Effect of Vasopressin on the Hypothalamic-Pituitary-Adrenal Axis in ADPKD Patients during V2 Receptor Antagonism.

BACKGROUND: Patients with autosomal dominant polycystic kidney disease (ADPKD) are treated with a vasopressin V2 receptor antagonist (V2RA) to slow disease progression. This drug increases vasopressin considerably in these patients with already elevated baseline levels. Vasopressin is known to stimulate the hypothalamic-pituitary-adrenal (HPA) axis through V1 and V3 receptor activation. It is unknown whether this increase in vasopressin during V2RA treatment affects glucocorticoid production. METHODS: Twenty-seven ADPKD patients were studied on and off treatment with a V2RA and compared to age- and sex-matched healthy controls and IgA nephropathy patients, the latter also matched for kidney function. Vasopressin was measured by its surrogate copeptin. Twenty-four-hour urinary excretions of cortisol, cortisone, tetrahydrocortisone, tetrahydrocortisol, allotetrahydrocortisol, and the total glucocorticoid pool were measured. RESULTS: At baseline, ADPKD patients demonstrated a higher copeptin concentration in comparison with healthy controls, while urinary excretion of cortisol and cortisone was lower (medians of 0.23 vs. 0.34 µmol/24 h, p = 0.007, and 0.29 vs. 0.53 µmol/24 h, p < 0.001, respectively). There were no differences in cortisol and cortisone excretion compared to IgA nephropathy patients. Cortisol, cortisone, and total glucocorticoid excretions correlated with kidney function (R = 0.37, 0.58, and 0.19, respectively; all p < 0.05). Despite that V2RA treatment resulted in a 3-fold increase in copeptin, only cortisone excretion increased (median of 0.44 vs. baseline 0.29 µmol/24 h, p < 0.001), whereas no changes in cortisol or total glucocorticoid excretion were observed. CONCLUSIONS: Increased concentration of vasopressin in ADPKD patients at baseline and during V2RA treatment does not result in activation of the HPA axis. The impaired glucocorticoid production in these patients is related to their degree of kidney function impairment.

Long-Term Stability of Cortisol Production and Metabolism Throughout Adolescence: Longitudinal Twin Study.

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 <.20) and cortisol metabolism activity indices (with correlations of .25 to .46 between 9 and 12 years, -.02 to .15 between 12 and 17 years and .09 to .28 between 9 and 17 years). Because of the low stability over time, genetic and environmental contributions to this stability were difficult to assess, although it seemed to be mostly determined by genetic factors. The low stability in both cortisol production and metabolism between ages 9 and 17 years reflects the dynamic nature of the HPA axis.

Effects of truck transportation and slaughtering on the occurrence of prednisolone and its metabolites in cow urine, liver, and adrenal glands.

BACKGROUND: The recognition of illegal administration of synthetic corticosteroids in animal husbandry has been recently challenged by the case of prednisolone, whose occasional presence in the urine of bovines under strong stressful conditions was attributed to endogenous biosynthesis, not to exogenous administration. The study of the natural stress sources possibly inducing endogenous prednisolone production represents a stimulating investigation subject. The biochemical effects of transportation and slaughtering were verified in untreated cows by studying the possible occurrence of prednisolone and its metabolites in urine, liver and adrenal glands, and the cortisol/cortisone quantification. RESULTS: Cortisol, cortisone, prednisolone and its metabolites were measured in urine, collected at farm under natural micturition and then at the slaughterhouse. The study was performed on 15 untreated cows reared in different farms at the end of their productive cycle. 2-3 days after the first urine collection, the animals were transported by trucks to the abattoir, slaughtered, and subjected to a second urine sampling from the bladder. Specimens of liver and adrenal gland were also collected and analysed by means of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) validated method. The stressful conditions of transportation and slaughtering proved to increase considerably the urinary levels of cortisol and cortisone as compared to those collected at farm. Prednisolone was detected in the urine collected at the slaughterhouse of two cows only, at a concentration level (≈0.6 µg L- 1) largely below the official cut off (5.0 µg L- 1) established to avoid false non-compliances. These two animals exhibited the highest urinary cortisol levels of the series. Prednisolone and prednisone were also detected in the adrenal glands of a different cow. Prednisolone metabolites were not detected in any urine, liver, and adrenal gland sample. CONCLUSION: Within the constraints of the condition adopted, this study confirms the sporadic presence of prednisolone traces (2 samples out of 15) and the consistently increased concentration of cortisone and cortisol in the urines collected from cows subjected to truck transportation and subsequent slaughtering. No prednisolone metabolites were detected in any liver and adrenal gland samples, nor in urine specimens, unlike what was previously reported for cows artificially stressed by pharmacological treatment.

DIFFERENTIAL REGULATION OF 11ß-HYDROXYSTEROID DEHYDROGENASE TYPE 1 ACTIVITY IN PATIENTS WITH DIFFERING ETIOLOGIES OF HYPOPITUITARISM.

OBJECTIVE: Pituitary patients with different etiologies of hypopituitarism exhibit differing phenotypes, despite similar replacement therapy strategies. We hypothesized that differential regulation of the isoenzyme 11ß-hydroxysteroid dehydrogenase 1 (11ß-HSD1), which mediates the net autocrine conversion of cortisone to cortisol in adipose tissues and liver, may play a role. METHODS: We studied 11ß-HSD1 activity (using urine cortisol/cortisone metabolites ratio) in 36 hypopituitary patients with treated craniopharyngiomas, treated remitted Cushing disease, and treated nonfunctioning pituitary adenomas + prolactinomas on and off growth hormone (GH) replacement. RESULTS: 11ß-HSD1 activity was higher in subjects with craniopharyngioma both on and off GH, as evidenced by increased tetrahydrocortisol to tetrahydrocortisone metabolite ratios compared to other diagnostic groups, but there was no difference in body mass index, insulin levels, serum hormone measurements, or hydrocortisone dose between groups. CONCLUSION: Craniopharyngiomas are associated with enhanced 11ß-HSD1 activity compared to other diagnostic hypopituitary groups, and this may contribute to the adverse phenotypic and metabolic features seen in this condition. ABBREVIATIONS: BMI = body mass index; Em = cortisone metabolites; Fm = cortisol metabolites; GH = growth hormone; 11ß-HSD1 = 11ß-hydroxysteroid dehydrogenase type 1; IGF-1 = insulin-like growth factor 1; NFPA = nonfunctioning pituitary adenoma; THE = tetrahydrocortisone; THF = tetrahydrocortisol.

Assessment of Hepatic Cytochrome P450 3A Activity Using Metabolic Markers in Patients with Renal Impairment.

BACKGROUND: The renal function of individuals is one of the reasons for the variations in therapeutic response to various drugs. Patients with renal impairment are often exposed to drug toxicity, even with drugs that are usually eliminated by hepatic metabolism. Previous study has reported an increased plasma concentration of indoxyl sulfate and decreased plasma concentration of 4ß-hydroxy (OH)-cholesterol in stable kidney transplant recipients, implicating indoxyl sulfate as a cytochrome P450 (CYP) inhibiting factor. In this study, we aimed to evaluate the impact of renal impairment severity-dependent accumulation of indoxyl sulfate on hepatic CYP3A activity using metabolic markers. METHODS: Sixty-six subjects were enrolled in this study; based on estimated glomerular filtration rate (eGFR), they were classified as having mild, moderate, or severe renal impairment. The plasma concentration of indoxyl sulfate was quantified using liquid chromatography-mass spectrometry (LC-MS). Urinary and plasma markers (6ß-OH-cortisol/cortisol, 6ß-OH-cortisone/cortisone, 4ß-OH-cholesterol) for hepatic CYP3A activity were quantified using gas chromatography-mass spectrometry (GC-MS). The total plasma concentration of cholesterol was measured using the enzymatic colorimetric assay to calculate the 4ß-OH-cholesterol/cholesterol ratio. The correlation between variables was assessed using Pearson's correlation test. RESULTS: There was a significant negative correlation between MDRD eGFR and indoxyl sulfate levels. The levels of urinary 6ß-OH-cortisol/cortisol and 6ß-OH-cortisone/cortisone as well as plasma 4ß-OH-cholesterol and 4ß-OH-cholesterol/cholesterol were not correlated with MDRD eGFR and the plasma concentration of indoxyl sulfate. CONCLUSION: Hepatic CYP3A activity may not be affected by renal impairment-induced accumulation of plasma indoxyl sulfate.

Diagnostic accuracy of increased urinary cortisol/cortisone ratio to differentiate ACTH-dependent Cushing's syndrome.

BACKGROUND AND AIM: Differential diagnosis between Cushing's Disease (CD) and Ectopic ACTH Syndrome (EAS) may be a pitfall for endocrinologists. The increasing use in clinical practice of chromatography and mass spectrometry improves the measurement of urinary free cortisol (UFF) and cortisone (UFE). We have recently observed that cortisol to cortisone ratio (FEr) was higher in a small series of EAS; in this study we collected a larger number of ACTH-dependent Cushing's Syndrome (CS) to study the role of FEr to characterize the source of corticotropin secretion. MATERIALS AND METHODS: High-pressure liquid chromatography with UV detection (HPLC-UV, n=35) or liquid chromatography-tandem mass spectrometry (LC-MS/MS, n=72) were used to measure UFF, UFE and FEr in 83 patients with CD and 24 with EAS. RESULTS: UFF, UFE and FEr levels were higher in EAS than in CD (UFF: 6671 vs 549 nmol/24 hours; UFE: 2069 vs 464 nmol/24 hours; FEr: 4.13 vs 0.97; all P<.001). FEr >1.15 (the best ROC-based threshold) was able to distinguish CD from EAS with 75% sensitivity (SE) and 75% specificity (SP), AUC 0.811; results were similar between HPLC-UV (SE 73%, SP 79%, AUC 0.708) and LC-MS/MS (SE 77%, SP 73%, AUC 0.834; P=.727). The diagnostic accuracy of FEr was similar to that of CRH test or high-dose dexamethasone suppression test (respectively P=.171 and P=.683), also combined. Finally, FEr was able to increase the number of correct diagnosis in patients with discordant dynamic tests. CONCLUSIONS: Urinary FEr >1.15 was able to suggest EAS, with a diagnostic accuracy similar to that of other dynamic tests proposed to study ACTH-dependent CS.

Study on cortisol, cortisone and prednisolone presence in urine of Chianina cattle breed.

The Chianina, one of the oldest and most important cattle breeds of Italy, is now reared all over the world. The Chianina has been known and appreciated since ancient times because, from a nutritional point of view, its meat has no proper rivals. To date, studies have been performed to evaluate the genetic profile of the breed, but knowledge about the chemical profile is generally lacking. Due to the increased interest from farmers regarding breeding of the Chianina, this study proposes a preliminary evaluation of main endogenous urinary corticosteroids (cortisol and cortisone) and most commonly used synthetic one (dexamethasone). Moreover, after recent findings regarding the presence of endogenous prednisolone in the urine of more popular breeds, particular attention was given to analysis of the presence of prednisolone and prednisone, as well. For this aim, the urine samples of 12 young cows and 30 young bulls was collected at the farms and analysed using a fit-for-purpose LC-MS/MS method. The preliminary results of this study show that prednisolone was found only in Chianina females (3 out of 12). Cortisol and cortisone were found at concentrations that showed a high inter-individual variability, and that were higher in female urine compared to that of males.

Higher diet-dependent renal acid load associates with higher glucocorticoid secretion and potentially bioactive free glucocorticoids in healthy children.

Metabolic acidosis induces elevated glucocorticoid (GC) levels. However, the influence of less strong daily acid loads on GCs is largely unexplored. To investigate this, we studied whether higher acid loads in children, fully within the normal range of habitual diets, associate with endogenous GCs. In a specific quasi-experimental design, we examined 200 6- to 10-year-old healthy participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study equally divided to either high or low 24-hour renal net acid excretion. Major urinary GC metabolites were analyzed by gas chromatography-mass spectrometry to assess daily adrenal GC secretion and metabolites of tissue cortisol catabolism (6ß-hydroxycortisol and 20α-dihydrocortisol). Liquid chromatography-mass spectrometry was used to quantify urinary free cortisol and cortisone. After confounder adjustment, significant positive associations were unmasked for urinary potential renal acid load and net acid excretion with adrenal GC secretion, free cortisone, free cortisone plus cortisol, 6ß-hydroxycortisol, and 20α-dihydrocortisol. An inverse association emerged for an enzymatic marker (5ß-reductase) of irreversible GC inactivation. Our data suggest that existing moderate elevations in diet-dependent acid loads suffice to raise GCs and affect cortisol metabolism. Thus, potential detrimental effects of high acid loading appear to be mediated, in part, by increased GC activity via increased GC secretion and/or reduced GC inactivation. Higher cortisone levels, directly available for intracrine activation to cortisol may play a special role.

Prediction of tacrolimus metabolism and dosage requirements based on CYP3A4 phenotype and CYP3A5(*)3 genotype in Chinese renal transplant recipients.

AIM: To examine how the endogenous CYP3A4 phenotype and CYP3A5(*)3 genotype of Chinese renal transplant recipients influenced the dose-corrected trough concentration (C0/D) and weight-corrected daily dose (D/W) of tacrolimus. METHODS: A total of 101 medically stable kidney transplant recipients were enrolled, and their blood and urine samples were gathered. The endogenous CYP3A4 phenotype was assessed by the ratio of 6ß-hydroxycortisol and 6ß-hydroxycortisone to cortisol and cortisone in urine. CYP3A5(*)3 genotype was determined using PCR-RELP. RESULTS: In overall renal transplant recipients, a multiple regression analysis including the endogenous CYP3A4 phenotype, CYP3A5(*)3 genotype and post-operative period accounted for 60.1% of the variability in C0/D ratio; a regression equation consisting of the endogenous CYP3A4 phenotype, post-operative period, body mass index, CYP3A5(*)3 genotype, gender, total bilirubin and age explained 61.0% of the variability in D/W ratio. In CYP3A5(*)3/(*)3 subjects, a combination of the endogenous CYP3A4 phenotype, post-operative period and age was responsible for 65.3% of the variability in C0/D ratio; a predictive equation including the endogenous CYP3A4 phenotype, post-operative period, body mass index, gender and age explained 61.2% of the variability in the D/W ratio. Base on desired target range of tacrolimus trough concentrations, individual daily dosage regimen was calculated, and all the observed daily doses were within the predicted range. CONCLUSION: This study provides the equations to predict tacrolimus metabolism and dosage requirements based on the endogenous CYP3A4 phenotype, CYP3A5(*)3 genotype and other non-genetic variables.

Reduction in cortisol inactivation is part of the adrenal stress response to cardiac and noncardiac pediatric surgery: a prospective study using gas chromatography-mass spectrometry analysis.

We examined the hypothesis that major cardiac surgery triggers a more intense adrenal stress response than less intensive noncardiac surgery, which then alters cortisol inactivation. Urinary excretion rates of glucocorticoid metabolites were determined before and after surgery using gas chromatography-mass spectrometry in 29 children undergoing scheduled major cardiac surgery and 17 control children undergoing conventional noncardiac surgery in a prospective observational study. Excretion rates of glucocorticoid metabolites were summed and corrected for creatinine excretion to calculate cortisol production rates (mg/mmol creatinine/m(2) body surface area). Precursor/product ratios from individual metabolites were calculated to characterize cortisol inactivation (11ß-hydroxysteroid dehydrogenase). Postoperatively, median cortisol production rates increased in both groups ( MCS: from 2.7 to 9.3; controls: from 2.7 to 5.8; p<0.001) with no significant difference between groups (p=0.12). Ratios of cortisol to cortisone metabolites, indicating the overall activity of 11ß-hydroxysteroid dehydrogenase, increased postoperatively in both groups (p<0.001). In conclusion, surgery resulted in a distinct postoperative increase in cortisol production. In contrast to our hypothesis, children undergoing major cardiac surgery did not show an increased adrenal stress response compared to children undergoing conventional surgery. Furthermore, the reduction in cortisol inactivation appears to be an essential part of the stress response to pediatric surgery in general.

Cortisol and cortisone ratio in urine: LC-MS/MS method validation and preliminary clinical application.

BACKGROUND: The determination of urinary cortisol/cortisone ratio is of clinical utility in cases of Cushing's syndrome, apparent mineralocorticoid excess, and also provides information on 11ß-hydroxysteroid dehydrogenase (11ß-HSD) type 2 activity. It is therefore of utmost importance to ensure accurate cortisol and cortisone measurement and establish appropriate reference ranges. METHODS: After the isotopic dilution of urine, sample cleanups were obtained with on-line solid-phase extraction and cortisol and cortisone, separated using a Zorbax Eclipse XDB-C18 HPLC analytical column, were analyzed by tandem mass spectrometry with an electrospray ionization source in positive ion mode operation. RESULTS: The method was linear, with concentrations of up to 625 and 1125 nmol/L and lower limit of quantitation (LLOQ) of 5 and 6 nmol/L, for cortisol and cortisone, respectively. Within-run and between-run coefficients of variation were <5% and 6% for cortisol and 6% and 8% for cortisone, respectively. No ion suppression was observed. The non-parametric reference range for the cortisol/cortisone ratio was 0.14-1.09. CONCLUSIONS: A simple and sensitive liquid chromatography tandem mass spectrometry method was developed and validated for the measurement of cortisol and cortisone in urine. Our findings indicate that the proposed analytical method is suitable for routine purposes and useful in many pathological conditions.

Determination of free cortisol and free cortisone in human urine by on-line turbulent flow chromatography coupled to fused-core chromatography-tandem mass spectrometry (TFC-HPLC-MS/MS).

Urinary free cortisol and urinary free cortisone are decisive markers for the diagnosis of syndromes related to the dysfunction of the adrenal gland or to evaluate certain enzymatic disorders. Here, we present a new method, designed for routine laboratory use, which enables quick determination of these analytes with minor sample workup. Turbulent flow chromatography shortens sample preparation, and connection to a fused-core particle-packed column (rugged amide-embedded C18 phase) permits a rapid and effective separation of the analytes, as well as additional separation from other related and isobaric compounds present in urine. Urinary isobaric compounds were successfully identified. The method requires only 100 µl of urine supernatant per sample. The total time between injections is 9.5 min. The solvents used for both turbulent and analytical chromatography are water and methanol, and the relatively low flows needed during the method resulted in an extended life of the columns. Linearity showed a R (2) > 0.994. Limit of detection and limit of quantification are 0.5 and 1.0 ng/ml for cortisone and 1.0 and 2.0 ng/ml for cortisol. Recoveries ranged from 99.7 to 109.1 % for cortisone and from 98.7 to 102.9 % for cortisol. Accuracy values (relative errors) for intra- and inter-assay experiments were always below 8 %, whereas precision (percent CV) ranged from 3.7 to 10.7 %. No matrix effects were detected during the validation process. The reproducibility for each analyte's retention time was excellent, with a coefficient of variation always below 0.2 %. The final validation step included the study of urine samples from healthy children and from children previously diagnosed with corticoidal disorders. The high selectivity achieved enables quick data handling.

LC-HRMS and GC-MS Profiling of Urine Free Cortisol, Cortisone, 6Β-, and 18-Hydroxycortisol for the Evaluation of Glucocorticoid and Mineralocorticoid Disorders.

INTRODUCTION: Urine free cortisol measurements are routinely performed to evaluate hypercortisolism. Despite their analytical inaccuracy, immunoassay-based methods are frequently used. Advances in liquid chromatography-high-resolution mass spectrometry (LC-HRMS) facilitate the incorporation of powerful diagnostic tools into clinical laboratories. In addition to its high analytical specificity and simultaneous analysis of different metabolites, accurate mass measurement allows for untargeted compound identification, which may help to identify clinically relevant metabolites or drugs. METHODS: The present study aimed to validate a simple routine LC-HRMS method to quantify cortisol, cortisone, 6ß-hydroxycortisol, and 18-hydroxycortisol simultaneously in human urine. Additionally, the study also validated a GC-MS method for the same steroids, evaluated their cross-reactivity with commercial cortisol immunoassays, and quantified the 24 h urine excretion in patients under clinical suspicion or follow-up for hypercortisolism. RESULTS: The LC-HRMS method involved liquid-liquid extraction using dichloromethane, micro-LC for chromatographic separation and detection using the accurate masses of the steroids, and simultaneous high-resolution full scan acquisition. The method presented acceptable linearity, precision, and accuracy. Significant interference from 6ß-hydroxycortisol and cortisone was demonstrated in the cortisol immunoassays, which impacted their reliability in the follow-up of patients with hypercortisolism and significant changes in these cortisol metabolites (i.e., due to drug-induced changes in CYP3A4 activity). CONCLUSION: A rapid and accurate routine LC-HRMS method was validated, which is useful for the evaluation of hypercortisolism and other disorders of glucocorticoid and mineralocorticoid metabolism.

Effects of sodium intake, age, gender, blood sampling time on distribution of plasma aldosterone, renin activity, deoxycorticosterone, cortisol, cortisone, and 24 h urinary aldosterone levels in normotensive individuals based on LC-MS/MS.

PURPOSE: This study aims to analyze the distribution of plasma aldosterone, renin activity, deoxycorticosterone (DOC), cortisol, cortisone, and 24 h urinary aldosterone (24 h-uAld) levels based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. MATERIALS AND METHODS: Plasma and 24 h urine were collected from 129 healthy volunteers in Northeast China. The effect of sodium intake, age, gender, blood sampling time on plasma aldosterone concentration (PAC), plasma renin activity (PRA), PAC to PRA ratio (ARR), DOC, cortisol, cortisone, cortisol to cortisone ratio, and 24 h-uAld were investigated by nonparametric test, multiple linear regression and Harris-Boyd's standard deviate test. RESULTS: There was no significant difference observed in 24 h-uAld, PAC (AM), PRA(AM), ARR (AM), DOC (AM), cortisol (AM), cortisone (AM), and cortisol to cortisone (AM) between high and low sodium intake group. Significant differences were observed between morning and afternoon sampling groups in terms of PAC, ARR, DOC, cortisol, and cortisone. Reference intervals (RIs) of 24 h-uAld, PAC (AM) were recommended to be partitioned by gender. RI of PRA was recommended age stratification. CONCLUSION: We recommend that the same reference interval could be used regardless of sodium intake. Gender is the main influence factor for 24 h-uAld, PAC, and ARR. Age is key influence factor for PRA.

Primary male osteoporosis is associated with enhanced glucocorticoid availability.

OBJECTIVE: While systemic glucocorticoids compromise bone metabolism, altered intracellular cortisol availability may also contribute to the pathogenesis of primary male osteoporosis (MO). The objective of this study was to assess whether intracellular cortisol availability is increased in MO due to a distorted local cortisol metabolism. METHODS: Forty-one patients with MO were compared with age- and BMI-matched non-osteoporotic subjects after excluding overt systemic hypercortisolism (N = 41). Cortisol, cortisone and the respective tetrahydro-, 5α-tetrahydro- and total cortisol metabolites were analysed by GC-MS in 24 h urine. Apparent 11ß-hydroxysteroid dehydrogenase (11ß-HSD) enzyme activities, excretion of cortisol metabolites and calcium, and fractional urinary calcium excretion were assessed and related to BMD. RESULTS: Fractional and total urinary calcium excretion negatively correlated with BMD at all (P < 0.05) and at three of five (P < 0.05) measurement sites, respectively. While systemic cortisol was unchanged, apparent 11ß-HSD enzyme activity in MO patients (P < 0.01) suggested increased intracellular cortisol availability. Total and fractional urinary calcium excretion was higher, with apparent 11ß-HSD enzyme activities consistent with an enhanced intracellular cortisol availability (P < 0.05). CONCLUSION: Apparent 11ß-HSD enzyme activities consistent with increased intracellular cortisol availability correlated with urinary calcium loss and reduced bone mineral density in MO. The changes in 11ß-HSD activity were associated with both the fractional calcium excretion, suggesting altered renal calcium handling, and the absolute urinary calcium excretion. Both mechanisms could result in a marked bone calcium deficiency if insufficiently compensated for by intestinal calcium uptake.

Cortisol metabolism after weight loss: associations with 11 ß-HSD type 1 and markers of obesity in women.

OBJECTIVE: Increased glucocorticoid metabolite excretion and enhanced expression and activity of 11ß-hydroxysteroid dehydrogenase type 1 in adipose tissue are closely correlated with obesity and its detrimental consequences. Weight loss ameliorates the latter. The aim of this study was to explore whether increased glucocorticoid exposure in obesity is improved with substantial weight loss and thus is a consequence rather than a cause of obesity. DESIGN AND PATIENTS: A prospective cohort study in 31 women. MEASUREMENTS: 11ß-HSD type 1 expression and activity, urinary glucocorticoid metabolite excretion, body composition including regional adipose tissue depots and insulin resistance by HOMA-IR before and 2 years after gastric bypass surgery. RESULTS: After weight loss, excretion of cortisol and cortisone metabolites decreased. Both cortisol and cortisone metabolite excretion correlated with central obesity, where the intraabdominal fat depot showed the strongest association. Cortisol metabolites correlated with 11ß-HSD type 1 activity in abdominal subcutaneous adipose tissue. The ratio of cortisol to cortisone metabolites [(5α-tetrahydrocortisol (5αTHF) + tetrahydrocortisol (THF) + α-cortol)/(tetrahydrocortisone (THE) + α-cortolone)] and the ratio of 5α-THF/THF both decreased after stable weight loss, reflecting a downregulation of the net activities of 11ß-HSD type 1 and 5α-reductase. CONCLUSION: Long-term weight loss in women is not only followed by reduced glucocorticoid production, but also favourably decreases the global and tissue-specific activity of the cortisol-activating enzyme 11 ß-HSD type 1, possibly contributing to the health benefits of bariatric surgery.

Longer HSD11B2 CA-repeat in impaired glucose tolerance and type 2 diabetes.

Type 2 11ß-hydroxysteroid dehydrogenase encoded by the HSD11B2 gene converts cortisol to inactive cortisone, and alteration in this enzymatic activity might affect glucose homeostasis by affecting circulating levels or tissue availability of glucocorticoids. We investigated the association of HSD11B2 variant with glucose homeostasis. Subjects with normal glucose tolerance (n=585), impaired glucose tolerance (n=202) and type 2 diabetes (n=355) were genotyped for a highly polymorphic CA-repeat polymorphism in the first intron of HSD11B2. Allele and genotype frequencies differed between normal and impaired glucose tolerance (P = 0.0014 and 0.0407, respectively; 4 degree of freedom) or type 2 diabetes (P = 0.0053 and 0.0078), with significant linear trends between the repeat length and the phenotype fraction. In normal subjects, total CA-repeat length was negatively correlated with fasting insulin and HOMA-ß. Thus, subjects having more CA repeats are susceptible to developing abnormal glucose tolerance, whereas normal subjects carrying more CA repeats appeared to have frugal characteristics in insulin secretion.

Chemometric evaluation of urinary steroid hormone levels as potential biomarkers of neuroendocrine tumors.

Neuroendocrine tumors (NETs) are uncommon tumors which can secrete specific hormone products such as peptides, biogenic amines and hormones. So far, the diagnosis of NETs has been difficult because most NET markers are not specific for a given tumor and none of the NET markers can be used to fulfil the criteria of high specificity and high sensitivity for the screening procedure. However, by combining the measurements of different NET markers, they become highly sensitive and specific diagnostic tests. The aim of the work was to identify whether urinary steroid hormones can be identified as potential new biomarkers of NETs, which could be used as prognostic and clinical course monitoring factors. Thus, a rapid and sensitive reversed-phase high-performance liquid chromatographic method (RP-HPLC) with UV detection has been developed for the determination of cortisol, cortisone, corticosterone, testosterone, epitestosterone and progesterone in human urine. The method has been validated for accuracy, precision, selectivity, linearity, recovery and stability. The limits of detection and quantification were 0.5 and 1 ng mL-1 for each steroid hormone, respectively. Linearity was confirmed within a range of 1-300 ng mL-1 with a correlation coefficient greater than 0.9995 for all analytes. The described method was successfully applied for the quantification of six endogenous steroid levels in human urine. Studies were performed on 20 healthy volunteers and 19 patients with NETs. Next, for better understanding of tumor biology in NETs and for checking whether steroid hormones can be used as potential biomarkers of NETs, a chemometric analysis of urinary steroid hormone levels in both data sets was performed.

Biomedical evaluation of cortisol, cortisone, and corticosterone along with testosterone and epitestosterone applying micellar electrokinetic chromatography.

The validated micellar electrokinetic chromatography (MEKC) was proposed for the determination of five steroid hormones in human urine samples. That technique allowed for the separation and quantification of cortisol, cortisone, corticosterone, testosterone, and epitestosterone and was sensitive enough to detect low concentrations of these searched steroids in urine samples at the range of 2-300 ng/mL. The proposed MEKC technique with solid-phase extraction (SPE) procedure was simple, rapid, and has been successfully applied as a routine procedure to analyze steroids in human urine samples. The MEKC method offered a potential in clinical routine practice because of the short analysis time (8 min), low costs, and simultaneous analysis of five endogenous hormones. Due to its simplicity, speed, accuracy, and high recovery, the proposed method could offer a tool to determine steroid hormones as potential biomarkers in biomedical investigations, what was additionally revealed with healthy volunteers.