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The mineralocorticoid receptor (MR/NR3C2) is a member of the family of steroid receptors (SR) which also includes the estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR) and glucocorticoid receptor (GR). They function primarily as nuclear receptors to regulate gene expression. While the other steroid hormone receptors are known to play important roles in the pathogenesis and progression of many cancers, relatively little is understood about the role of MR in cancer biology. This review focuses on examining new insights into the potential roles and mechanisms of action of MR in cancers. • The mineralocorticoid receptor (MR) is an essential regulator of salt homeostasis. • We review the evidence for a role of MR in cancer development and progression. • MR expression is frequently disrupted in cancer. • Decreased expression of MR is a marker of poor outcome in several cancer types. • MR is implicated in regulation of a range of cancer associated processes. [ABSTRACT FROM AUTHOR]

There is growing evidence indicating that mineralocorticoid receptor (MR) expression influences a wide variety of functions in metabolic and immune response. The present study explored if antagonism of the MR reduces neuroinflammation in the spinal cord of mice with experimental autoimmune encephalomyelitis (EAE). Eplerenone (EPLE) (100 mg/kg dissolved in 30% 2-hydroxypropyl-β-cyclodextrin) was administered intraperitoneally (i.p.) daily from EAE induction (day 0) until sacrificed on day 17 post-induction. The MR blocker (a) significantly decreased the inflammatory parameters TLR4, MYD88, IL-1β, and iNOS mRNAs; (b) attenuated HMGB1, NLRP3, TGF-β mRNAs, microglia, and aquaporin4 immunoreaction without modifying GFAP. Serum IL-1β was also decreased in the EAE+EPLE group. Moreover, EPLE treatment prevented demyelination and improved clinical signs of EAE mice. Interestingly, MR was decreased and GR remained unchanged in EAE mice while EPLE treatment restored MR expression, suggesting that a dysbalanced MR/GR was associated with the development of neuroinflammation. Our results indicated that MR blockage with EPLE attenuated inflammation-related spinal cord pathology in the EAE mouse model of Multiple Sclerosis, supporting a novel therapeutic approach for immune-related diseases. ● EAE mice show high levels of proinflammatory markers in the spinal cord. ● Neuroinflammation associates with abnormal expression of the mineralocoricoid receptor (MR). ● Eplerenone, an antagonist of the MR reduces spinal cord inflammation. ● Eplerenone enhances myelination and motor performance of EAE mice. ● Restoration of MR/glucocorticoid receptor balance may be involved in Eplerenone effects. [ABSTRACT FROM AUTHOR]

The receptors and signaling pathways for nongenomic effects of aldosterone (Aldo) on the proximal Na + /H + exchanger are still unknown; therefore, the aim of this study was to investigate the mineralocorticoid receptor (MR) and/or glucocorticoid receptor (GR) participation in rapid Aldo effects on NHE1 (basolateral Na + /H + exchanger isoform) and cytosolic calcium concentration ([Ca 2+ ] i ). In addition, phospholipase C (PLC), protein kinase C (PKC), and mitogen-activated protein kinase kinase (MEK) involvement in signaling pathways of such effects was evaluated, using immortalized proximal tubule cells of rat (IRPTC) as an experimental model. MR and GR expression was investigated using reverse transcription polymerase chain reaction and immunoblotting. The intracellular pH recovery rate (after acid loading) and [Ca 2+ ] i were determined by the probes BCECF-AM and FURA 2-AM, respectively. Aldo (10 −12  M) promoted a moderate increase in [Ca 2+ ] i and stimulation of NHE1, whereas Aldo (10 −6  M) greatly increased the [Ca 2+ ] i , but inhibited the NHE1. BAPTA-AM (a calcium chelator), GR antagonism and inhibition of PLC, PKC and MEK pathway abolished the biphasic and dose-dependent effect of Aldo on NHE1 and decreased the [Ca 2+ ] i ; whereas MR do not appear to participate in this rapid signaling in IRPTC cells. The reduction of GR content, by gene silencing, abolished the Aldo effect on NHE1, in low concentration, confirming the importance of this receptor in the rapid modulation of proximal sodium and hydrogen transports. [ABSTRACT FROM AUTHOR]

Lampreys are jawless fish that evolved about 550 million years ago at the base of the vertebrate line. Modern lampreys contain a corticoid receptor (CR), the common ancestor of the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), which first appear in cartilaginous fish, such as sharks. Until recently, 344 amino acids at the amino terminus of adult lamprey CR were not present in the lamprey CR sequence in GenBank. A search of the recently sequenced lamprey germline genome identified two CR sequences, CR1 and CR2, containing the 344 previously un-identified amino acids. CR1 also contains a novel four amino acid insertion in the DNA-binding domain (DBD). We studied corticosteroid and progesterone activation of CR1 and CR2 and found their strongest response was to 11-deoxycorticosterone and 11-deoxycortisol, the two circulating corticosteroids in lamprey. Based on steroid specificity, both CRs are close to elephant shark MR and distant from elephant shark GR. HEK293 cells that were transfected with full-length CR1 or CR2 and the MMTV promoter have about 3-fold higher steroid-mediated activation compared to HEK293 cells transfected with these CRs and the TAT3 promoter. Deletion of the amino-terminal domain (NTD) of lamprey CR1 and CR2 to form truncated CRs decreased transcriptional activation by about 70% in HEK293 cells that were transfected with MMTV, but increased transcription by about 6-fold in cells transfected with TAT3. This indicated that the promoter has an important effect on NTD regulation of transcriptional activation of the CR by steroids. Our results also indicate that the entire lamprey CR sequence is needed for an accurate determination of steroid-mediated transcription. • Lamprey contains two corticoid receptors (CRs), CR1 and CR2. • The N-terminal Domain: an allosteric regulator of transcription for both CRs. • 11-deoxycortisol and 11-deoxycorticosterone activate both CRs. • Lamprey CR is closer to elephant shark MR than to elephant shark GR. [ABSTRACT FROM AUTHOR]

Recent studies suggest that progesterone may possess anti-tumorigenic properties. However, a growth-modulatory role of progestins in human cancer cells remains obscure. With the discovery of a new class of membrane progesterone receptors (mPRs) belonging to the progestin and adipoQ receptor gene family, it becomes important to study the effect of this hormone on proliferation of tumor cells that do not express classical nuclear progesterone receptors (nPRs). To identify a cell line expressing high levels of mPRs and lacking nPRs, we examined mRNA levels of nPRs and three forms of mPRs in sixteen human tumor cell lines of different origin. High expression of mPR mRNA has been found in pancreatic adenocarcinoma BxPC3 cells, while nPR mRNA has not been detected in these cells. Western blot analysis confirmed these findings at the protein level. We revealed specific binding of labeled progesterone in these cells with affinity constant similar to that of human mPR expressed in yeast cells. Progesterone at high concentration of 20 μM significantly reduced the mRNA levels of proliferation markers Ki67 and PCNA, as well as of cyclin D1, and increased the mRNA levels of cyclin dependent kinase inhibitors p21 and p27. Progesterone (1 μM and 20 μM) significantly inhibited proliferative activity of BxPC3 cells. These results point to anti-proliferative effects of the progesterone high concentrations on BxPC3 cells and suggest that activation of mPRs may mediate this action. Our data are a starting point for further investigations regarding the application of progesterone in pancreatic cancer. [ABSTRACT FROM AUTHOR]

Spironolactone and its major metabolite canrenone are potent mineralocorticoid receptor antagonists and are, therefore, applied as drugs for the treatment of primary aldosteronism and essential hypertension. We report that both compounds can be converted by the purified adrenocortical cytochromes P450 CYP11B1 and CYP11B2, while no conversion of the selective mineralocorticoid receptor antagonist eplerenone was observed. As their natural function, CYP11B1 and CYP11B2 carry out the final steps in the biosynthesis of gluco- and mineralocorticoids. Dissociation constants for the new exogenous substrates were determined by a spectroscopic binding assay and demonstrated to be comparable to those of the natural substrates, 11-deoxycortisol and 11-deoxycorticosterone. Metabolites were produced at preparative scale with a CYP11B2-dependent Escherichia coli whole-cell system and purified by HPLC. Using NMR spectroscopy, the metabolites of spironolactone were identified as 11β-OH-spironolactone, 18-OH-spironolactone and 19-OH-spironolactone. Canrenone was converted to 11β-OH-canrenone, 18-OH-canrenone as well as to the CYP11B2-specific product 11β,18-diOH-canrenone. Therefore, a contribution of CYP11B1 and CYP11B2 to the biotransformation of drugs should be taken into account and the metabolites should be tested for their potential toxic and pharmacological effects. A mineralocorticoid receptor transactivation assay in antagonist mode revealed 11β-OH-spironolactone as pharmaceutically active metabolite, whereas all other hydroxylation products negate the antagonist properties of spironolactone and canrenone. Thus, human CYP11B1 and CYP11B2 turned out to metabolize steroid-based drugs additionally to the liver-dependent biotransformation of drugs. Compared with the action of the parental drug, changed properties of the metabolites at the target site have been observed. [ABSTRACT FROM AUTHOR]

Mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) are descended from a common ancestral corticoid receptor. The basis for specificities of human MR for aldosterone and human GR for glucocorticoids, such as cortisol, bearing 17α-hydroxyl-groups, is incompletely understood. Differences in MR at S843 and L848 and GR at the corresponding P637 and Q642 have been proposed as important in their different responses to glucocorticoids with 17α-hydroxyl-groups. We investigated the impact of these residues on binding affinity (K i ) and transcriptional activation (EC 50 ) of mutants MR-S843P, MR-L848Q and MR-S843P/L848Q and mutants GR-P637S, GR-Q642L and GR-P637S/Q642L in the presence of different corticosteroids. Aldosterone, cortisol and corticosterone had similar affinities for wild-type MR and all mutants, while dexamethasone had increased affinity for the three mutants. However, transactivation of MR-S843P and MR-S843P/L848Q by all four steroids was significantly lower than for wild-type MR. In contrast, transactivation of MR-L848Q tended to be 3-fold higher for cortisol and corticosterone and increased 7-fold for dexamethasone, indicating that MR-L848Q has an increased response to glucocorticoids, while retaining a strong response to aldosterone. Compared to wild-type GR, GR-P637S and GR-Q642L had increased affinities and significantly increased transcriptional activity with aldosterone and corticosterone, and GR-P637S had similar transcriptional activity with cortisol and dexamethasone, while GR-Q642L and GR-P637S/Q642L had a significant decrease in transcriptional activity with cortisol and dexamethasone. 3D-models of these MR and GR mutants revealed that dexamethasone and aldosterone, respectively, fit nicely into the steroid-binding pocket, consistent with the affinity of dexamethasone for MR mutants and aldosterone for GR mutants. [ABSTRACT FROM AUTHOR]

Normal pressure hydrocephalus (NPH) is a treatable neurological disorder affecting elderly people with the prevalence increasing with age. NPH is caused by abnormal cerebrospinal fluid (CSF) reabsorption and manifested as a balance impairment, urinary incontinence and dementia development. These symptoms are potentially reversible if recognized early. Diagnosis of NPH is difficult and can be easily mistaken for other neurodegenerative disorders, which makes NPH one of the major misdiagnosed diseases worldwide. The aim of the study was to find out the appropriate combination of indicators, based on CSF steroids, which would contribute to a clearer NPH diagnosis. The levels of CSF cortisol, cortisone, dehydroepiandrosterone (DHEA), 7α-OH-DHEA, 7β-OH-DHEA, 7-oxo-DHEA, 16α-OH-DHEA and aldosterone (all LC-MS/MS) were determined in our patients ( n = 30; NPH, 65–80 years) and controls (n = 10; 65–80 years). The model of orthogonal projections to latent structures (OPLS) was constructed to predict NPH. Cortisone, 7α-OH-DHEA, 7β-OH-DHEA, 7-oxo-DHEA, aldosterone, 7α-OH-DHEA /DHEA, 7-oxo-DHEA/7α-OH-DHEA, 7β-OH-DHEA/7-oxo-DHEA and 16α-OH-DHEA/DHEA in the CSF were identified as the key predictors and the model discriminated patients from controls with 100% sensitivity and 100% specificity. The suggested model would contribute to early and accurate NPH diagnosis, enabling promptly treatment of the disease. [ABSTRACT FROM AUTHOR]

Aldosterone or glucocorticoid stimulation of the mineralocorticoid receptor (MR) is involved in numerous physiological responses, including ions and water homeostasis, blood pressure control and metabolism. The understanding of MR signaling regulation in the patho/physiological context took a new direction the last few years with a focus on the post-translational modifications of MR. Depending on its environment, cellular expression, activity or its binding partners, the MR is submitted to several post-translational modifications such as phosphorylation, ubiquitylation, sumoylation and acetylation that regulate its localization, activity and/or stability. A complex interplay between all these modifications allows a fine tuning of MR signaling depending on the physiological context. This review reports recent knowledge about post-translational modifications of MR and describes the enzymes and the molecular mechanisms involved. [ABSTRACT FROM AUTHOR]

Apparent mineralocorticoid excess is a syndrome reflecting the absent or impaired activity of the enzyme 11β-hydroxysteroid dehydrogenase Type 2. It may be mild when the mutant enzyme retains some activity, or severe when activity is absolutely or essentially absent. Diagnosis relies on a triad of hypertension, hypokalemia and suppressed plasma aldosterone levels, plus an abnormal urinary cortisol to cortisone ratio, either free steroid or metabolites. Treatment is symptomatic in the mild form – correction of hypertension and hypokalemia – but needs to be prompt, vigorous and sustained in the severe form, which usually presents in neonates/infancy. Elucidation of the pathogenesis of apparent mineralocorticoid excess is an example of ‘reverse translation’, in that it proved prismatic for the demonstration of the physiologic mechanisms underlying the selective activation of epithelial mineralocorticoid receptors by aldosterone. [ABSTRACT FROM AUTHOR]

Highlights: [•] Lamprey CR has both MR and GR activity. [•] Skate GR has a low transcriptional response to 1α-OH-corticosterone. [•] GR is descended from the MR. [•] Ser-169 in coelacanth MR corresponds to Ser-810 in hMR. [•] Coelacanth GR lacks the serine corresponding to Ser-810 in hMR. [Copyright &y& Elsevier]

Abstract: The mineralocorticoid receptor (MR) classically mediates aldosterone effects on salt homeostasis and blood pressure regulation in epithelial target tissues. In recent years, functional MRs have been identified in non classical targets of aldosterone actions, in particular in adipose tissue, where they mediate the effects of aldosterone and glucocorticoids in the control of adipogenesis, adipose expansion and its pro-inflammatory capacity. In this context, inappropriate MR activation has been demonstrated to be a causal factor in several pathologic conditions such as vascular inflammation, endothelial dysfunction, insulin resistance and obesity. The aim of this review is to summarize the latest developments in this rapidly developing field, and will focus on the role of MR and renin–angiotensin–aldosterone system (RAAS) as potential leading characters in the early steps of adipocyte dysfunction and obesity. Indeed modulation of MR activity in adipose tissue has promise as a novel therapeutic approach to treat obesity and its related metabolic complications. This article is part of a Special Issue entitled ‘CSR 2013’. [Copyright &y& Elsevier]

• Human mineralocorticoids, aldosterone and 11-deoxycorticosterone activate lungfish MR. • Human glucocorticoids, cortisol and corticosterone activate lungfish MR. • Progesterone, a human MR antagonist, activates lungfish MR. Aldosterone, the main physiological mineralocorticoid in humans and other terrestrial vertebrates, first appears in lungfish, which are lobe-finned fish that are forerunners of terrestrial vertebrates. Aldosterone activation of the MR regulates internal homeostasis of water, sodium and potassium, which was critical in the conquest of land by vertebrates. We studied transcriptional activation of the slender African lungfish MR by aldosterone, other corticosteroids and progesterone and find that aldosterone, 11-deoxycorticosterone, 11-deoxycortisol and progesterone have half-maximal responses (EC50 s) below 1 nM and are potential physiological mineralocorticoids. In contrast, EC50 s for corticosterone and cortisol were 23 nM and 66 nM, respectively. Unexpectedly, truncated lungfish MR, consisting of the DNA-binding, hinge and steroid-binding domains, had a stronger response to corticosteroids and progesterone than full-length lungfish MR, indicating that the N-terminal domain represses steroid activation of lungfish MR, unlike human MR in which the N-terminal domain contains an activation function. BLAST searches of GenBank did not retrieve a GR ortholog, leading us to test dexamethasone and triamcinolone for activation of lungfish MR. At 10 nM, both synthetic glucocorticoids are about 4-fold stronger than 10 nM aldosterone in activating full-length lungfish MR, leading us to propose that lungfish MR also functions as a GR. [ABSTRACT FROM AUTHOR]

• Glycyrrhetinic acid-like factors (GALFs) may contribute to essential hypertension and other diseases. • GALFs comprise various endogenous steroidal inhibitors of 11β-HSD dehydrogenase. • The simultaneous presence of several GALFs and substrates of 11β-HSDs should be considered. • The local microenvironment determines 11β-HSD activity and impacts blood pressure. • Plasma as well as tissue concentrations of various GALFs need to be determined in health and disease. 11β-Hydroxysteroid dehydrogenase (11β-HSD)-dependent conversion of cortisol to cortisone and corticosterone to 11-dehydrocorticosterone are essential in regulating transcriptional activities of mineralocorticoid receptors (MR) and glucocorticoid receptors (GR). Inhibition of 11β-HSD by glycyrrhetinic acid metabolites, bioactive components of licorice, causes sodium retention and potassium loss, with hypertension characterized by low renin and aldosterone. Essential hypertension is a major disease, mostly with unknown underlying mechanisms. Here, we discuss a putative mechanism for essential hypertension, the concept that endogenous steroidal compounds acting as glycyrrhetinic acid-like factors (GALFs) inhibit 11β-HSD dehydrogenase, and allow for glucocorticoid-induced MR and GR activation with resulting hypertension. Initially, several metabolites of adrenally produced glucocorticoids and mineralocorticoids were shown to be potent 11β-HSD inhibitors. Such GALFs include modifications in the A-ring and/or at positions 3, 7 and 21 of the steroid backbone. These metabolites may be formed in peripheral tissues or by gut microbiota. More recently, metabolites of 11β-hydroxy-Δ4androstene-3,17-dione and 7-oxygenated oxysterols have been identified as potent 11β-HSD inhibitors. In a living system, 11β-HSD isoforms are not exposed to a single substrate but to several substrates, cofactors, and various inhibitors simultaneously, all at different concentrations depending on physical state, tissue and cell type. We propose that this "cloud" of steroids and steroid-like substances in the microenvironment determines the 11β-HSD-dependent control of MR and GR activity. A dysregulated composition of this cloud of metabolites in the respective microenvironment needs to be taken into account when investigating disease mechanisms, for forms of low renin, low aldosterone hypertension. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between helix 3 and helix 5 in the human mineralocorticoid receptor [MR], progesterone receptor [PR] and glucocorticoid receptor [GR] influences their response to steroids. For the human PR, mutations at Gly-722 on helix 3 and Met-759 on helix 5 alter responses to progesterone. We analyzed the evolution of these two sites and the rest of a 59 residue segment containing helices 3, 4 and 5 in vertebrate PRs and found that a glycine corresponding to Gly-722 on helix 3 in human PR first appears in platypus, a monotreme. In lamprey, skates, fish, amphibians and birds, cysteine is found at this position in helix 3. This suggests that the cysteine to glycine replacement in helix 3 in the PR was important in the evolution of mammals. Interestingly, our analysis of the rest of the 59 residue segment finds 100% sequence conservation in almost all mammal PRs, substantial conservation in reptile and amphibian PRs and divergence of land vertebrate PR sequences from the fish PR sequences. The differences between fish and land vertebrate PRs may be important in the evolution of different biological progestins in fish and mammalian PR, as well as differences in susceptibility to environmental chemicals that disrupt PR-mediated physiology. [Copyright &y& Elsevier]

Recent reports describe the ability of factors to modulate the position of the dose–response curve of receptor–agonist complexes, and the amount of partial agonist activity of receptor–antagonist complexes, of androgen, glucocorticoid (GRs), and progesterone receptors (PRs). We now ask whether this modulation extends to the two remaining steroid receptors: mineralocorticoid (MRs) and estrogen receptors (ERs). These studies of MR were facilitated by our discovery that the antiglucocorticoid dexamethasone 21-mesylate (Dex-Mes) is a new antimineralocorticoid with significant amounts of partial agonist activity. Elevated levels of MR, the co-activators TIF2 and SRC-1, and the co-repressor SMRT do modulate the dose–response curve and partial agonist activity of MR complexes. Interestingly, the precise responses are indistinguishable from those seen with GRs in the same cells. Thus, the unequal transactivation of common genes by MRs versus GRs probably cannot be explained by differential responses to changing cellular concentrations of homologous receptor, co-activators, or co-repressors. We also find that the dose–response curve of ER–estradiol complexes is left-shifted to lower steroid concentrations by higher amounts of exogenous ER. Therefore, the modulation of either the dose–response curve of agonists or the partial agonist activity of antisteroid, and in many cases the modulation of both properties, is a common phenomenon for all of the classical steroid receptors. [Copyright &y& Elsevier]

• GR N-terminal domain activates elephant shark GR. • GR N-terminal domain activates elephant shark MR. • GR DNA-binding domain activates elephant shark GR. Orthologs of human glucocorticoid receptor (GR) and human mineralocorticoid receptor (MR) first appear in cartilaginous fishes. Subsequently, the MR and GR diverged to respond to different steroids: the MR to aldosterone and the GR to cortisol and corticosterone. We report that cortisol, corticosterone and aldosterone activate full-length elephant shark GR, and progesterone, which activates elephant shark MR, does not activate elephant shark GR. However, progesterone inhibits steroid binding to elephant shark GR, but not to human GR. Together, this indicates partial functional divergence of elephant shark GR from the MR. Deletion of the N-terminal domain (NTD) from elephant shark GR (truncated GR) reduced the response to corticosteroids, while truncated and full-length elephant shark MR had similar responses to corticosteroids. Swapping of NTDs of elephant shark GR and MR yielded an elephant shark MR chimera with full-length GR-like increased activation by corticosteroids and progesterone compared to full-length elephant shark MR. Elephant shark MR NTD fused to GR DBD + LBD had similar activation as full-length MR, indicating that the MR NTD lacked GR-like NTD activity. We propose that NTD activation of human GR evolved early in GR divergence from the MR. [ABSTRACT FROM AUTHOR]

• Renal pseudohypoaldosteronism was diagnosed in 15 members of an extended family spanning four generations. • The affected members had a deletion in the NR3C2 gene coding for the mineralocorticoid receptor. • Aldosterone levels remain elevated over four decades despite age-dependent decrease. • The diagnosis of the proband allowed early diagnosis with improved clinical outcome in other infants. Renal pseudohypoaldosteronism (PHA1) is a mild form of an aldosterone-resistance syndrome caused by mutations in the NR3C2 gene that codes for the mineralocorticoid receptor (MR). The disease is inherited as an autosomal dominant trait characterized by signs and symptoms of salt-losing in infancy. Disease manifestations could be severe in infancy but improve after the age of 1–3 years. Some affected members are asymptomatic and remain so life-long. In this study, we report the identification of a large deletion in the NR3C2 gene (c.1897+1_1898−1)_(c.*2955+?)del in renal PHA1 patients from an extended family spanning four generations. We prospectively evaluated the plasma renin activity and serum aldosterone profiles over four decades in symptomatic and asymptomatic affected family members. The benefits of early diagnosis on the clinical outcome were assessed as well. The long-term follow-up showed an age-dependent decrease in both plasma renin activity and serum aldosterone levels over the years. However, aldosterone levels remain high life-long. Thus, levels of aldosterone are a reliable marker to detect asymptomatic family members. The diagnosis of the proposita led to early diagnosis and therapy in other affected family members, significantly mitigating the clinical course. Despite the extremely elevated serum aldosterone levels during pregnancy, affected pregnant women did not experience any ill effects. However, this should be verified by observations in other adult patients. [ABSTRACT FROM AUTHOR]

• Aldosterone (Aldo) induces FSH-induced progesterone synthesis by rat granulosa cells (GCs). • Aldo increases progesterogenic enzyme expression by suppressing BMP-Smad signaling. • Aldo upregulates inhibitory Smad6, while BMP-6 suppresses MR expression on rat GCs. Aldosterone (Aldo) is involved in various cardiovascular diseases such as hypertension and heart failure. Aldo levels are known to be increased in patients with polycystic ovary syndrome, and expression of the mineralocorticoid receptor (MR) has also been detected in the ovary. However, the effect of Aldo on reproductive function has yet to be elucidated. Here, we examined the effects of Aldo on follicular steroidogenesis using primary culture of rat granulosa cells by focusing on the ovarian bone morphogenetic protein (BMP) system acting as a luteinizing inhibitor. We found that Aldo treatment increased FSH-induced progesterone production in a concentration-responsive manner. Consistent with the effects on steroidogenesis, Aldo increased mRNA levels of progesterogenic factor and enzymes including StAR and P450scc, whereas Aldo failed to change FSH-induced estradiol and cAMP synthesis or P450arom expression by granulosa cells. Progesterone production and StAR expression induced by FSH and Aldo were reversed by co-treatment with spironolactone, suggesting the involvement of geonomic MR action. Aldo treatment attenuated Smad1/5/9 phosphorylation and Id1 transcription induced by BMP-6. Furthermore, Aldo enhanced the expression of inhibitory Smad6 in the presence of BMP-6. In addition, BMP-6 downregulated MR expression, while Aldo modulated the mRNA levels of endogenous BMP-6 and BMP type-II receptors, indicating the existence of a feedback loop between the BMP system and MR in granulosa cells. Collectively, the results indicated that Aldo predominantly enhances FSH-induced progesterone production by inhibiting BMP-Smad signaling, suggesting a novel role of Aldo in ovarian steroidogenesis and a functional link between MR and BMP pathways in granulosa cells. [ABSTRACT FROM AUTHOR]

• Posaconazole and itraconazole can cause hypertension and hypokalemia. • Posaconazole preferably inhibits CYP11B1 and itraconazole preferably 11β-HSD2. • Voriconazole, fluconazole and isavuconazole neither inhibit CYP11B1 nor 11β-HSD2. • Molecular docking calculations provide an explanation for the observed inhibitory effects. • None of the analyzed azole antifungals acts through CYP17A1 or mineralocorticoid receptors. Recent reports described cases of severe hypertension and hypokalemia accompanied by low renin and aldosterone levels during antifungal therapy with posaconazole and itraconazole. These conditions represent characteristics of secondary endocrine hypertension caused by mineralocorticoid excess. Different mechanisms can cause mineralocorticoid excess, including inhibition of the adrenal steroidogenic enzymes CYP17A1 and CYP11B1, inhibition of the peripheral cortisol oxidizing enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) or direct activation of the mineralocorticoid receptor (MR). Compared to previous experiments revealing a threefold more potent inhibition of 11β-HSD2 by itraconazole than with posaconazole, the current study found sevenfold stronger CYP11B1 inhibition by posaconazole over itraconazole. Both compounds most potently inhibited CYP11B2. The major pharmacologically active itraconazole metabolite hydroxyitraconazole (OHI) resembled the effects of itraconazole but was considerably less active. Molecular modeling calculations assessed the binding of posaconazole, itraconazole and OHI to 11β-HSD2 and the relevant CYP enzymes, and predicted important interactions not formed by the other systemically used azole antifungals, thus providing an initial explanation for the observed inhibitory activities. Together with available clinical observations, the presented data suggest that itraconazole primarily causes pseudohyperaldosteronism through cortisol-induced MR activation due to 11β-HSD2 inhibition, and posaconazole by CYP11B1 inhibition and accumulation of the mineralocorticoids 11-deoxycorticosterone and 11-deoxycortisol because of hypothalamus-pituitary-adrenal axis (HPA) feedback activation. Therapeutic drug monitoring and introduction of upper plasma target levels may help preventing the occurrence of drug-induced hypertension and hypokalemia. Furthermore, the systemically used azole antifungals voriconazole, isavuconazole and fluconazole did not affect any of the mineralocorticoid excess targets, offering alternative therapeutic options. [ABSTRACT FROM AUTHOR]

• Biotransformation of spironolactone by human adrenal was directly demonstrated. • Adrenal drug metabolism shown. • Novel metabolites are formed. • 11- and 18-hydroxylated metabolites of canrenone were found in adrenal venous blood. The metabolism of drugs in mammals is attributed mainly to the liver and its cytochromes P450 localized in the endoplasmic reticulum. Here, we demonstrate for the first time in humans that there is no strict subdivision between P450 s involved in exogenous and endogenous metabolism. We determined the widely used mineralocorticoid receptor antagonist spironolactone, its active metabolite canrenone and their metabolites in the adrenal venous blood of treated patients with gas chromatography-mass spectrometry. 11- and 18-hydroxylated metabolites of canrenone were found in the efferent right and left adrenal veins, indicating that they were produced by the adrenal mitochondrial cytochromes P450 CYP11B1 and CYP11B2. Thus, the adrenal has to be considered as a new organ for drug metabolism. In future, application of drugs may need further investigations concerning side effects due to interactions with adrenal enzymes. [ABSTRACT FROM AUTHOR]

• Glucocorticoid binds to GR to inhibit testosterone production in Leydig cells. • Glucocorticoid binds to MR to stimulate testosterone production in Leydig cells. • 11β-Hydroxysteroid dehydrogenases control glucocorticoid levels in Leydig cells. • 11β-Hydroxysteroid dehydrogenase 1 direction is coupled by several steroidogenic enzymes. Glucocorticoid is secreted by adrenal cortex, which binds to intracellular glucocorticoid and mineralocorticoid receptors to regulate steroidogenesis-related gene expression and testosterone production in Leydig cells. Glucocorticoid receptor activity shows inhibitory action on Leydig cell steroidogenesis, while mineralocorticoid receptor activity shows the stimulatory action. Leydig cells contain two important glucocorticoid-metabolizing enzymes, 11β-hydroxysteroid dehydrogenase type 1 and type 2, regulating the intracellular levels of glucocorticoids by a pre-receptor mechanism. 11β-Hydroxysteroid dehydrogenase type 1 is a bidirectional enzyme, and its direction is regulated by intracellular NADP+/NADPH redox potential. Leydig cells contain many steroidogenic enzymes, possibly regulating NADP+/NADPH redox potential by coupling with 11β-hydroxysteroid dehydrogenase type 1. Here, we review the 11β-hydroxysteroid dehydrogenase regulation and possible consequences in Leydig cell biology and pathology. [ABSTRACT FROM AUTHOR]