The mislabelling of deoxycorticosterone: making sense of corticosteroid structure and function

Mechanisms of ligand-mediated modulation of mineralocorticoid receptor signaling

The mineralocorticoid receptor plays a central role in homeostasis, mediating the regulation by aldosterone of epithelial sodium transport. In addition, it regulates a range of responses in other tissues where it is likely responding to both mineralocorticoids and glucocorticoids. Structural, functional and evolutionary studies have provided insights into the mechanisms of receptor activation by agonist ligands and how interactions within the domains of the mineralocorticoid receptor may modulate the response to individual ligands including the mechanisms of antagonism. This review will discuss the current understanding, including recent insights into these interactions, with implications for an emerging array of novel non-steroidal compounds targeting the mineralocorticoid receptor; and highlight their relevance to ligand- or tissue-specificity as well as their suitability as therapeutic agents.

A Patient with Partial 17α-Hydroxylase Deficiency Initially Diagnosed with Asherman Syndrome and Pheochromocytoma

This study present a case of a 49-year-old woman who suffered from resistant hypertension, hypokalemia, hypomenorrhea, and infertility. She was hospitalized 6 years earlier for hypomenorrhea and abdominal pain at the Xiamen Maternity and Child Health Hospital, where she was diagnosed with Asherman syndrome. During hospitalization, a computed tomography examination revealed an adrenal mass. She was referred to Xiamen University Affiliated Zhongshan Hospital for pheochromocytoma and underwent surgical resection of the left adrenal gland. The adrenal cortex adenoma was confirmed by pathological biopsy. Six years later, the patient also presented with hypertension and hypokalemia to our emergency department. A diagnosis of 17α-hydroxylase deficiency was established through the analysis of clinical and laboratory characteristics. The genetic analysis of CYP17A1 revealed compound heterozygous mutations, 1 of which was a mutation of c.1226 C>G, and the other c.297+2T>C.

Glucocorticoids with or without fludrocortisone in septic shock: a narrative review from a biochemical and molecular perspective

Two randomised controlled trials have reported a reduction in mortality when adjunctive hydrocortisone is administered in combination with fludrocortisone compared with placebo in septic shock. A third trial did not support this finding when hydrocortisone administered in combination with fludrocortisone was compared with hydrocortisone alone. The underlying mechanisms for this mortality benefit remain poorly understood. We review the clinical implications and potential mechanisms derived from laboratory and clinical data underlying the beneficial role of adjunctive fludrocortisone with hydrocortisone supplementation in septic shock. Factors including distinct biological effects of glucocorticoids and mineralocorticoids, tissue-specific and mineralocorticoid receptor-independent effects of mineralocorticoids, and differences in downstream signalling pathways between mineralocorticoid and glucocorticoid binding at the mineralocorticoid receptor could contribute to this interaction. Furthermore, pharmacokinetic and pharmacodynamic disparities exist between aldosterone and its synthetic counterpart fludrocortisone, potentially influencing their effects. Pending publication of well-designed, randomised controlled trials, a molecular perspective offers valuable insights and guidance to help inform clinical strategies.

Female red-winged blackbirds (Agelaius phoeniceus) do not alter nest site selection, maternal programming, or hormone-mediated maternal effects in response to perceived nest predation or brood parasitism risk

Predation or brood parasitism risks can change the behaviors and reproductive decisions in many parental animals. For oviparous species, mothers can mitigate their reproductive success in at least three ways: (1) by avoiding nest sites with high predation or parasitism risks, (2) through hormonal maternal effects that developmentally prime offspring for survival in risky environments, or (3) by investing less in reproduction when predation or parasitism risks are high. Here, we tested if perceived predation and parasitism risks can induce any of these behavioral or physiological responses by exposing female red-winged blackbirds (Agelaius phoeniceus) to playbacks of two major nest threats, a predator (Cooper's hawk, Accipiter cooperii) and an obligate brood parasite (brown-headed cowbird; Molothrus ater), as well as two controls (harmless Eastern meadowlark, Sturnella magna; and silence). We found that female blackbirds did not avoid nesting at sites treated with predator or brood parasite playbacks, nor were females more likely to abandon nesting attempts at these sites. Egg size and yolk hormone profiles, which are common proxies for maternal investment in oviparous species, were statistically similar across treatment sites. Instead, we found intraclutch variation in yolk steroid hormone profiles: concentrations of three progestogens (pregnanedione, 17α-hydroxypregnenolone, and deoxycorticosterone) and two androgens (testosterone and androstenedione) were higher in third-laid than first-laid eggs. Our study largely confirms previous findings of consistent intraclutch yolk hormone variation in this species, in birds in general, and in other oviparous lineages, but uniquely reports on several yolk steroid hormones largely overlooked in the literature on hormone-mediated maternal effects.

Mineralocorticoid Receptor Antagonists for Preventing Chronic Kidney Disease Progression: Current Evidence and Future Challenges

Regulation and action of the mineralocorticoid receptor (MR) have been the focus of intensive research over the past 80 years. Genetic and physiological/biochemical analysis revealed how MR and the steroid hormone aldosterone integrate the responses of distinct tubular cells in the face of environmental perturbations and how their dysregulation compromises fluid homeostasis. In addition to these roles, the accumulation of data also provided unequivocal evidence that MR is involved in the pathophysiology of kidney diseases. Experimental studies delineated the diverse pathological consequences of MR overactivity and uncovered the multiple mechanisms that result in enhanced MR signaling. In parallel, clinical studies consistently demonstrated that MR blockade reduces albuminuria in patients with chronic kidney disease. Moreover, recent large-scale clinical studies using finerenone have provided evidence that the non-steroidal MR antagonist can retard the kidney disease progression in diabetic patients. In this article, we review experimental data demonstrating the critical importance of MR in mediating renal injury as well as clinical studies providing evidence on the renoprotective effects of MR blockade. We also discuss areas of future investigation, which include the benefit of non-steroidal MR antagonists in non-diabetic kidney disease patients, the identification of surrogate markers for MR signaling in the kidney, and the search for key downstream mediators whereby MR blockade confers renoprotection. Insights into these questions would help maximize the benefit of MR blockade in subjects with kidney diseases.

Inter-Individual Variation in Anti-Parasitic Egg Rejection Behavior: A Test of the Maternal Investment Hypothesis

Hosts of avian brood parasites may reduce or forego the costs of caring for foreign young by rejecting parasitic eggs from the nest. Yet, many host species accept parasitic eggs and, even among rejecter species, some individuals go on to incubate and hatch them. The factors explaining the variation in egg rejection between species have received much theoretical and empirical attention, but the causes of intraspecific variation in different individuals’ propensity for accepting parasitic eggs are less well understood. Here we tested the maternal investment hypothesis, which predicts that hosts with costlier clutches will be more likely to reject parasitic eggs from their nest. We studied variation in the egg rejection responses of American robins (Turdus migratorius), a robust egg-rejecter host of the brood parasitic brown-headed cowbird (Molothrus ater), to 3D-printed cowbird-sized eggs which were painted dark blue, a color known to induce variable and repeatable egg rejection responses in individual robins. Costlier clutch investment was estimated by earlier laying date, larger clutch size, heavier unincubated yolk mass, and variable yolk steroid hormone concentrations. There was no statistical support for most of our predictions. However, we detected more concentrated and greater overall amount of deoxycorticosterone deposited in egg yolks of rejecters relative to acceptors, although this accounted for no more than 14% of variance in the data. Future work should test experimentally the potential physiological linkage between maternal egg yolk steroid investment and egg rejection propensity in this and other host species of avian brood parasites.

Mineralocorticoid Dysfunction during Critical Illness: A Review of the Evidence

The recent demonstration of the significant reduction in mortality in patients with septic shock treated with adjunctive glucocorticoids combined with fludrocortisone and the effectiveness of angiotensin II in treating vasodilatory shock have renewed interest in the role of the mineralocorticoid axis in critical illness. Glucocorticoids have variable interactions at the mineralocorticoid receptor. Similarly, mineralocorticoid receptor-aldosterone interactions differ from mineralocorticoid receptor-glucocorticoid interactions and predicate receptor-ligand interactions that differ with respect to cellular effects. Hyperreninemic hypoaldosteronism or selective hypoaldosteronism, an impaired adrenal response to increasing renin levels, occurs in a subgroup of hemodynamically unstable critically ill patients. The suggestion is that there is a defect at the level of the adrenal zona glomerulosa associated with a high mortality rate that may represent an adaptive response aimed at increasing cortisol levels. Furthermore, cross-talk exists between angiotensin II and aldosterone, which needs to be considered when employing therapeutic strategies.

Aspalathus linearis (Rooibos) - a functional food targeting cardiovascular disease

Increasing consumer bias toward natural products and the considerable wealth of indigenous knowledge has precipitated an upturn in market-driven research into potentially beneficial medicinal plants. In this context, Aspalathus linearis (Rooibos) has been identified to be a promising candidate which may impact cardiovascular disease (CVD), which is one of the most widely studied chronic diseases of modern times. Despite these efforts, ischemic heart disease remains the number one cause of mortality globally. Apart from genetic predisposition and other aetiological mechanisms specific to particular types of CVD, co-factors from interlinked systems contribute significantly to disease development and the severity of its clinical manifestation. The bioactivity of Rooibos is directed towards multiple therapeutic targets. Experimental data to date include antioxidant, anti-inflammatory and anti-diabetic effects, as well as modulatory effects in terms of the immune system, adrenal steroidogenesis and lipid metabolism. This review integrates relevant literature on the therapeutic potential of Rooibos in the context of CVD, which is currently the most common of non-communicable diseases. The therapeutic value of whole plant extracts versus isolated active ingredients are addressed, together with the potential for overdose or herb-drug interaction. The body of research undertaken to date clearly underlines the benefits of Rooibos as both preventative and complementary therapeutic functional food in the context of CVD.

Endothelial cell mineralocorticoid receptors oppose VEGF-induced gene expression and angiogenesis

Aldosterone is a key factor in adverse cardiovascular remodeling by acting on the mineralocorticoid receptor (MR) in different cell types. Endothelial MR activation mediates hypertrophy, inflammation and fibrosis. Cardiovascular remodeling is often accompanied by impaired angiogenesis, which is a risk factor for the development of heart failure. In this study, we evaluated the impact of MR in endothelial cells on angiogenesis. Deoxycorticosterone acetate (DOCA)-induced hypertension was associated with capillary rarefaction in the heart of WT mice but not of mice with cell type-specific MR deletion in endothelial cells. Consistently, endothelial MR deletion prevented the inhibitory effect of aldosterone on the capillarization of subcutaneously implanted silicon tubes and on capillary sprouting from aortic ring segments. We examined MR-dependent gene expression in cultured endothelial cells by RNA-seq and identified a cluster of differentially regulated genes related to angiogenesis. We found opposing effects on gene expression when comparing activation of the mineralocorticoid receptor in ECs to treatment with vascular endothelial growth factor (VEGF), a potent activator of angiogenesis. In conclusion, we demonstrate here that activation of endothelial cell MR impaired angiogenic capacity and lead to capillary rarefaction in a mouse model of MR-driven hypertension. MR activation opposed VEGF-induced gene expression leading to the dysregulation of angiogenesis-related gene networks in endothelial cells. Our findings underscore the pivotal role of endothelial cell MR in the pathophysiology of hypertension and related heart disease.

MicroRNA-21 ablation exacerbates aldosterone-mediated cardiac injury, remodeling, and dysfunction

Primary aldosteronism is characterized by excess aldosterone secretion by the adrenal gland independent of the renin-angiotensin system and accounts for ~10% of hypertensive patients. Excess aldosterone causes cardiac hypertrophy, fibrosis, inflammation, and hypertension. The molecular mechanisms that trigger the onset and progression of aldosterone-mediated cardiac injury remain incompletely understood. MicroRNAs (miRNAs) are endogenous, small, noncoding RNAs that have been implicated in multiple cardiac pathologies; however, their regulation and role in aldosterone-mediated cardiac injury and dysfunction remains mostly unknown. We previously reported that microRNA-21 (miR-21) is the most upregulated miRNA by excess aldosterone in the left ventricle in a rat experimental model of primary aldosteronism. To elucidate the role of miR-21 in aldosterone-mediated cardiac injury and dysfunction, miR-21 knockout mice and their wild-type littermates were treated with aldosterone infusion and salt in the drinking water for 2 or 8 wk. miR-21 genetic ablation exacerbated aldosterone/salt-mediated cardiac hypertrophy and cardiomyocyte cross-sectional area. Furthermore, miR-21 genetic ablation increased the cardiac expression of fibrosis and inflammation markers and fetal gene program. miR-21 genetic ablation increased aldosterone/salt-mediated cardiac dysfunction but did not affect aldosterone/salt-mediated hypertension. miR-21 target gene Sprouty 2 may be implicated in the cardiac effects of miR-21 genetic ablation. Our study shows that miR-21 genetic ablation exacerbates aldosterone/salt-mediated cardiac hypertrophy, injury, and dysfunction blood pressure independently. These results suggest that miR-21 plays a protective role in the cardiac pathology triggered by excess aldosterone. Furthermore, miR-21 supplementation may be a novel therapeutic approach to abolish or mitigate excess aldosterone-mediated cardiovascular deleterious effects in primary aldosteronism.

Lesion of the OVLT markedly attenuates chronic DOCA-salt hypertension in rats

Lesions of the anteroventral third ventricle (AV3V region) are known to prevent many forms of experimental hypertension, including mineralocorticoid [deoxycorticosterone acetate (DOCA)-salt] hypertension in the rat. However, AV3V lesions include the organum vasculosum of the lamina terminalis (OVLT), portions of the median preoptic nucleus, and efferent fibers from the subfornical organ (SFO), thereby limiting the ability to define the individual contribution of these structures to the prevention of experimental hypertension. Having previously reported that the SFO does not play a significant role in the development of DOCA-salt hypertension, the present study was designed to test the hypothesis that the OVLT is necessary for DOCA-salt hypertension in the rat. In uninephrectomized OVLT-lesioned (OVLTx; n = 6) and sham-operated ( n = 4) Sprague-Dawley rats consuming a 0.1% NaCl diet and 0.9% NaCl drinking solution, 24-h mean arterial pressure (MAP) was recorded telemetrically 5 days before and 21 days after DOCA implantation (100 mg sc per rat). No differences in control MAP were observed between groups. The chronic pressor response to DOCA was attenuated in OVLTx rats such that MAP increased to 133 ± 3 mmHg in sham-operated rats by day 21 of DOCA compared with 120 ± 4 mmHg (means ± SE) in OVLTx rats. These results support the hypothesis that the OVLT is an important brain site of action for the pathogenesis of DOCA-salt hypertension in the rat.

Mineralocorticoid hypertension and hypokalaemia induced by posaconazole

We describe severe hypokalaemia and hypertension due to a mineralocorticoid effect in a patient with myelodysplastic syndrome taking posaconazole as antifungal prophylaxis. Two distinct mechanisms due to posaconazole are identified: inhibition of 11β hydroxylase leading to the accumulation of the mineralocorticoid hormone 11-deoxycorticosterone (DOC) and secondly, inhibition of 11β hydroxysteroid dehydrogenase type 2 (11βHSD2), as demonstrated by an elevated serum cortisol-to-cortisone ratio. The effects were ameliorated by spironolactone. We also suggest that posaconazole may cause cortisol insufficiency. Patients taking posaconazole should therefore be monitored for hypokalaemia, hypertension and symptoms of hypocortisolaemia, at the onset of treatment and on a monthly basis. Treatment with mineralocorticoid antagonists (spironolactone or eplerenone), supplementation of glucocorticoids (e.g. hydrocortisone) or dose reduction or cessation of posaconazole should all be considered as management strategies.

Usefulness of Simultaneous Measurement of Plasma Steroids, Including Precursors, for the Evaluation of Drug Effects on Adrenal Steroidogenesis in Rats

The aim of this study was to evaluate the usefulness of simultaneous measurement of plasma steroids, including precursors, for the evaluation of drug effects on adrenal steroidogenesis in vivo. Plasma concentrations of corticosterone and its precursors were examined in rats dosed with compounds that affect adrenal steroidogenesis via different modes of action as well as the relationships of the changes with blood chemistry and adrenal histopathology. Male rats were dosed with tricresyl phosphate, aminoglutethimide, trilostane (TRL), metyrapone (MET), ketoconazole (KET), or mifepristone for 7 days. In the TRL, MET, and KET groups, precursor levels were markedly increased, while there were no significant changes in the corticosterone level, suggesting that the precursors are more sensitive biomarkers to detect the effect on adrenal steroidogenesis. Also, the precursors with increased levels were those that are normally metabolized by the inhibited enzymes, reflecting the modes of action of the compounds. In addition, different patterns of changes were observed in blood chemistry and histopathology, supporting the mechanism suggested by the steroid changes. These results show that simultaneous measurement of plasma steroids, including precursors, can be a valuable method to sensitively evaluate drug effects on adrenal steroidogenesis and to investigate the underlying mechanisms.

Sutherlandia frutescens modulates adrenal hormone biosynthesis, acts as a selective glucocorticoid receptor agonist (SEGRA) and displays anti-mineralocorticoid properties

ETHNOPHARMACOLOGICAL RELEVANCE

Sutherlandia frutescens is a traditional African medicinal plant used in the treatment of stress and anxiety, while also exhibiting anti-inflammatory properties.

AIM OF STUDY

The study aimed at linking anti-stress and anti-inflammatory properties of S. frutescens to its influence on glucocorticoid biosynthesis and the inflammatory response via steroid receptor interaction.

MATERIALS AND METHODS

The influence of S. frutescens extracts and sutherlandioside B (SUB),10 and 30µM, on key steroidogenic enzymes was assayed in COS-1 cells. Effects were also assayed on basal and stimulated hormone levels in the adrenal H295R cell model. Agonist activity for transactivation and transrepression of the extract and SUB with the glucocorticoid- (GR) and mineralocorticoid receptor (MR) was subsequently investigated.

RESULTS

Inhibitory effects of the extract towards progesterone conversion by CYP17A1 and CYP21A2 were significant. SUB inhibited CYP17A1 and 3β-HSD2, while not affecting CYP21A2. In H295R cells, SUB decreased cortisol and androgen precursors significantly. The extract decreased total steroid production (basal and stimulated) with cortisol and its precursor, deoxycortisol, together with mineralocorticoid metabolites significantly decreased under forskolin stimulated conditions. S. frutescens extracts and SUB repressed NF-κB-driven gene expression without activating GRE-driven gene expression and while neither activated MR mediated gene transcription, both antagonized the effects of aldosterone via the MR.

CONCLUSION

Data provide evidence linking anti-stress, anti-inflammatory and anti-hypertensive properties of S. frutescens to inhibition of steroidogenic enzymes and modulation of adrenal hormone biosynthesis. Findings suggesting S. frutescens and SUB exhibit dissociated glucocorticoid characteristics underline potential therapeutic applications in the treatment of inflammation and hypertension.

Clinical perspectives in congenital adrenal hyperplasia due to 11β-hydroxylase deficiency

Congenital adrenal hyperplasia due to 11 beta-hydroxylase deficiency is a rare autosomal recessive genetic disorder. It is caused by reduced or absent activity of 11β-hydroxylase (CYP11B1) enzyme and the resultant defects in adrenal steroidogenesis. The most common clinical features of 11 beta-hydroxylase deficiency are ambiguous genitalia, accelerated skeletal maturation and resultant short stature, peripheral precocious puberty and hyporeninemic hypokalemic hypertension. The biochemical diagnosis is based on raised serum 11-deoxycortisol and 11-deoxycorticosterone levels together with increased adrenal androgens. More than 100 mutations in CYP11B1 gene have been reported to date. The level of in-vivo activity of CYP11B1 relates to the degree of severity of 11 beta-hydroxylase deficiency. Clinical management of 11 beta-hydroxylase deficiency can pose a challenge to maintain adequate glucocorticoid dosing to suppress adrenal androgen excess while avoiding glucocorticoid-induced side effects. The long-term outcomes of clinical and surgical management are not well studied. This review article aims to collate the current available data about 11 beta-hydroxylase deficiency and its management.

Third-generation Mineralocorticoid Receptor Antagonists: Why Do We Need a Fourth?

The first mineralocorticoid receptor (MR) antagonist, spironolactone, was developed almost 60 years ago to treat primary aldosteronism and pathological edema. Its use waned in part because of its lack of selectivity. Subsequently, knowledge of the scope of MR function was expanded along with clinical evidence of the therapeutic importance of MR antagonists to prevent the ravages of inappropriate MR activation. Forty-two years elapsed between the first and MR-selective second generation of MR antagonists. Fifteen years later, despite serious shortcomings of the existing antagonists, a third-generation antagonist has yet to be marketed. Progress has been slowed by the lack of appreciation of the large variety of cell types that express the MR and its diverse cell-type-specific actions, and also its unique complex interaction actions at the molecular level. New MR antagonists should preferentially target the inflammatory and fibrotic effects of MR and perhaps its excitatory effects on sympathetic nervous system, but not the renal tubular epithelium or neurons of the cortex and hippocampus. This review briefly describes efforts to develop a third-generation MR antagonist and why fourth generation antagonists and selective agonists based on structural determinants of tissue and ligand-specific MR activation should be contemplated.

Mineralocorticoid Receptor (MR) trans-Activation of Inflammatory AP-1 Signaling: DEPENDENCE ON DNA SEQUENCE, MR CONFORMATION, AND AP-1 FAMILY MEMBER EXPRESSION

Glucocorticoids are commonly used to treat inflammatory disorders. The glucocorticoid receptor (GR) can tether to inflammatory transcription factor complexes, such as NFκB and AP-1, and trans-repress the transcription of cytokines, chemokines, and adhesion molecules. In contrast, aldosterone and the mineralocorticoid receptor (MR) primarily promote cardiovascular inflammation by incompletely understood mechanisms. Although MR has been shown to weakly repress NFκB, its role in modulating AP-1 has not been established. Here, the effects of GR and MR on NFκB and AP-1 signaling were directly compared using a variety of ligands, two different AP-1 consensus sequences, GR and MR DNA-binding domain mutants, and siRNA knockdown or overexpression of core AP-1 family members. Both GR and MR repressed an NFκB reporter without influencing p65 or p50 binding to DNA. Likewise, neither GR nor MR affected AP-1 binding, but repression or activation of AP-1 reporters occurred in a ligand-, AP-1 consensus sequence-, and AP-1 family member-specific manner. Notably, aldosterone interactions with both GR and MR demonstrated a potential to activate AP-1. DNA-binding domain mutations that eliminated the ability of GR and MR to cis-activate a hormone response element-driven reporter variably affected the strength and polarity of these responses. Importantly, MR modulation of NFκB and AP-1 signaling was consistent with a trans-mechanism, and AP-1 effects were confirmed for specific gene targets in primary human cells. Steroid nuclear receptor trans-effects on inflammatory signaling are context-dependent and influenced by nuclear receptor conformation, DNA sequence, and the expression of heterologous binding partners. Aldosterone activation of AP-1 may contribute to its proinflammatory effects in the vasculature.

Interaction between the trout mineralocorticoid and glucocorticoid receptors in vitro

The salmonid corticosteroid receptors (CRs), glucocorticoid receptors 1 and 2 (GR1 and GR2) and the mineralocorticoid receptor (MR) share a high degree of homology with regard to structure, ligand- and DNA response element-binding, and cellular co-localization. Typically, these nuclear hormone receptors homodimerize to confer transcriptional activation of target genes, but a few studies using mammalian receptors suggest some degree of heterodimerization. We observed that the trout MR confers a several fold lower transcriptional activity compared to the trout GRs. This made us question the functional relevance of the MR when this receptor is located in the same cells as the GRs and activated by cortisol. A series of co-transfection experiments using different glucocorticoid response elements (GREs) containing promoter-reporter constructs were carried out to investigate any possible interaction between the piscine CRs. Co-transfection of the GRs with the MR significantly reduced the total transcriptional activity even at low MR levels, suggesting interaction between these receptors. Co-transfection of GR1 or GR2 with the MR did not affect the subcellular localization of the GRs, and the MR-mediated inhibition seemed to be independent of specific activation or inhibition of the MR. Site-directed mutagenesis of the DNA-binding domain and dimerization interface of the MR showed that the inhibition was dependent on DNA binding but not necessarily on dimerization ability. Thus, we suggest that the interaction between MR and the GRs may regulate the cortisol response in cell types where the receptors co-localize and propose a dominant-negative role for the MR in cortisol-mediated transcriptional activity.

Steroid profiling reveals widespread local regulation of glucocorticoid levels during mouse development

Glucocorticoids (GCs) are produced by the adrenal glands and circulate in the blood to coordinate organismal physiology. In addition, different tissues may independently regulate their local GC levels via local GC synthesis. Here, we find that in the mouse, endogenous GCs show tissue-specific developmental patterns, rather than mirroring GCs in the blood. Using solid-phase extraction, HPLC, and specific immunoassays, we quantified endogenous steroids and found that in tissues of female and male mice, (1) local GC levels can be much higher than systemic GC levels, (2) local GCs follow age-related patterns different from those of systemic GCs, and (3) local GCs have identities different from those of systemic GCs. For example, whereas corticosterone is the predominant circulating adrenal GC in mice, high concentrations of cortisol were measured in neonatal thymus, bone marrow, and heart. The presence of cortisol was confirmed with liquid chromatography-tandem mass spectrometry. In addition, gene expression of steroidogenic enzymes was detected across multiple tissues, consistent with local GC production. Our results demonstrate that local GCs can differ from GCs in circulating blood. This finding suggests that steroids are widely used as local (paracrine or autocrine) signals, in addition to their classic role as systemic (endocrine) signals. Local GC regulation may even be the norm, rather than the exception, especially during development.

Brain mineralocorticoid receptors in cognition and cardiovascular homeostasis

Mineralocorticoid receptors (MR) mediate diverse functions supporting osmotic and hemodynamic homeostasis, response to injury and inflammation, and neuronal changes required for learning and memory. Inappropriate MR activation in kidneys, heart, vessels, and brain hemodynamic control centers results in cardiovascular and renal pathology and hypertension. MR binds aldosterone, cortisol and corticosterone with similar affinity, while the glucocorticoid receptor (GR) has less affinity for cortisol and corticosterone. As glucocorticoids are more abundant than aldosterone, aldosterone activates MR in cells co-expressing enzymes with 11β-hydroxydehydrogenase activity to inactivate them. MR and GR co-expressed in the same cell interact at the molecular and functional level and these functions may be complementary or opposing depending on the cell type. Thus the balance between MR and GR expression and activation is crucial for normal function. Where 11β-hydroxydehydrogenase 2 (11β-HSD2) that inactivates cortisol and corticosterone in aldosterone target cells of the kidney and nucleus tractus solitarius (NTS) is not expressed, as in most neurons, MR are activated at basal glucocorticoid concentrations, GR at stress concentrations. An exception may be pre-autonomic neurons of the PVN which express MR and 11β-HSD1 in the absence of hexose-6-phosphate dehydrogenase required to generate the requisite cofactor for reductase activity, thus it acts as a dehydrogenase. MR antagonists, valuable adjuncts to the treatment of cardiovascular disease, also inhibit MR in the brain that are crucial for memory formation and exacerbate detrimental effects of excessive GR activation on cognition and mood. 11β-HSD1 inhibitors combat metabolic and cognitive diseases related to glucocorticoid excess, but may exacerbate MR action where 11β-HSD1 acts as a dehydrogenase, while non-selective 11β-HSD1&2 inhibitors cause injurious disruption of MR hemodynamic control. MR functions in the brain are multifaceted and optimal MR:GR activity is crucial. Therefore selectively targeting down-stream effectors of MR specific actions may be a better therapeutic goal.

Taenia solium tapeworms synthesize corticosteroids and sex steroids in vitro

Cysticercosis is a disease caused by the larval stage of Taenia solium cestodes that belongs to the family Taeniidae that affects a number of hosts including humans. Taeniids tapeworms are hermaphroditic organisms that have reproductive units called proglottids that gradually mature to develop testis and ovaries. Cysticerci, the larval stage of these parasites synthesize steroids. To our knowledge there is no information about the capacity of T. solium tapeworms to metabolize progesterone or other precursors to steroid hormones. Therefore, the aim of this paper was to investigate if T. solium tapeworms were able to transform steroid precursors to corticosteroids and sex steroids. T. solium tapeworms were recovered from the intestine of golden hamsters that had been orally infected with cysticerci. The worms were cultured in the presence of tritiated progesterone or androstenedione. At the end of the experiments the culture media were analyzed by thin layer chromatography. The experiments described here showed that small amounts of testosterone were synthesized from (3)H-progesterone by complete or segmented tapeworms whereas the incubation of segmented tapeworms with (3)H-androstenedione, instead of (3)H-progesterone, improved their capacity to synthesize testosterone. In addition, the incubation of the parasites with (3)H-progesterone yielded corticosteroids, mainly deoxicorticosterone (DOC) and 11-deoxicortisol. In summary, the results described here, demonstrate that T. solium tapeworms synthesize corticosteroid and sex steroid like metabolites. The capacity of T. solium tapeworms to synthesize steroid hormones may contribute to the physiological functions of the parasite and also to their interaction with the host.

Adrenal steroid hormones and ethanol self-administration in male rhesus macaques

RATIONALE

Hypothalamic-pituitary-adrenal (HPA) axis hormones have neuroactive metabolites with receptor activity similar to ethanol.

OBJECTIVES

The present study related HPA hormones in naïve monkeys to ethanol self-administration.

METHODS

Morning plasma adrenocorticotropic hormone (ACTH), cortisol, deoxycorticosterone (DOC), aldosterone, and dehydroepiandrosterone-sulfate (DHEA-S) were measured longitudinally in male rhesus macaques (Macaca mulatta) induced to drink ethanol followed by access to ethanol (4 % w/v, in water) and water 22 h/day for 12 months.

RESULTS

During ethanol access, DOC increased among non-heavy (average intake over 12 months ≤3.0 g/kg/day, n = 23) but not among heavy drinkers (>3.0 g/kg/day, n = 9); aldosterone was greater among heavy drinkers after 6 months. The ratio of DOC/aldosterone decreased only among heavy drinkers after 6 or12 months of ethanol self-administration. ACTH only correlated significantly with DHEA-S, the ratio of cortisol/DHEA-S and DOC after the onset of ethanol access, the former two just in heavy drinkers. Baseline hormones did not predict subsequent ethanol intake over 12 months, but baseline DOC correlated with average blood-ethanol concentrations (BECs), among all monkeys and heavy drinkers as a group. During ethanol access, aldosterone and DOC correlated and tended to correlate, respectively, with 12-month average ethanol intake.

CONCLUSIONS

Ethanol self-administration lowered ACTH and selectively altered its adrenocortical regulation. Mineralocorticoids may compensate for adrenocortical adaptation among heavy drinkers and balance fluid homeostasis. As DOC was uniquely predictive of future BEC and not water intake, to the exclusion of aldosterone, GABAergic neuroactive metabolites of DOC may be risk factors for binge drinking to intoxication.

The multifaceted mineralocorticoid receptor

The primary adrenal cortical steroid hormones, aldosterone, and the glucocorticoids cortisol and corticosterone, act through the structurally similar mineralocorticoid (MR) and glucocorticoid receptors (GRs). Aldosterone is crucial for fluid, electrolyte, and hemodynamic homeostasis and tissue repair; the significantly more abundant glucocorticoids are indispensable for energy homeostasis, appropriate responses to stress, and limiting inflammation. Steroid receptors initiate gene transcription for proteins that effect their actions as well as rapid non-genomic effects through classical cell signaling pathways. GR and MR are expressed in many tissues types, often in the same cells, where they interact at molecular and functional levels, at times in synergy, others in opposition. Thus the appropriate balance of MR and GR activation is crucial for homeostasis. MR has the same binding affinity for aldosterone, cortisol, and corticosterone. Glucocorticoids activate MR in most tissues at basal levels and GR at stress levels. Inactivation of cortisol and corticosterone by 11β-HSD2 allows aldosterone to activate MR within aldosterone target cells and limits activation of the GR. Under most conditions, 11β-HSD1 acts as a reductase and activates cortisol/corticosterone, amplifying circulating levels. 11β-HSD1 and MR antagonists mitigate inappropriate activation of MR under conditions of oxidative stress that contributes to the pathophysiology of the cardiometabolic syndrome; however, MR antagonists decrease normal MR/GR functional interactions, a particular concern for neurons mediating cognition, memory, and affect.

Analysis of 17 α-hydroxyprogesterone in bloodspots by liquid chromatography tandem mass spectrometry

Background

Monitoring of treatment for patients diagnosed with congenital adrenal hyperplasia (CAH) can be performed by measuring the concentration of 17α-hydroxyprogesterone (17OHP) in bloodspots collected on filter papers. A method is described here for measuring 17OHP by liquid chromatography tandem mass spectrometry (LCMSMS).

Methods

17OHP was extracted by liquid–liquid extraction and analysed by LCMSMS. The method was validated for sensitivity, specificity, linearity, recovery, ion suppression, precision and bias.

Results

The standard curve was linear from 0 to 400 nmol/L. Intra-assay %CVs were <10 and inter-assay %CVs were <15 over the range 10–200 nmol/L. Limit of quantitation was 6 nmol/L. No ion suppression was detected. The only interfering compound detected was deoxycorticosterone, an intermediate steroid with the same molecular weight as 17α-hydroxyprogesterone. The method was more accurate and precise than an existing radioimmunoassay. There was poor correlation between the two assays.

Conclusions

We have developed a sensitive and specific assay suitable for quantitation of 17OHP in bloodspots. This method performs better than radioimmunoassay and allows smaller samples to be used.

How glucocorticoid receptors modulate the activity of other transcription factors: a scope beyond tethering

The activity of the glucocorticoid receptor (GR), a nuclear receptor transcription factor belonging to subclass 3C of the steroid/thyroid hormone receptor superfamily, is typically triggered by glucocorticoid hormones. Apart from driving gene transcription via binding onto glucocorticoid response elements in regulatory regions of particular target genes, GR can also inhibit gene expression via transrepression, a mechanism largely based on protein:protein interactions. Hereby GR can influence the activity of other transcription factors, without contacting DNA itself. GR is known to inhibit the activity of a growing list of immune-regulating transcription factors. Hence, GCs still rule the clinic for treatments of inflammatory disorders, notwithstanding concomitant deleterious side effects. Although patience is a virtue when it comes to deciphering the many mechanisms GR uses to influence various signaling pathways, the current review is testimony of the fact that groundbreaking mechanistic work has been accumulating over the past years and steadily continues to grow.

Addiction and the adrenal cortex

Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion.