in childhood ACTs. In addition, we propose using the subtracted expression levels of the TCF21/POD-1 genes as a predictor of overall survival (OS) in adult carcinomas and TCF21-NR5A1 as a predictor of malignancy for pediatric tumors in patients aged <5 years. These results require further validation in different cohorts of both adult and pediatric samples. Finally, we observed that the OS for patients aged <5 years was markedly favorable compared with that for patients >5 years as well as adult patients with carcinoma. In summary, we propose TCF21/POD-1 as a new prognostic marker in adult and pediatric ACTs.

Targeting CXCR4 (CXC Chemokine Receptor Type 4) for Molecular Imaging of Aldosterone-Producing Adenoma

Primary aldosteronism is the most frequent cause of secondary hypertension and is associated with increased morbidity and mortality compared with hypertensive controls. The central diagnostic challenge is the differentiation between bilateral and unilateral disease, which determines treatment options. Bilateral adrenal venous sampling, currently recommended for differential diagnosis, is an invasive procedure with several drawbacks, making it desirable to develop novel noninvasive diagnostic tools. When investigating the expression pattern of chemokine receptors by quantitative real-time polymerase chain reaction and immunohistochemistry, we observed high expression of CXCR4 (CXC chemokine receptor type 4) in aldosterone-producing tissue in normal adrenals, adjacent adrenal cortex from adrenocortical adenomas, and in aldosterone-producing adenomas (APA), correlating strongly with the expression of CYP11B2 (aldosterone synthase). In contrast, CXCR4 was not detected in the majority of nonfunctioning adenomas that are frequently found coincidently. The specific CXCR4 ligand 68Ga-pentixafor has recently been established as radiotracer for molecular imaging of CXCR4 expression and showed strong and specific binding to cryosections of APAs in our study. We further investigated 9 patients with primary aldosteronism because of APA by 68Ga-pentixafor-positron emission tomography. The tracer uptake was significantly higher on the side of increased adrenocortical aldosterone secretion in patients with APAs compared with patients investigated by 68Ga-pentixafor-positron emission tomography for other causes. Molecular imaging of aldosterone-producing tissue by a CXCR4-specific ligand may, therefore, be a highly promising tool for noninvasive characterization of patients with APAs.

Phthalate and bisphenol A exposure during in utero windows of susceptibility in relation to reproductive hormones and pubertal development in girls

BACKGROUND

Over the past several decades, the age of pubertal onset in girls has shifted downward worldwide. As early pubertal onset is associated with increased risky behavior and psychological issues during adolescence and cardiometabolic disease and cancer in adulthood, this is an important public health concern. Exposure to endocrine disrupting chemicals during critical windows of in utero development may play a role in this trend. Our objective was to investigate trimester-specific phthalate and BPA exposure in relation to pubertal development among girls in the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) birth cohort.

METHODS

We measured maternal urinary phthalate metabolites and BPA in samples collected during the first, second, and third trimesters of pregnancy. To assess reproductive development among their female children, we measured serum testosterone, estradiol, dehydroepiandrosterone sulfate (DHEA-S), inhibin B, and sex hormone-binding globulin (SHBG), and assessed sexual maturation, including Tanner staging for breast and pubic hair development and menarche status, at age 8-13 years (n = 120). We used linear and logistic regression to examine measures of trimester-specific in utero exposure as predictors of peripubertal hormone levels and pubertal onset, respectively. In secondary analyses, we evaluated estimated exposure at the midpoint of the first trimester and rates of change in exposure across pregnancy in relation to outcomes.

RESULTS

Several phthalate metabolites measured throughout in utero development were associated with higher serum testosterone concentrations, while a number of metabolites measured in the third trimester were associated with higher DHEA-S. For example, an interquartile range (IQR) increase in mean monoethyl phthalate (MEP) levels across pregnancy was associated with 44% higher peripubertal testosterone (95% CI: 13-83%), while an IQR increase in di-2-ethylhexyl phthalate metabolites (ΣDEHP) specifically in the third trimester was associated with 25% higher DHEA-S (95%CI: 4.7-47%). In IQR increase in mean mono-2-ethylhexyl phthalate (MEHP) levels across pregnancy was associated with lower odds of having a Tanner Stage >1 for breast development (OR = 0.32, 95%CI: 0.11-0.95), while MEHP in the third trimester was associated with higher odds of having a Tanner Stage >1 for pubic hair development (OR = 3.76, 95%CI: 1.1-12.8). Results from secondary analyses were consistent with findings from our main analysis.

CONCLUSION

These findings suggest that female reproductive development may be more vulnerable to the effects of phthalate or BPA exposure during specific critical periods of in utero development. This highlights the need for comprehensive characterizations of in utero exposure and consideration of windows of susceptibility in developmental epidemiological studies. Future research should consider repeated measures of in utero phthalate and BPA exposure within each trimester and across pregnancy.

Developmental origins of the human hypothalamic-pituitary-adrenal axis

INTRODUCTION

The developmental origins of disease or fetal programming model predicts that intrauterine exposures have life long consequences for physical and psychological health. Prenatal programming of the fetal hypothalamic-pituitary-adrenal (HPA) axis is proposed as a primary mechanism by which early experiences are linked to later disease risk. Areas covered: This review describes the development of the fetal HPA axis, which is determined by an intricately timed cascade of endocrine events during gestation and is regulated by an integrated maternal-placental-fetal steroidogenic unit. Mechanisms by which stress-induced elevations in hormones of maternal, fetal, or placental origin influence the structure and function of the emerging fetal HPA axis are discussed. Recent prospective studies documenting persisting associations between prenatal stress exposures and altered postnatal HPA axis function are summarized, with effects observed beginning in infancy into adulthood. Expert commentary: The results of these studies are synthesized, and potential moderating factors are discussed. Promising areas of further research highlighted include epigenetic mechanisms and interactions between pre and postnatal influences.

AgRP-Expressing Adrenal Chromaffin Cells Are Involved in the Sympathetic Response to Fasting

Fasting evokes a homeostatic response that maintains circulating levels of energy-rich metabolites and increases the drive to eat. Centrally, this reflex activates a small population of hypothalamic neurons that are characterized by the expression of AgRP, a neuropeptide with an extremely restricted distribution. Apart from the hypothalamus, the only other site with substantial expression is the adrenal gland, but there is disagreement about which cells synthesize AgRP. Using immunohistochemistry, flow cytometry, and reverse transcription-polymerase chain reaction, we show AgRP is present in the mouse adrenal medulla and is expressed by neuroendocrine chromaffin cells that also synthesize the catecholamines and neuropeptide Y. Short-term fasting led to an increase in adrenal AgRP expression. Because AgRP can act as an antagonist at MC3/4 receptors, we tested whether melanotan II, an MC3/4 receptor agonist, could regulate pre- and postsynaptic signaling within the adrenal medulla. Melanotan II decreased the paired-pulse ratio of evoked synaptic currents recorded in chromaffin cells; this effect was blocked by exogenous AgRP. In contrast, neither melanotan II nor AgRP altered the optogenetically evoked release of catecholamines from isolated chromaffin cells. These results are consistent with the idea that AgRP regulates the strength of the sympathetic input by modulation of presynaptic MC3/4 receptors located on preganglionic neurons. We conclude that a small population of neuroendocrine cells in the adrenal medulla, and the arcuate nucleus of the hypothalamus, express AgRP and neuropeptide Y and are functionally involved in the systemic response to fasting.

Genetics of Adrenocortical Development and Tumors

This article links the understanding of developmental physiology of the adrenal cortex to adrenocortical tumor formation. Many molecular mechanisms that lead to formation of adrenocortical tumors have been discovered via next-generation sequencing approaches. The most frequently mutated genes in adrenocortical tumors are also factors in normal adrenal development and homeostasis, including those that alter the p53 and Wnt/β-catenin pathways. In addition, dysregulated protein kinase A signaling and ARMC5 mutations have been identified as key mediators of adrenocortical tumorigenesis. The growing understanding of genetic changes that orchestrate adrenocortical development and disease pave the way for potential targeted treatment strategies.

Age-Related Autonomous Aldosteronism

BACKGROUND

Both aging and inappropriate secretion of aldosterone increase the risk for developing cardiovascular disease; however, the influence of aging on aldosterone secretion and physiology is not well understood.

METHODS

The relationship between age and adrenal aldosterone synthase (CYP11B2) expression was evaluated in 127 normal adrenal glands from deceased kidney donors (age, 9 months to 68 years). Following immunohistochemistry, CYP11B2-expressing area and areas of abnormal foci of CYP11B2-expressing cells, called aldosterone-producing cell clusters, were analyzed. In a separate ancillary clinical study of 677 participants without primary aldosteronism, who were studied on both high and restricted sodium diets (age, 18-71 years), we used multivariable linear regression to assess the independent associations between age and renin-angiotensin-aldosterone system physiology.

RESULTS

In adrenal tissue, the total CYP11B2-expressing area was negatively correlated with age (r=-0.431, P<0.0001), whereas the total aldosterone-producing cell cluster area was positively correlated with age (r=0.390, P<0.0001). The integrated ratio of aldosterone-producing cell cluster to CYP11B2-expressing area was most strongly and positively correlated with age (r=0.587, P<0.0001). When participants in the clinical study were maintained on a high sodium balance, renin activity progressively declined with older age, whereas serum and urinary aldosterone did not significantly decline. Correspondingly, the aldosterone-to-renin ratio was positively and independently associated with older age (adjusted β=+5.54 ng/dL per ng/mL per hour per 10 years, P<0.001). In contrast, when participants were assessed under sodium-restricted conditions, physiological stimulation of aldosterone was blunted with older age (β=-4.6 ng/dL per 10 years, P<0.0001).

CONCLUSIONS

Aging is associated with a pattern of decreased normal zona glomerulosa CYP11B2 expression and increased aldosterone-producing cell cluster expression. This histopathologic finding parallels an age-related autonomous aldosteronism and abnormal aldosterone physiology that provides 1 potential explanation for age-related cardiovascular risk.

A genomic atlas of human adrenal and gonad development

BACKGROUND

In humans, the adrenal glands and gonads undergo distinct biological events between 6-10 weeks post conception (wpc), such as testis determination, the onset of steroidogenesis and primordial germ cell development. However, relatively little is currently known about the genetic mechanisms underlying these processes. We therefore aimed to generate a detailed genomic atlas of adrenal and gonad development across these critical stages of human embryonic and fetal development.

METHODS

RNA was extracted from 53 tissue samples between 6-10 wpc (adrenal, testis, ovary and control). Affymetrix array analysis was performed and differential gene expression was analysed using Bioconductor. A mathematical model was constructed to investigate time-series changes across the dataset. Pathway analysis was performed using ClueGo and cellular localisation of novel factors confirmed using immunohistochemistry.

RESULTS

Using this approach, we have identified novel components of adrenal development (e.g. ASB4, NPR3) and confirmed the role of SRY as the main human testis-determining gene. By mathematical modelling time-series data we have found new genes up-regulated with SOX9 in the testis (e.g. CITED1), which may represent components of the testis development pathway. We have shown that testicular steroidogenesis has a distinct onset at around 8 wpc and identified potential novel components in adrenal and testicular steroidogenesis (e.g. MGARP, FOXO4, MAP3K15, GRAMD1B, RMND2), as well as testis biomarkers (e.g. SCUBE1). We have also shown that the developing human ovary expresses distinct subsets of genes (e.g. OR10G9, OR4D5), but enrichment for established biological pathways is limited.

CONCLUSION

This genomic atlas is revealing important novel aspects of human development and new candidate genes for adrenal and reproductive disorders.

A genomic atlas of human adrenal and gonad development

Background: In humans, the adrenal glands and gonads undergo distinct biological events between 6-10 weeks post conception (wpc), such as testis determination, the onset of steroidogenesis and primordial germ cell development. However, relatively little is currently known about the genetic mechanisms underlying these processes. We therefore aimed to generate a detailed genomic atlas of adrenal and gonad development across these critical stages of human embryonic and fetal development.

Methods: RNA was extracted from 53 tissue samples between 6-10 wpc (adrenal, testis, ovary and control). Affymetrix array analysis was performed and differential gene expression was analysed using Bioconductor. A mathematical model was constructed to investigate time-series changes across the dataset. Pathway analysis was performed using ClueGo and cellular localisation of novel factors confirmed using immunohistochemistry.

Results: Using this approach, we have identified novel components of adrenal development (e.g. ASB4, NPR3) and confirmed the role of SRY as the main human testis-determining gene. By mathematical modelling time-series data we have found new genes up-regulated with SOX9 in the testis (e.g. CITED1), which may represent components of the testis development pathway. We have shown that testicular steroidogenesis has a distinct onset at around 8 wpc and identified potential novel components in adrenal and testicular steroidogenesis (e.g. MGARP, FOXO4, MAP3K15, GRAMD1B, RMND2), as well as testis biomarkers (e.g. SCUBE1). We have also shown that the developing human ovary expresses distinct subsets of genes (e.g. OR10G9, OR4D5), but enrichment for established biological pathways is limited.

Conclusion: This genomic atlas is revealing important novel aspects of human development and new candidate genes for adrenal and reproductive disorders.

DNA methylation is not involved in specific down-regulation of HSD3B2, NR4A1 and RARB genes in androgen-secreting cells of human adrenal cortex

We hypothesized that DNA methylation is involved in human adrenal functional zonation. mRNAs expression and methylation pattern of RARB, NR4A1 and HSD3B2 genes in human adrenal tissues (HAT) and in pediatric virilizing adrenocortical tumors (VAT) were analyzed. For analysis of the results samples were divided into 3 age groups according to FeZ involution, pre and post-adrenarche ages. In all HAT, similar RARB mRNA was found including microdissected zona reticularis (ZR) and zona fasciculata, but HSD3B2 and NR4A1 mRNAs were lower in ZR (p < 0.05). NR4A1 and RARB promoters remained unmethylated in HAT and VAT. No adrenal zone-specific differences in NR4A1 methylation were observed. In summary, RARB was not associated with ZR-specific downregulation of HSD3B2 in postnatal human adrenocotical zonation. DNA methylation would not be involved in NR4A1 adrenocortical cell-type specific downregulation. Lack of CpG islands in HSD3B2 suggested that HSD3B2 ZR-specific downregulation would not be directly mediated by DNA methylation.

Function of CYP11A1 in the mitochondria

Steroids are synthesized from the adrenal glands and gonads by enzymes of the cytochromes P450 and hydroxysteroid dehydrogenase in nature. These enzymes are located in the membrane of endoplasmic reticulum and mitochondria to catalyze redox reactions using electrons transported from the membrane. In the mitochondria, steroidogenic enzymes are inserted into the inner membrane with the bulk of the protein facing the matrix. They are not only important for steroid biosynthesis, their presence also affects mitochondrial morphology. Mitochondria undergo constant fission and fusion; they play important roles in energy production, apoptosis, and metabolism. Their defects often lead to human diseases. Mitochondrial cristae are usually lamellar in shape, but can also assume different shapes. Cristae in the mitochondria of steroidogenic cells are tubular-vesicular in shape. This cristae shape is also related to the degree of steroidogenic cell differentiation. Steroidogenic enzymes in the mitochondria appear to have a dual role in shaping the morphology of mitochondria and in steroid production.

Adrenal cortical and chromaffin stem cells: Is there a common progeny related to stress adaptation?

The adrenal gland is a highly plastic organ with the capacity to adapt the body homeostasis to different physiological needs. The existence of stem-like cells in the adrenal cortex has been revealed in many studies. Recently, we identified and characterized in mice a pool of glia-like multipotent Nestin-expressing progenitor cells, which contributes to the plasticity of the adrenal medulla. In addition, we found that these Nestin progenitors are actively involved in the stress response by giving rise to chromaffin cells. Interestingly, we also observed a Nestin-GFP-positive cell population located under the adrenal capsule and scattered through the cortex. In this article, we discuss the possibility of a common progenitor giving rise to subpopulations of cells both in the adrenal cortex and medulla, the isolation and characterization of this progenitor as well as its clinical potential in transplantation therapies and in pathophysiology.

Regulation of zonation and homeostasis in the adrenal cortex

The adult adrenal cortex is organized into concentric zones, each specialized to produce distinct steroid hormones. Cellular composition of the cortex is highly dynamic and subject to diverse signaling controls. Cortical homeostasis and regeneration rely on centripetal migration of steroidogenic cells from the outer to the inner cortex, which is accompanied by direct conversion of zona glomerulosa (zG) into zona fasciculata (zF) cells. Given the important impact of tissue structure and growth on steroidogenic function, it is essential to understand the mechanisms governing adrenal zonation and homeostasis. Towards this end, we review the distinctions between each zone by highlighting their morphological and ultra-structural features, discuss key signaling pathways influencing zonal identity, and evaluate current evidence for long-term self-renewing stem cells in the adult cortex. Finally, we review data supporting zG-to-zF transdifferentiation/direct conversion as a major mechanism of adult cortical renewal.

The hunt for a selective 17,20 lyase inhibitor; learning lessons from nature

Given prostate cancer is driven, in part, by its responsiveness to androgens, treatments historically employ methods for their removal from circulation. Approaches as crude as castration, and more recently blockade of androgen synthesis or receptor binding, are still of limited use long term, since other steroids of adrenal origin or tumor origin can supersede that role as the 'castration resistant' tumor re-emerges. Broader inhibition of steroidogenesis using relatively nonselective P450 inhibitors such as ketoconazole is not an alternative since a general disruption of steroid biosynthesis is neither safe nor effective. The recent emergence of drugs more selectively targeting CYP17 have been more effective, and yet extension of life has been on the scale of months rather than years. It is now becoming clear this shortcoming arises from the adaptive capabilities of many tumors to initiate local steroid synthesis and/or become responsive to novel early pathway adrenal steroids that are synthesized when lyase activity is not selectively blocked, and ACTH rises in the face of declining cortisol feedback. Abiraterone has been described as a lyase selective inhibitor, yet its use still requires co-administration of prednisone to suppress such a rise of ACTH and fall in cortisol. So is creation of a selective lyase inhibitor even possible? Can C19 steroid production be achieved without a prominent decline in cortisol and corresponding rise in ACTH? Decades of scientific study of CYP17 in humans and nonhuman primates, as well as nature's own experiments of gene mutations in humans, reveal 'true' or 'isolated' 17,20 lyase deficiency does quite selectively prevent C19 steroid biosynthesis whereas simple 17 hydroxylase deficiency also suppresses cortisol. We propose these known outcomes of natural mutations should be used to guide analysis of clinical trials and long term outcomes of CYP17 targeted drugs. In this review, we use that framework to re-evaluate the basic and clinical outcomes of many compounds being used or in development for treatment of castration resistant prostate cancer. Specifically, we include the nonselective drug ketoconazole, and then the CYP17 targeted drugs abiraterone, orteronel (TAK-700), galaterone (TOK-001), and seviteronel (VT-464). Using this framework, we can fully discriminate the clinical outcomes for ketoconazole, a drug with broad specificity, yet clinically ineffective, from that of abiraterone, the first CYP17 targeted therapy that is limited by its need for prednisone co-therapy. We also can identify potential next generation CYP17 targeted drugs now emerging that show signs of being far more 17,20 lyase selective. We conclude that a future for improved therapy without substantial cortisol decline, thus avoiding prednisone co-administration, seems possible at long last.

Functional Zonation of the Adult Mammalian Adrenal Cortex

The standard model of adrenocortical zonation holds that the three main zones, glomerulosa, fasciculata, and reticularis each have a distinct function, producing mineralocorticoids (in fact just aldosterone), glucocorticoids, and androgens respectively. Moreover, each zone has its specific mechanism of regulation, though ACTH has actions throughout. Finally, the cells of the cortex originate from a stem cell population in the outer cortex or capsule, and migrate centripetally, changing their phenotype as they progress through the zones. Recent progress in understanding the development of the gland and the distribution of steroidogenic enzymes, trophic hormone receptors, and other factors suggests that this model needs refinement. Firstly, proliferation can take place throughout the gland, and although the stem cells are certainly located in the periphery, zonal replenishment can take place within zones. Perhaps more importantly, neither the distribution of enzymes nor receptors suggest that the individual zones are necessarily autonomous in their production of steroid. This is particularly true of the glomerulosa, which does not seem to have the full suite of enzymes required for aldosterone biosynthesis. Nor, in the rat anyway, does it express MC2R to account for the response of aldosterone to ACTH. It is known that in development, recruitment of stem cells is stimulated by signals from within the glomerulosa. Furthermore, throughout the cortex local regulatory factors, including cytokines, catecholamines and the tissue renin-angiotensin system, modify and refine the effects of the systemic trophic factors. In these and other ways it more and more appears that the functions of the gland should be viewed as an integrated whole, greater than the sum of its component parts.

Pubertal development and regulation

Puberty marks the end of childhood and is a period when individuals undergo physiological and psychological changes to achieve sexual maturation and fertility. The hypothalamic-pituitary-gonadal axis controls puberty and reproduction and is tightly regulated by a complex network of excitatory and inhibitory factors. This axis is active in the embryonic and early postnatal stages of life and is subsequently restrained during childhood, and its reactivation culminates in puberty initiation. The mechanisms underlying this reactivation are not completely known. The age of puberty onset varies between individuals and the timing of puberty initiation is associated with several health outcomes in adult life. In this Series paper, we discuss pubertal markers, epidemiological trends of puberty initiation over time, and the mechanisms whereby genetic, metabolic, and other factors control secretion of gonadotropin-releasing hormone to determine initiation of puberty.

Mouse models of adrenocortical tumors

The molecular basis of the organogenesis, homeostasis, and tumorigenesis of the adrenal cortex has been the subject of intense study for many decades. Specifically, characterization of tumor predisposition syndromes with adrenocortical manifestations and molecular profiling of sporadic adrenocortical tumors have led to the discovery of key molecular pathways that promote pathological adrenal growth. However, given the observational nature of such studies, several important questions regarding the molecular pathogenesis of adrenocortical tumors have remained. This review will summarize naturally occurring and genetically engineered mouse models that have provided novel tools to explore the molecular and cellular underpinnings of adrenocortical tumors. New paradigms of cancer initiation, maintenance, and progression that have emerged from this work will be discussed.

Regulation of human (adrenal) androgen biosynthesis-New insights from novel throughput technology studies

Androgens are precursors for sex steroids and are predominantly produced in the human gonads and the adrenal cortex. They are important for intrauterine and postnatal sexual development and human reproduction. Although human androgen biosynthesis has been extensively studied in the past, exact mechanisms underlying the regulation of androgen production in health and disease remain vague. Here, the knowledge on human androgen biosynthesis and regulation is reviewed with a special focus on human adrenal androgen production and the hyperandrogenic disorder of polycystic ovary syndrome (PCOS). Since human androgen regulation is highly specific without a good animal model, most studies are performed on patients harboring inborn errors of androgen biosynthesis, on human biomaterials and human (tumor) cell models. In the past, most studies used a candidate gene approach while newer studies use high throughput technologies to identify novel regulators of androgen biosynthesis. Using genome wide association studies on cohorts of patients, novel PCOS candidate genes have been recently described. Variant 2 of the DENND1A gene was found overexpressed in PCOS theca cells and confirmed to enhance androgen production. Transcriptome profiling of dissected adrenal zones established a role for BMP4 in androgen synthesis. Similarly, transcriptome analysis of human adrenal NCI-H295 cells identified novel regulators of androgen production. Kinase p38α (MAPK14) was found to phosphorylate CYP17 for enhanced 17,20 lyase activity and RARB and ANGPTL1 were detected in novel networks regulating androgens. The discovery of novel players for androgen biosynthesis is of clinical significance as it provides targets for diagnostic and therapeutic use.