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Responses to hormones that act through nuclear receptors are controlled by modulating hormone concentrations not only in the circulation but also within target tissues. The role of enzymes that amplify or reduce local hormone concentrations has become well-established for glucocorticoid and other lipophilic hormones; moreover, transmembrane transporters have proven critical in determining tissue responses to thyroid hormones. However, there has been less consideration of the role of transmembrane transport for steroid hormones. ATP-binding cassette (ABC) proteins were first shown to influence the accumulation of glucocorticoids in cells almost three decades ago, butobservations over the past ten years suggest that differential transport propensities of both exogenous and endogenous glucocorticoids by ABCB1 and ABCC1 transporters provides a mechanism whereby different tissues are preferentially sensitive to different steroids. This Review summarisesthis evidence and the new insights provided for the physiology and pharmacology of glucocorticoid action, including new approaches to glucocorticoid replacement.

Using a model of UV-killedE. colidriven dermal inflammation in healthy human volunteers we originally reported that following inflammatory resolution there was the infiltration of macrophages, which, through prostanoids including prostaglandin (PG)E2, imprints long-term tissue immunity. In addition to the prostanoids, we also presented data on levels ofSpecialisedPro-Resolution LipidMediators (SPMs) throughout inflammatory onset, resolution and post-resolution phases of this model. However, our collaborators who carried out the lipidomic analysis received a complaint concerning how they generally present SPM data in their publications, namely their use of graphical illustrations to depict data. Importantly, such lipidomic illustrations were used in our human UV-killedE. colistudy. Therefore, in the interest of transparency and to replace these illustrations with more meaningful images, the original data from our human UV-killedE. colimodel were re-analysed by two independent experts. It transpires that the integrated areas of the chromatographic peaks of the SPM lipid mediators were below the amounts that could be reliably either detected and/or quantified using community standards for quantitation. Here we show the outcome of this reanalysis. Importantly, with prostanoids including PGE2being robustly detected, this re-analysis does not alter the original report that post-resolution PGs imprint tissue immunity.

Genome wide association meta-analyses (GWAMA) by the CORtisol NETwork (CORNET) consortium identified genetic variants spanning theSERPINA6/ SERPINA1locus on chromosome 14 associated with morning plasma cortisol, cardiovascular disease (CVD), andSERPINA6mRNA expression encoding corticosteroid binding globulin (CBG) in liver. These and other findings indicate that higher plasma cortisol levels are causally associated with cardiovascular disease, however, the mechanisms by which variations in CBG lead to CVD are undetermined. Using genomic and transcriptomic data from The Stockholm Tartu Atherosclerosis Reverse Networks Engineering Task (STARNET) study, we identified plasma cortisol linked Single Nucleotide Polymorphisms (SNPs) that are trans-associated with genes from 7 different vascular and metabolic tissues, finding the highest representation of transgenes in liver, subcutaneous adipose and visceral abdominal adipose tissue (FDR = 15%). We identified a sub-set of cortisol-associated trans-genes that are putatively regulated by the Glucocorticoid Receptor (GR), the primary transcription factor activated by cortisol. Using causal inference, we identified GR-regulated trans-genes that are responsible for the regulation of tissue specific gene networks. Cis-expression Quantitative Trait Loci (eQTLs) were used as genetic instruments for identification of pairwise causal relationships from which gene networks could be reconstructed. Gene networks were identified in liver, subcutaneous fat and visceral abdominal fat, including a high confidence gene network specific to subcutaneous adipose (FDR = 10%) under the regulation of the interferon regulatory transcription factor,IRF2. These data identify a plausible pathway through which variation in liver CBG production perturbs cortisol-regulated gene networks in peripheral tissues and thereby promote CVD.

Background and purposeKcnq-encoded KV7 channels (termed KV7.1-5) regulate vascular smooth muscle cell (VSMC) contractility at rest and as downstream targets of receptor mediated responses. However, the current literature focuses predominantly on males. Considering the known impact of sex, the oestrus cycle and sex-hormones on vascular reactivity, the aim of this investigation was to characterise the molecular and functional properties of KV7 within renal and mesenteric arteries from female Wistar rats separated into Di-oestrus and Met-oestrus (F-D/M) and Pro-oestrus and Oestrus (F-P/E).Experimental approachRT-qPCR, immunocytochemistry, proximity-ligation assay and wire myography were performed in renal and mesenteric arteries. Circulating sex-hormone concentrations was determined by liquid chromatography tandem mass-spectrometry. Whole-cell electrophysiology undertaken on cells expressing KV7.4 in association with G-protein coupled Oestrogen receptor 1 (GPER1).Key resultsThe KV7.2-5 activators S-1/ML213 and the pan-KV7 inhibitor Linopirdine were more effective in arteries from F-D/M compared to F-P/E animals. In VSMCs isolated from F-P/E rats, the membrane abundance of KV7.4 but not KV7.1, KV7.5 and Kcne4 was reduced compared to F-D/M cells. Plasma oestradiol was significantly higher in F-P/E compared to F-D/M and progesterone showed the converse pattern. Oestradiol/GPER1 agonist G-1 diminished KV7.4 currents in heterologous expression system and reduced KV7.4 membrane abundance, ML213 relaxations, and interaction between KV7.4 and the molecular chaperone protein, heat shock protein 90 (HSP90), in arteries from F-D/M but not F-P/E.Conclusions and implicationsGPER1 signalling decreases KV7.4 membrane abundance in conjunction with diminished interaction with HSP90, giving rise to a ‘pro-contractile state.’

Kcnq-encoded KRT-qPCR, immunocytochemistry, proximity ligation assay and wire myography were performed in renal and mesenteric arteries. Circulating sex hormone concentrations were determined by liquid chromatography-tandem mass spectrometry. Whole-cell electrophysiology was undertaken on cells expressing KThe KGPER1 signalling decreased K

5α-Tetrahydrocorticosterone (5αTHB) is an effective topical anti-inflammatory agent in mouse, with less propensity to cause skin thinning and impede new blood vessel growth compared with corticosterone. Its anti-inflammatory effects were not prevented by RU38486, a glucocorticoid receptor antagonist, suggesting alternative mechanisms. The hypothesis that 5αTHB directly inhibits angiogenesis to a lesser extent than hydrocortisone was tested, focussing on glucocorticoid receptor mediated actions. New vessel growth from aortae from C57BL/6 male mice was monitored in culture, in the presence of 5αTHB, hydrocortisone (mixed glucocorticoid/mineralocorticoid receptor agonist) or the selective glucocorticoid receptor agonist dexamethasone. Transcript profiles were studied, as was the role of the glucocorticoid receptor, using the antagonist, RU38486. Ex vivo, 5αTHB suppressed vessel growth from aortic rings, but was less potent than hydrocortisone (EC50 2512 nM 5αTHB, versus 762 nM hydrocortisone). In contrast to conventional glucocorticoids, 5αTHB did not alter expression of genes related to extracellular matrix integrity or inflammatory signalling, but caused a small increase in Per1 transcript, and decreased transcript abundance of Pecam1 genes. RU38486 did not antagonise the residual effects of 5αTHB to suppress vessel growth or regulate gene expression, but modified effects of dexamethasone. 5αTHB did not alter expression of glucocorticoid-regulated genes Fkbp51 and Hsd11b1, unlike hydrocortisone and dexamethasone. In conclusion, compared with hydrocortisone, 5αTHB exhibits limited suppression of angiogenesis, at least directly in blood vessels and probably independent of the glucocorticoid receptor. Discriminating the mechanisms employed by 5αTHB may provide the basis for the development of novel safer anti-inflammatory drugs for topical use.

Context Body fat distribution is a risk factor for obesity-associated comorbidities, and adipose tissue dysfunction plays a role in this association. In humans, there is a sex difference in body fat distribution, and steroid hormones are known to regulate several cellular processes within adipose tissue. Objective Our aim was to investigate if intra-adipose steroid concentration and expression or activity of steroidogenic enzymes were associated with features of adipose tissue dysfunction in individuals with severe obesity. Methods Samples from 40 bariatric candidates (31 women, 9 men) were included in the study. Visceral (VAT) and subcutaneous adipose tissue (SAT) were collected during surgery. Adipose tissue morphology was measured by a combination of histological staining and semi-automated quantification. Following extraction, intra-adipose and plasma steroid concentrations were determined by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Aromatase activity was estimated using product over substrate ratio, while AKR1C2 activity was measured directly by fluorogenic probe. Gene expression was measured by quantitative PCR. Results VAT aromatase activity was positively associated with VAT adipocyte hypertrophy (P valueadj Conclusion In women, increased androgen catabolism or aromatization is associated with visceral adiposity and adipose tissue dysfunction.

Background and Aims: Portopulmonary hypertension (POPH) was previously associated with a single-nucleotide polymorphism (SNP) rs7175922 in aromatase (cytochrome P450 family 19 subfamily A member 1 [CYP19A1]). We sought to determine whether genetic variants and metabolites in the estrogen signaling pathway are associated with POPH. Approach and Results: We performed a multicenter case-control study. POPH patients had mean pulmonary artery pressure >25 mm Hg, pulmonary vascular resistance >240 dyn-sec/cm −5, and pulmonary artery wedge pressure ≤15 mm Hg without another cause of pulmonary hypertension. Controls had advanced liver disease, right ventricular (RV) systolic pressure

Objective Sex differences in disease susceptibility might be explained by sexual dimorphism in hypothalamic-pituitary-adrenal axis activity, which has been postulated to emerge during puberty. However, studies conducted thus far lacked an assessment of Tanner pubertal stage. This study aimed to assess the contribution of pubertal development to sexual dimorphism in cortisol production and metabolism. Methods Participants (n = 218) were enrolled from a population-based Netherlands Twin Register. At the ages of 9, 12 and 17 years, Tanner pubertal stage was assessed and early morning urine samples were collected. Cortisol metabolites were measured with GC-MS/MS and ratios were calculated, representing cortisol metabolism enzyme activities, such as A-ring reductases, 11β-HSDs and CYP3A4. Cortisol production and metabolism parameters were compared between sexes for pre-pubertal (Tanner stage 1), early pubertal (Tanner stage 2–3) and late-pubertal (Tanner stage 4–5) stages. Results Cortisol metabolite excretion rate decreased with pubertal maturation in both sexes, but did not significantly differ between sexes at any pubertal stage, although in girls a considerable decrease was observed between early and late-pubertal stage (P < 0.001). A-ring reductase activity was similar between sexes at pre- and early pubertal stages and was lower in girls than in boys at late-pubertal stage. Activities of 11β-HSDs were similar between sexes at pre-pubertal stage and favored cortisone in girls at early and late-pubertal stages. Cytochrome P450 3A4 activity did not differ between sexes. Conclusions Prepubertally, sexes were similar in cortisol parameters. During puberty, as compared to boys, in girls the activities of A-ring reductases declined and the balance between 11β-HSDs progressively favored cortisone. In addition, girls showed a considerable decrease in cortisol metabolite excretion rate between early and late-pubertal stages. Our findings suggest that the sexual dimorphism in cortisol may either be explained by rising concentrations of sex steroids or by puberty-induced changes in body composition.

Context Across pregnancy, maternal serum cortisol levels increase up to 3-fold. It is not known whether maternal peripheral cortisol metabolism and clearance change across pregnancy or influence fetal cortisol exposure and development. Objectives The primary study objective was to compare maternal urinary glucocorticoid metabolites, as markers of cortisol metabolism and clearance, between the second and third trimester of pregnancy. Secondary objectives were to test associations of total maternal urinary glucocorticoid excretion, with maternal serum cortisol levels and offspring birth weight z score. Design, Participants, and Setting A total of 151 women with singleton pregnancies, recruited from prenatal clinic at the Pittsburgh site of the Measurement of Maternal Stress (MOMS) study, had 24-hour urine collections during both the second and third trimesters. Results Between the second and third trimester, total urinary glucocorticoid excretion increased (ratio of geometric means [RGM] 1.37, 95% CI 1.22-1.52, P < .001), and there was an increase in calculated 5β-reductase compared to 5α-reductase activity (RGM 3.41, 95% CI 3.04-3.83, P < .001). During the third trimester total urinary glucocorticoid excretion and serum cortisol were negatively correlated (r = –0.179, P = .029). Mean total urinary glucocorticoid excretion across both trimesters and offspring birth weight z score were positively associated (β = 0.314, P = .001). Conclusions The estimated activity of maternal enzymes responsible for cortisol metabolism change between the second and third trimester of pregnancy. Additionally, maternal peripheral metabolism and clearance of cortisol may serve as a novel mechanism affecting fetal cortisol exposure and growth.

Context Altered tissue-specific glucocorticoid metabolism has been described in uncomplicated obesity and type 2 diabetes. We hypothesized that weight loss induced by diet and exercise, which has previously been shown to reverse abnormal cortisol metabolism in uncomplicated obesity, also normalizes cortisol metabolism in patients with type 2 diabetes. Objective Test the effects of a diet intervention with added exercise on glucocorticoid metabolism. Design Two groups followed a Paleolithic diet (PD) for 12 weeks with added 180 min of structured aerobic and resistance exercise per week in one randomized group (PDEX). Setting Umeå University Hospital. Participants Men and women with type 2 diabetes treated with lifestyle modification ± metformin were included. Twenty-eight participants (PD, n = 15; PDEX, n = 13) completed measurements of glucocorticoid metabolism. Main outcome measures Changes in glucocorticoid metabolite levels in 24-h urine samples, expression of HSD11B1 mRNA in s.c. adipose tissue and conversion of orally administered cortisone to cortisol measured in plasma. Body composition and insulin sensitivity were measured using a hyperinsulinemic-euglycemic clamp, and liver fat was measured by magnetic resonance spectroscopy. Results Both groups lost weight and improved insulin sensitivity. Conversion of orally taken cortisone to plasma cortisol and the ratio of 5α-THF + 5β-THF/THE in urine increased in both groups. Conclusions These interventions caused weight loss and improved insulin sensitivity with concomitant increases in the conversion of cortisone to cortisol, which is an estimate of hepatic HSD11B1 activity. This suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.

Life-course experiences have been postulated to program hypothalamus–pituitary–adrenal (HPA) axis activity, suggesting that HPA axis activity is, at least partially, stable over time. Yet, there is paucity of data on the long-term stability of cortisol production and metabolism. We performed a prospective follow-up study in twins recruited from a nationwide register to estimate the stability of cortisol production and metabolism over time, and the contribution of genetic and environmental factors to this stability. In total, 218 healthy mono- and dizygotic twins were included. At the ages of 9, 12 and 17 years, morning urine samples were collected for assessment (by gas chromatography-tandem mass spectrometry) of cortisol metabolites, enabling the calculation of cortisol metabolite excretion rate and cortisol metabolism activity. Our results showed a low stability for both cortisol metabolite excretion rate (with correlations

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) amplifies tissue glucocorticoid levels and is a pharmaceutical target in diabetes and cognitive decline. Clinical translation of inhibitors is hampered by lack of in vivo pharmacodynamic biomarkers. Our goal was to monitor substrates and products of 11β-HSD1 non-invasively in liver via 19Fluorine magnetic resonance spectroscopy (19F-MRS). Interconversion of mono/poly-fluorinated substrate/product pairs was studied in Wistar rats (male, n = 6) and healthy men (n = 3) using 7T and 3T MRI scanners, respectively. Here we show that the in vitro limit of detection, as absolute fluorine content, was 0.625 μmole in blood. Mono-fluorinated steroids, dexamethasone and 11-dehydrodexamethasone, were detected in phantoms but not in vivo in human liver following oral dosing. A non-steroidal polyfluorinated tracer, 2-(phenylsulfonyl)-1-(4-(trifluoromethyl)phenyl)ethanone and its metabolic product were detected in vivo in rat liver after oral administration of the keto-substrate, reading out reductase activity. Administration of a selective 11β-HSD1 inhibitor in vivo in rats altered total liver 19F-MRS signal. We conclude that there is insufficient sensitivity to measure mono-fluorinated tracers in vivo in man with current dosage regimens and clinical scanners. However, since reductase activity was observed in rats using poly-fluorinated tracers, this concept could be pursued for translation to man with further development.

Hormones regulate metabolic homeostasis through interlinked dynamic networks of proteins and small molecular weight metabolites and state-of-the-art chemical technologies have been developed to decipher these complex pathways. Stable-isotope tracers have largely replaced radiotracers to measure flux in humans, building on advances in nuclear magnetic resonance spectroscopy and mass spectrometry. These technologies are now being applied to localise molecules within tissues. Radiotracers are still highly valuable both preclinically and in 3D imaging by positron emission tomography. The coming of age of vibrational spectroscopy in conjunction with stable-isotope tracing offers detailed cellular insights to map complex biological processes. Together with computational modelling, these approaches are poised to coalesce into multi-modal platforms to provide hitherto inaccessible dynamic and spatial insights into endocrine signalling.

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) amplifies tissue glucocorticoid levels and is a pharmaceutical target in diabetes and cognitive decline. Clinical translation of inhibitors is hampered by lack of in vivo pharmacodynamic biomarkers. Our goal was to monitor substrates and products of 11β-HSD1 non-invasively in liver via

Context Inter-individual differences in cortisol production and metabolism emerge with age and may be explained by genetic factors. Objective To estimate the relative contributions of genetic and environmental factors to inter-individual differences in cortisol production and metabolism throughout adolescence. Design Prospective follow-up study of twins. Setting Nationwide register. Participants 218 mono- and dizygotic twins (N = 109 pairs) born between 1995 amd 1996, recruited from the Netherlands Twin Register. Cortisol metabolites were determined in 213, 169, and 160 urine samples at the ages of 9, 12, and 17, respectively. Main outcome measures The total contribution of genetic factors (broad-sense heritability) and shared and unshared environmental influences to inter-individual differences in cortisol production and activities of 5α-reductase, 5β-reductase, and 11β-hydroxysteroid dehydrogenases and cytochrome P450 3A4. Results For cortisol production rate at the ages of 9, 12, and 17, broad-sense heritability was estimated as 42%, 30%, and 0%, respectively, and the remainder of the variance was explained by unshared environmental factors. For cortisol metabolism indices, the following heritability was observed: for the A-ring reductases (5α-and 5β-reductases), broad-sense heritability increased with age (to >50%), while for the other indices (renal 11β-HSD2, global 11β-HSD, and CYP3A4), the contribution of genetic factors was highest (68%, 18%, and 67%, respectively) at age 12. Conclusions The contribution of genetic factors to inter-individual differences in cortisol production decreased between 12 and 17y, indicative of a predominant role of individual circumstances. For cortisol metabolism, distinct patterns of genetic and environmental influences were observed, with heritability that either increased with age or peaked at age 12y.

Rationale: Sex hormones play a role in pulmonary arterial hypertension (PAH), but the menstrual cycle has never been studied. Objectives: We conducted a prospective observational study of eight women with stable PAH and 20 healthy controls over one cycle. Methods: Participants completed four study visits 1 week apart starting on the first day of menstruation. Relationships between sex hormones, hormone metabolites, and extracellular vesicle microRNA (miRNA) expression and clinical markers were compared with generalized linear mixed modeling. Results: Women with PAH had higher but less variable estradiol (E2) levels (P

Highlights • Quantitative analysis of low abundance androgens in human plasma. • Quantitation of androgens over physiological range in men and post-menopausal women. • Use of hydrazine derivatives improves analytical sensitivity., Liquid Chromatography tandem mass spectrometry (LC-MS/MS) is the gold-standard approach for androgen analysis in biological fluids, superseding immunoassays in selectivity, particularly at low concentrations. While LC-MS/MS is established for analysis of testosterone and androstenedione, 5α-dihydrotestosterone (DHT) presents greater analytical challenges. DHT circulates at low nanomolar concentrations in men and lower in women, ionizing inefficiently and suffering from isobaric interference from other androgens. Even using current LC-MS/MS technology, large plasma volumes (>0.5 mL) are required for detection, undesirable clinically and unsuitable for animals. This study investigated derivatization approaches using hydrazine-based reagents to enhance ionization efficiency and sensitivity of analysis of DHT by LC-MS/MS. Derivatization of DHT using 2-hydrazino-1-methylpyridine (HMP) and 2-hydrazino-4-(trifluoromethyl)-pyrimidine (HTP) were compared. A method was validated using an UHPLC interfaced by electrospray with a triple quadruple mass spectrometer , analyzing human plasma (male and post-menopausal women) following solid-phase extraction. HMP derivatives were selected for validation affording greater sensitivity than those formed with HTP. HMP derivatives were detected by selected reaction monitoring (DHT-HMP m/z 396→108; testosterone-HMP m/z 394→108; androstenedione-HMP m/z 392→108). Chromatographic separation of androgen derivatives was optimized, carefully separating isobaric interferents and acceptable outputs for precision and trueness achieved following injection of 0.4 pg on column (approximately 34 pmol/L). HMP derivatives of all androgens tested could be detected in low plasma volumes: male (100 µL) and post-menopausal female (200 µL), and derivatives were stable over 30 days at -20°C. In conclusion, HMP derivatization, in conjunction with LC-MS/MS, is suitable for quantitative analysis of DHT, testosterone and androstenedione in low plasma volumes, offering advantages in sensitivity over current methodologies.

Steroid analysis is important in the clinical assessment of endocrine function in health and disease. Although tandem mass spectrometry methods coupled with chromatographic separation are considered the gold standard analytical technique in this setting, enabling profiling of multiple steroids in a single sample, sample processing can be labour-intensive. Here we present a simple, efficient automated 96-well Supported Liquid Extraction method with dichloromethane/isopropanol as organic solvent, carried out on a Extrahera automated sample handler (Biotage), which completes sample preparation of 80 plasma samples (200µL) in 90 minutes. Compounds were separated on a Kinetex C18 column (150x3mm;2.6um) using a mobile phase of methanol and water (0.1% formic acid). The run time was 16 minutes on a Nexera uHPLC system (Shimadzu) with a QTrap 6500+ linear ion trap mass spectrometer (AB Sciex). Precisions ranged 8.1 to 18.1% RSD, bias -10.1-5.8%, and extraction recoveries 73.5-111.9%. LOQs ranged between 0.025–0.500 ng/mL.

Childhood obesity is associated with alterations in hypothalamus&ndash, pituitary&ndash, adrenal (HPA) axis activity. However, it is unknown whether these alterations are a cause or a consequence of obesity. This study aimed to explore the temporal relationship between cortisol production and metabolism, and body mass index (BMI). This prospective follow-up study included 218 children (of whom 50% were male), born between 1995 and 1996, who were assessed at the ages of 9, 12 and 17 years. Morning urine samples were collected for assessment of cortisol metabolites by gas chromatography-tandem mass spectrometry, enabling the calculation of cortisol metabolite excretion rate and cortisol metabolic pathways. A cross-lagged regression model was used to determine whether BMI at various ages during childhood predicted later cortisol production and metabolism parameters, or vice versa. The cross-lagged regression coefficients showed that BMI positively predicted cortisol metabolite excretion (p = 0.03), and not vice versa (p = 0.33). In addition, BMI predicted the later balance of 11&beta, hydroxysteroid dehydrogenase (HSD) activities (p = 0.07), and not vice versa (p = 0.55). Finally, cytochrome P450 3A4 activity positively predicted later BMI (p = 0.01). Our study suggests that changes in BMI across the normal range predict alterations in HPA axis activity. Therefore, the alterations in HPA axis activity as observed in earlier studies among children with obesity may be a consequence rather than a cause of increased BMI.

Background Corticosteroid Binding Globulin (CBG) binds >85% of plasma cortisol and controls the circulating free cortisol pool. Proteolytic cleavage by neutrophil elastase is proposed to reduce CBG binding affinity and increase free cortisol availability to inflamed tissues. The CORtisol NETwork (CORNET) consortium found that genetic variation at a locus spanning SERPINA1 (encoding alpha-1 antitrypsin, A1AT, the endogenous inhibitor of neutrophil elastase) and SERPINA6 (CBG) contributes to morning total plasma cortisol variation. We hypothesised that A1AT deficiency increases CBG cleavage and hence free plasma cortisol, resulting in increased tissue cortisol delivery in adipose and in HPA axis negative feedback. We tested this in recall-by-genotype studies of people who are heterozygous for inactivating mutations in SERPINA1. Methods 16 healthy carriers of one of the two most common A1AT-deficiency single nucleotide polymorphisms (rs17580 & rs28929474) and 16 age-, gender- and BMI-matched controls were recruited from the Generation Scotland Biobank. Participants underwent combined receptor antagonist stimulation of the HPA axis (‘CRASH’) testing using RU486 400mg and spironolactone 200mg, or placebo in a double blind randomised crossover design. Plasma free cortisol was measured by isotopic dilution and ultrafiltration, total cortisol by LC-MS/MS, total CBG by ELISA, CBG binding capacity by radioligand displacement assay, and ACTH by immunoassay. Serum A1AT was measured by ELISA. Tissue cortisol (LC-MS/MS) and expression of glucocorticoid dependent transcripts (qPCR) were measured in subcutaneous adipose samples collected by needle biopsy. Results Serum A1AT was confirmed lower in those with heterozygous mutations vs wild type controls (411.3 +/- 27.44 vs 565.1 +/- 23.38 mg/dL, p=0.0002). No measurable differences in total CBG or CBG binding capacity were observed. However, plasma free cortisol fraction was higher in those carrying A1AT mutations (16.13 +/- 0.2 vs 13.88 +/- 0.04 %, p Conclusion Alpha-1 antitrypsin mutation heterozygosity, common in the general population, is associated with higher free cortisol fraction, consistent with enhanced cleavage of CBG. This is associated with evidence of enhanced delivery of glucocorticoid to adipose tissues but reduced HPA negative feedback, suggesting tissue-specific control of cortisol delivery by CBG.