Hypertension in a four-year-old child: gas chromatographic and mass spectrometric evidence for deficient hepatic metabolism of steroids

Genetics of Hypertension: From Monogenic Analysis to GETomics

Arterial hypertension is the most frequent cardiovascular risk factor all over the world, and it is one of the leading drivers of the risk of cardiovascular events and death. It is a complex trait influenced by heritable and environmental factors. To date, the World Health Organization estimates that 1.28 billion adults aged 30-79 years worldwide have arterial hypertension (defined by European guidelines as office systolic blood pressure ≥ 140 mmHg or office diastolic blood pressure ≥ 90 mmHg), and 7.1 million die from this disease. The molecular genetic basis of primary arterial hypertension is the subject of intense research and has recently yielded remarkable progress. In this review, we will discuss the genetics of arterial hypertension. Recent studies have identified over 900 independent loci associated with blood pressure regulation across the genome. Comprehending these mechanisms not only could shed light on the pathogenesis of the disease but also hold the potential for assessing the risk of developing arterial hypertension in the future. In addition, these findings may pave the way for novel drug development and personalized therapeutic strategies.

Clinical and Molecular Perspectives of Monogenic Hypertension

Advances in molecular research techniques have enabled a new frontier in discerning the mechanisms responsible for monogenic diseases. In this review, we discuss the current research on the molecular pathways governing blood pressure disorders with a Mendelian inheritance pattern, each presenting with a unique pathophysiology. Glucocorticoid Remediable Aldosteronism (GRA) and Apparent Mineralocorticoid Excess (AME) are caused by mutations in regulatory enzymes that induce increased production of mineralocorticoids or inhibit degradation of glucocorticoids, respectively. Geller syndrome is due to a point mutation in the hormone responsive element of the promotor for the mineralocorticoid receptor, rendering the receptor susceptible to activation by progesterone, leading to hypertension during pregnancy. Pseudohypoaldosteronism type II (PHA-II), also known as Gordon's syndrome or familial hyperkalemic hypertension, is a more variable disorder typically characterized by hypertension, high plasma potassium and metabolic acidosis. Mutations in a variety of intracellular enzymes that lead to enhanced sodium reabsorption have been identified. In contrast, hypertension in Liddle's syndrome, which results from mutations in the Epithelial sodium Channel (ENaC), is associated with low plasma potassium and metabolic alkalosis. In Liddle's syndrome, truncation of one the ENaC protein subunits removes a binding site necessary protein for ubiquitination and degradation, thereby promoting accumulation along the apical membrane and enhanced sodium reabsorption. The myriad effects due to mutation in phosphodiesterase 3A (PDE3A) lead to severe hypertension underlying sodium-independent autosomal dominant hypertension with brachydactyly. How mutations in PDE3A result in the phenotypic features of this disorder are discussed. Understanding the pathologies of these monogenic hypertensive disorders may provide insight into the causes of the more prevalent essential hypertension and new avenues to unravel the complexities of blood pressure regulation.

Steroid Metabolome Analysis in Disorders of Adrenal Steroid Biosynthesis and Metabolism

Steroid biosynthesis and metabolism are reflected by the serum steroid metabolome and, in even more detail, by the 24-hour urine steroid metabolome, which can provide unique insights into alterations of steroid flow and output indicative of underlying conditions. Mass spectrometry-based steroid metabolome profiling has allowed for the identification of unique multisteroid signatures associated with disorders of steroid biosynthesis and metabolism that can be used for personalized approaches to diagnosis, differential diagnosis, and prognostic prediction. Additionally, steroid metabolome analysis has been used successfully as a discovery tool, for the identification of novel steroidogenic disorders and pathways as well as revealing insights into the pathophysiology of adrenal disease. Increased availability and technological advances in mass spectrometry-based methodologies have refocused attention on steroid metabolome profiling and facilitated the development of high-throughput steroid profiling methods soon to reach clinical practice. Furthermore, steroid metabolomics, the combination of mass spectrometry-based steroid analysis with machine learning-based approaches, has facilitated the development of powerful customized diagnostic approaches. In this review, we provide a comprehensive up-to-date overview of the utility of steroid metabolome analysis for the diagnosis and management of inborn disorders of steroidogenesis and autonomous adrenal steroid excess in the context of adrenal tumors.

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

11β-hydroxysteroid dehydrogenases: intracellular gate-keepers of tissue glucocorticoid action

Glucocorticoid action on target tissues is determined by the density of "nuclear" receptors and intracellular metabolism by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) which catalyze interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone. 11β-HSD type 1, a predominant reductase in most intact cells, catalyzes the regeneration of active glucocorticoids, thus amplifying cellular action. 11β-HSD1 is widely expressed in liver, adipose tissue, muscle, pancreatic islets, adult brain, inflammatory cells, and gonads. 11β-HSD1 is selectively elevated in adipose tissue in obesity where it contributes to metabolic complications. Similarly, 11β-HSD1 is elevated in the ageing brain where it exacerbates glucocorticoid-associated cognitive decline. Deficiency or selective inhibition of 11β-HSD1 improves multiple metabolic syndrome parameters in rodent models and human clinical trials and similarly improves cognitive function with ageing. The efficacy of inhibitors in human therapy remains unclear. 11β-HSD2 is a high-affinity dehydrogenase that inactivates glucocorticoids. In the distal nephron, 11β-HSD2 ensures that only aldosterone is an agonist at mineralocorticoid receptors (MR). 11β-HSD2 inhibition or genetic deficiency causes apparent mineralocorticoid excess and hypertension due to inappropriate glucocorticoid activation of renal MR. The placenta and fetus also highly express 11β-HSD2 which, by inactivating glucocorticoids, prevents premature maturation of fetal tissues and consequent developmental "programming." The role of 11β-HSD2 as a marker of programming is being explored. The 11β-HSDs thus illuminate the emerging biology of intracrine control, afford important insights into human pathogenesis, and offer new tissue-restricted therapeutic avenues.

Role of a disordered steroid metabolome in the elucidation of sterol and steroid biosynthesis

In 1937 Butler and Marrian found large amounts of the steroid pregnanetriol in urine from a patient with the adrenogenital syndrome, a virilizing condition known to be caused by compromised adrenal secretion even in this pre-cortisol era. This introduced the concept of the study of altered excretion of metabolites as an in vivo tool for understanding sterol and steroid biosynthesis. This approach is still viable and has experienced renewed significance as the field of metabolomics. From the first cyclized sterol lanosterol to the most downstream product estradiol, there are probably greater than 30 steps. Based on a distinctive metabolome clinical disorders have now been attributed to about seven post-squalene cholesterol (C) biosynthetic steps and around 15 en-route to steroid hormones or needed for further metabolism of such hormones. Forty years ago it was widely perceived that the principal steroid biosynthetic defects were known but interest rekindled as novel metabolomes were documented. In his career this investigator has been involved in the study of many steroid disorders, the two most recent being P450 oxidoreductase deficiency and apparent cortisone reductase deficiency. These are of interest as they are due not to mutations in the primary catalytic enzymes of steroidogenesis but in ancillary enzymes needed for co-factor oxido-reduction A third focus of this researcher is Smith-Lemli-Opitz syndrome (SLOS), a cholesterol synthesis disorder caused by 7-dehydrocholesterol reductase mutations. The late George Schroepfer, in whose honor this article has been written, contributed greatly to defining the sterol metabolome of this condition. Defining the cause of clinically severe disorders can lead to improved treatment options. We are now involved in murine gene therapy studies for SLOS which, if successful could in the future offer an alternative therapy for this severe condition.

11β-hydroxysteroid dehydrogenases and the brain: from zero to hero, a decade of progress

Glucocorticoids have profound effects on brain development and adult CNS function. Excess or insufficient glucocorticoids cause myriad abnormalities from development to ageing. The actions of glucocorticoids within cells are determined not only by blood steroid levels and target cell receptor density, but also by intracellular metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSD). 11β-HSD1 regenerates active glucocorticoids from their inactive 11-keto derivatives and is widely expressed throughout the adult CNS. Elevated hippocampal and neocortical 11β-HSD1 is observed with ageing and causes cognitive decline; its deficiency prevents the emergence of cognitive defects with age. Conversely, 11β-HSD2 is a dehydrogenase, inactivating glucocorticoids. The major central effects of 11β-HSD2 occur in development, as expression of 11β-HSD2 is high in fetal brain and placenta. Deficient feto-placental 11β-HSD2 results in a life-long phenotype of anxiety and cardiometabolic disorders, consistent with early life glucocorticoid programming.

Monogenic low renin hypertension

Monogenic forms of low renin hypertension can now be identified in a large and heterogeneous family of hypertensive patients with highly specific etiologies and similar clinical manifestations. These include the following well-characterized disorders: apparent mineralocorticoid excess, Liddle's Syndrome, steroid 11beta-hydroxylase (11beta-OHD) and steroid 17-hydroxylase (17-OHD) deficiencies, glucocorticoid-remediable hyperaldosteronism (familial hyperaldosteronism type I), familial hyperaldosteronism type II, hypertension exacerbated by pregnancy and primary hyperaldosteronism (Conn's syndrome). The successful elucidation of specific DNA mutations in most of these conditions has emphasized the role of molecular genetics in hypertension, a field in which diagnosis can now be made on proven genetic evidence. The current knowledge of these genetic markers enables practitioners to make precise diagnoses, and to initiate specific therapy, in patients with these relatively uncommon but interesting and often treatable forms of hypertension.

Measuring tobacco smoke exposure: quantifying nicotine/cotinine concentration in biological samples by colorimetry, chromatography and immunoassay methods

Procedures to assess tobacco smoke exposure are reviewed and biomarkers used for determining the smoking status of an individual are compared. Methods used to extract these biomarkers from saliva, urine, and blood and the advantages and disadvantages of the assays are discussed. Finally, the procedures used to measure the levels of cortisol, a stress hormone speculated to be linked to nicotine metabolism, are discussed.

Simultaneous determination of 6β-hydroxycortisol and cortisol in human urine by liquid chromatography with ultraviolet absorbance detection for phenotyping the CYP3A activity determined by the cortisol 6β-hydroxylation clearance

This study describes a high-performance liquid chromatographic (HPLC) method for the simultaneous determination of 6beta-hydroxycortisol (6beta-OHF) and cortisol in human urine using either methylprednisolone or beclomethasone as internal standard. Separation was achieved on a reversed-phase phenyl column by a gradient elution of 0.05 M KH(2)PO(4)-0.01 M CH(3)COOH (pH 3.77) and 0.05 M KH(2)PO(4)-0.01 M CH(3)COOH with acetonitrile (4:6, v/v). 6beta-Hydroxycortisol and cortisol were monitored by UV absorption at 239 nm. The lower quantitation limits of the present HPLC method were 21.5 ng/ml for 6beta-OHF and 5.0 ng/ml for cortisol in urine. The within-day reproducibilities in the amounts of 6beta-OHF and cortisol determined were in good agreement with the actual amounts added, the relative error being less than 1.59%. The inter-assay precisions (R.S.D. values) were less than 7.91% for 6beta-OHF and cortisol. The method was compared with the GC/MS method by measuring 6beta-OHF in the same urine samples. A good correlation was found between the amounts determined by the two methods. The regression equations for the HPLC (y) and GC/MS (x) methods were: y=1.0701x+17.389 (r=0.9772) for methylprednisolone as internal standard and y=1.0827x+6.1364 (r=0.9794) for beclomethasone as internal standard.

Urinary steroid profile analysis

BACKGROUND

A detailed analysis (profile) of the steroid metabolites in urine is useful for diagnosis of adrenal problems. Hospitals from many of UK health regions and around the world use the specialist assay and advisory service at UCLH. According to the total workload, samples are from patients with precocious puberty/premature adrenarche (21%), ambiguous genitalia (17%), Cushing's syndrome (13%), tumors (11%), polycystic ovaries (9%), hypertension (6%), problems of growth and development (5%), salt-loss (3%) and male pseudohermaphroditism (3%). Sixty percent of samples are from children and comprehensive reference data for steroid excretion rates in childhood unique to this laboratory were essential for interpretation of the results.

CONCLUSION

The recognition and high excretion rates of certain steroids not easily measured in blood or urine by any other assays was particularly in cases of hypertension and tumors. The assay is cost effective by comparison with the combined costs of several individual hormone measurements but that cost may delay early referral to a specialist centre and that is not in the best interests of the families involved.

Apparent mineralocorticoid excess

Apparent mineralocorticoid excess (AME) is a potentially fatal genetic disorder causing severe juvenile hypertension, pre- and postnatal growth failure, hypokalemia and low to undetectable levels of renin and aldosterone. It is caused by autosomal recessive mutations in the HSD11B2 gene, which result in a deficiency of 11 beta-hydroxysteroid dehydrogenase type 2 (11 beta-HSD2). The 11 beta-HSD2 enzyme is responsible for the conversion of cortisol to the inactive metabolite cortisone and, therefore, protects the mineralocorticoid receptors from cortisol intoxication. In 1998, a mild form of this disease was reported, which might represent an important cause of low-renin hypertension. Early and vigilant treatment might prevent or improve the morbidity and mortality of end-organ damage.

Simultaneous determination of endogenous and 13C-labelled cortisols and cortisones in human plasma by stable isotope dilution mass spectrometry

This study describes a capillary GC-MS method for the simultaneous determination of endogenous cortisol and cortisone and their 13C-labelled analogues, [1,2,4,19-13C4]cortisol (cortisol-13C4) and [1,2,4,19-13C4]cortisone (cortisone-13C4), in human plasma. [1,2,4,19-13C4,1,1,19,19,19-2H5]Cortisol (cortisol-13C4,2H5) and [1,2,4,19-13C4,1,1,19,19,19-2H5]cortisone (cortisone-13C4,2H5) were used as analytical internal standards. A double derivatization (bismethylenedioxy-pentafluoropropionate, BMD-PFP) with good GC behavior was employed for the GC-MS analysis of cortisol and cortisone. Quantitation was carried out by selected-ion monitoring of the molecular ions ([M]+*) of the BMD-PFP derivatives of cortisol and cortisone. The sensitivity limit of the present GC-MS-SIM method was found to be 150 pg per injection for cortisol (s/n=5.0) and 50 pg for cortisone (s/n=8.1). The within-day reproducibility in which the amounts of unlabelled and labelled cortisols and cortisones determined were in good agreement with the actual amounts added, the relative errors being less than 3.07%. The inter-assay coefficients of variation (C.V.) were less than 1.80% for unlabelled and labelled cortisols and cortisones.

Steroid disorders in children: congenital adrenal hyperplasia and apparent mineralocorticoid excess

Our research team and laboratories have concentrated on two inherited endocrine disorders, congenital adrenal hyperplasia (CAH) and apparent mineralocorticoid excess, in thier investigations of the pathophysiology of adrenal steroid hormone disorders in children. CAH refers to a family of inherited disorders in which defects occur in one of the enzymatic steps required to synthesize cortisol from cholesterol in the adrenal gland. Because of the impaired cortisol secretion, adrenocorticotropic hormone levels rise due to impairment of a negative feedback system, which results in hyperplasia of the adrenal cortex. The majority of cases is due to 21-hydroxylase deficiency (21-OHD). Owing to the blocked enzymatic step, cortisol precursors accumulate in excess and are converted to potent androgens, which are secreted and cause in utero virilization of the affected female fetus genitalia in the classical form of CAH. A mild form of the 21-OHD, termed nonclassical 21-OHD, is the most common autosomal recessive disorder in humans, and occurs in 1/27 Ashkenazic Jews. Mutations in the CYP21 gene have been identified that cause both classical and nonclassical CAH. Apparent mineralocorticoid excess is a potentially fatal genetic disorder causing severe juvenile hypertension, pre- and postnatal growth failure, and low to undetectable levels of potassium, renin, and aldosterone. It is caused by autosomal recessive mutations in the HSD11B2 gene, which result in a deficiency of 11beta-hydroxysteroid dehydrogenase type 2. In 1998, we reported a mild form of this disease, which may represent an important cause of low-renin hypertension.

Cortisol as a mineralocorticoid in human disease

The type 2 isozyme of 11beta-hydroxysteroid dehydrogenase inactivates cortisol to cortisone and enables aldosterone to bind to the MR. Congenital deficiency of the enzyme results in cortisol-mediated mineralocorticoid excess and arises because of inactivating mutations in the HSD11B2 gene. Inhibition of the enzyme following licorice or carbenoxolone ingestion results in a similar, though milder phenotype and the enzyme is overwhelmed in ectopic ACTH syndrome. Loss of 11beta-HSD2 expression may be important in sodium balance and blood pressure control in some patients with renal disease. Finally, while some studies demonstrate impaired 11beta-HSD activity in broader populations of patients with hypertension, further studies are required to clarify the role of 11beta-HSD2 in 'essential' hypertension.

A genetic defect resulting in mild low-renin hypertension

Severe low-renin hypertension has few known causes. Apparent mineralocorticoid excess (AME) is a genetic disorder that results in severe juvenile low-renin hypertension, hyporeninemia, hypoaldosteronemia, hypokalemic alkalosis, low birth weight, failure to thrive, poor growth, and in many cases nephrocalcinosis. In 1995, it was shown that mutations in the gene (HSD11B2) encoding the 11beta-hydroxysteroid dehydrogenase type 2 enzyme (11beta-HSD2) cause AME. Typical patients with AME have defective 11beta-HSD2 activity, as evidenced by an abnormal ratio of cortisol to cortisone metabolites and by an exceedingly diminished ability to convert [11-3H]cortisol to cortisone. Recently, we have studied an unusual patient with mild low-renin hypertension and a homozygous mutation in the HSD11B2 gene. The patient came from an inbred Mennonite family, and though the mutation identified her as a patient with AME, she did not demonstrate the typical features of AME. Biochemical analysis in this patient revealed a moderately elevated cortisol to cortisone metabolite ratio. The conversion of cortisol to cortisone was 58% compared with 0-6% in typical patients with AME whereas the normal conversion is 90-95%. Molecular analysis of the HSD11B2 gene of this patient showed a homozygous C-->T transition in the second nucleotide of codon 227, resulting in a substitution of proline with leucine (P227L). The parents and sibs were heterozygous for this mutation. In vitro expression studies showed an increase in the Km (300 nM) over normal (54 nM). Because approximately 40% of patients with essential hypertension demonstrate low renin, we suggest that such patients should undergo genetic analysis of the HSD11B2 gene.

Simultaneous determination of tetrahydrocortisol and tetrahydrocortisone in human plasma and urine by stable isotope dilution mass spectrometry

A capillary gas chromatographic-mass spectrometric method for the simultaneous determination of tetrahydrocortisol (THF, 3alpha,11beta,17alpha,21-tetrahydroxy-5beta-preg nane-20-one), allo-tetrahydrocortisol (allo-THF, 3alpha,11beta,17alpha,21-tetrahydroxy-5alpha-pre gnane-20-one) and tetrahydrocortisone (THE, 3alpha,17alpha,21-trihydroxy-5beta-pregnane-11,20-dion e) in human plasma and urine is described. [1,2,3,4,5-2H5]THF (THF-d5), allo-[1,2,3,4,5-2H5]THF (allo-THF-d5) and [1,2,3,4,5-2H5]THE (THE-d5) were used as internal standards. A double derivatization (bismethylenedioxypentafluoropropionate, BMD-PFP) made possible the separation of the three tetrahydrocorticoids with good gas chromatographic behavior. Quantitation was carried out by selected-ion monitoring of the characteristic fragment ions ([M-30]+) of the BMD-PFP derivatives of THF, allo-THF and THE. The sensitivity, specificity, precision and accuracy of the method were demonstrated to be satisfactory for measuring low concentrations of THF, allo-THF and THE in human plasma and urine.

11 beta-Hydroxysteroid dehydrogenase and the syndrome of apparent mineralocorticoid excess

Whereas aldosterone is normally a much stronger mineralocorticoid than cortisol in vivo, mineralocorticoid receptors have identical in vitro affinities for these hormones. The in vivo specificity of the receptors is, at least in part, the result of activity of 11-HSD, an enzyme located in most mineralocorticoid target tissues that converts cortisol to cortisone. Cortisone is not a ligand for the receptor, whereas aldosterone is not a substrate of the enzyme. The syndrome of AME is a rare form of juvenile hypertension in which 11-HSD is defective. This deficiency allows mineralocorticoid receptors to be occupied by cortisol, leading to hypertension, because plasma concentrations of cortisol are much higher than those of aldosterone. Licorice, which contains 11-HSD inhibitors, causes a similar syndrome. There are two known isozymes of 11-HSD. The liver or type I isozyme is expressed at high levels in the liver, has a relatively low affinity for steroids (micromolar Km), catalyzes both dehydrogenation and the reverse reductase reaction, and utilizes NADP+ or NADPH as cofactors. The kidney or type 2 isozyme is expressed at high levels in the kidney and placenta, has a high affinity (nanomolar Km) for steroids, catalyzes only dehydrogenation, and utilizes NAD+ as a cofactor. Mutations in the HSD11B2 (HSD11K) gene encoding the kidney isozyme of 11-HSD have been detected in all kindreds with AME studied thus far. This gene represents a candidate locus for the common, "essential" form of hypertension.

Quantitation of cortisol and related 3-oxo-4-ene steroids in urine using gas chromatography/mass spectrometry with stable isotope-labeled internal standards

A method for the profiling of several important 3-oxo-4-ene urinary steroids is reported. The methodology is combined gas chromatography/mass spectrometry (GC/MS) utilizing stable isotope-labeled internal standards. The following standards were obtained or easily synthesized: [9, 11, 12, 12-2H4]cortisol, [1,2-2H2] and [9, 12, 12-2H2]cortisone, [1,2-2H2]6 beta-hydroxycortisol, and [1,2-2H2]18-hydroxycortisol. We found the following excretions of free steroids for normal adult males and females: cortisol (males mean +/- SD, 35 +/- 13; females mean +/- SD, 23 +/- 13), cortisone (males mean +/- SD, 58 +/- 23; females mean +/- SD, 50 +/- 22), 6 beta-hydroxycortisol (males mean +/- SD, 164 +/- 59; females mean +/- SD, 108 +/- 55), and 18-hydroxycortisol (males mean +/- SD, 148 +/- 55; females mean +/- SD, 71 +/- 30). For 18-hydroxycortisol in particular, the excretions were much higher for males than for females. We found that the larger part of urinary cortisol and cortisone is not free but is released from conjugation by enzymes present in snail digestive juice. Using a pooled urine sample from an equal number of male and female subjects, we found that for cortisol 29% was excreted free, 28% as glucuronide and 43% as other conjugates (probably sulfates). For cortisone 41% was free, 45% beta-glucuronide and 14% as other conjugates. Relatively little (3-8%) of the hydroxylated cortisols were excreted conjugated.

Apparent mineralocorticoid excess: type I and type II

The syndrome of apparent mineralocorticoid excess (AME) is a heritable form of hypertension due to an inborn error of cortisol metabolism and is characterized by hypokalemia and low renin levels despite subnormal or normal levels of aldosterone and other known mineralocorticoids. The syndrome is attributable to congenital deficiency of the enzyme 11 beta-hydroxydehydrogenase (11 beta-HSD), which converts cortisol (F) to biologically inactive cortisone. This results in a prolonged half-life of F, which acts at the kidney level as a potent mineralocorticoid (MC). In fact, both F and aldosterone have similar affinities in vitro for type I MC receptor (MR), and 11 beta-HSD activity protects the MR in vivo from the higher circulating levels of F. The biochemical marker of this disorder is an increased ratio of tetrahydrocortisol (THF) + allo-THF/tetrahydrocortisone (THE) in the urine, which has been found in more than 20 patients described to date, together with evidence of a more general defect in steroid ring A reduction. Only a few cases (the so-called type II form) described in Italy differ from the classic form having a normal THF/THE ratio, but in both forms the ratio of free urinary F/E has recently been found to be similarly high. Dexamethasone is the treatment of choice but is often inadequate in long term control of high blood pressure. Acquired forms of AME are those consequent on abuse of licorice or carbenoxolone, which both inhibit 11 beta-HSD; the latter also inhibits the reverse 11-oxoreductase reaction leading to somewhat different abnormalities of urinary cortisol/cortisone. So far, two isoenzymes of 11 beta-HSD have been purified and cloned; 11 beta-HSD type 1 is NADP-dependent, abundant in liver, lung, and testis, and catalyzes both 11 beta-dehydrogenation and 11 beta-oxoreduction; no mutation in its gene was detected in patients with AME. A second NAD-dependent isoenzyme is present in kidney and placenta and catalyzes dehydrogenation only. Very recently (1995) two groups have independently demonstrated the presence of mutations in its gene, located in chromosome 16q22. New and co-workers found a point mutation in exon 6 of two affected siblings of an Iranian family, while White and co-workers in parallel studies showed point mutations or small deletions in both alleles in nine unrelated patients; importantly, expression studies showed minimal or absent activity for almost all the mutant sequences. No definite mutations have been so far identified in patients with AME type II. AME is thus the third single gene cause of human hypertension to be described, after glucocorticoid remediable aldosteronism in 1992 and Liddle's syndrome in 1994.

Human hypertension caused by mutations in the kidney isozyme of 11 beta-hydroxysteroid dehydrogenase

The syndrome of apparent mineralocorticoid excess (AME) is an inherited form of human hypertension thought to result from a deficiency of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD). This enzyme normally converts cortisol to inactive cortisone and is postulated to thus confer specificity for aldosterone upon the mineralocorticoid receptor. We have analysed the gene encoding the kidney isozyme of 11 beta HSD and found mutations on both alleles in nine of 11 AME patients (eight of nine kindreds). These mutations markedly affect enzymatic activity. They thus permit cortisol to occupy the renal mineralocorticoid receptor and thereby cause sodium retention and hypertension.

Mineralocorticoid hypertension and congenital deficiency of 11 beta-hydroxysteroid dehydrogenase in a family with the syndrome of 'apparent' mineralocorticoid excess

The so-called syndrome of 'apparent mineralocorticoid excess' (AME) is a rare cause of endocrine hypertension thought to result from a defect in the peripheral conversion of cortisol to cortisone. Less than 30 cases have been described. From a consanguineous marriage we present a family comprising 2 and probably 3 affected cases of AME. The index case is a 4-year-old boy with mineralocorticoid hypertension, short stature, failure to thrive, hypokalaemic nephropathy and osteopenia. The ratio of the urinary excretion of tetrahydrocortisone/tetrahydrocortisols was reduced at 0.05 (reference range 1.77-2.11), and the plasma half-life of 3H-11 alpha-cortisol elevated at 152 minutes (reference range 30-50) indicative of severe 11 beta-hydroxysteroid dehydrogenase deficiency. Plasma cortisol concentrations were normal and daily secretion rate reduced. Dexamethasone administration induced a natriuresis in keeping with the observation that cortisol itself is the implicated mineralocorticoid. Treatment with amiloride lowered blood pressure, increased potassium levels, and resulted in an increase in growth rate. The boy's twin brother died at the age of 3.5 years following a trivial diarrhoeal illness and was almost certainly affected. AME was also diagnosed in a younger brother (age 17 months), but both parents are normal. Congenital deficiency of 11 beta-hydroxysteroid dehydrogenase should be considered in any child with mineralocorticoid hypertension and failure to thrive. As cortisol is the 'offending' mineralocorticoid in this condition, the term 'apparent' mineralocorticoid excess is perhaps obsolete.(ABSTRACT TRUNCATED AT 250 WORDS)

Apparent mineralocorticoid excess syndromes

Apparent mineralocorticoid excess (AME) is a syndrome attributable to congenital deficiency of the enzyme 11 beta-dehydrogenase (11 beta-OHSD) which converts active glucocorticoid cortisol to inactive cortisone. When 11 beta-OHSD activity is impaired, cortisol acts as a potent mineralocorticoid and causes hypertension and hypokalemia with a suppression of the renin-angiotensin-aldosterone system. The increased ratio of urinary cortisol/cortisone metabolites and a prolonged half-life of cortisol are useful for the diagnosis. Dexamethasone and/or potassium sparing diuretics have been used for medication of AME. Licorice ingestion induces a mineralocorticoid excess state, and it seems that this is the result of acquired inhibition of 11 beta-DH by glycyrrhetinic acid. The existence of a second 11 beta-OHSD isoform has been suggested strongly for a long time, and recently, a human 11 beta-OHSD 2 cDNA has been isolated. It appears that 11 beta-OHSD 2 conveys specificity upon the renal MR, and a defect in its activity seems likely to account for the phenotype of AME.

11 beta-Hydroxysteroid dehydrogenase and its inhibitors in hypertensive pregnancy

Preeclampsia is accompanied by amplification of the sodium retention that is a feature of normal pregnancy. Recent evidence suggests that mineralocorticoid receptor activation is increased in preeclampsia, but classic mineralocorticoids (aldosterone, 11-deoxycorticosterone) are not present in excess. Cortisol can act as a mineralocorticoid receptor agonist only when its renal inactivation to cortisone by 11 beta-hydroxy-steroid dehydrogenase is impaired, for example, in congenital enzyme deficiency and after administration of exogenous inhibitors (eg, licorice). Endogenous inhibitors of this enzyme have been detected in human urine and are increased in pregnancy. To establish whether cortisol causes mineralocorticoid excess in hypertensive pregnancy and whether endogenous inhibitors of 11 beta-hydroxysteroid dehydrogenase are responsible, we studied 25 hypertensive pregnant patients (13 with preeclampsia and 12 with gestational hypertension), 16 normotensive pregnant subjects, and 13 nonpregnant control subjects. Concentrations of plasma renin and aldosterone were increased in pregnancy, but less so in hypertensive pregnancy. Plasma potassium and urinary electrolytes were not different between the groups. Plasma cortisol was increased in pregnancy but not different in hypertensive pregnancy, and urinary cortisol, plasma and urinary cortisone, and urinary tetrahydrocortisol and tetrahydrocortisone were not different between the groups. Endogenous inhibitors of 11 beta-hydroxysteroid dehydrogenase were more active in urine from pregnant women but were not increased further in hypertensive pregnancy. There were no differences in these parameters between patients with preeclampsia and gestational hypertension. We conclude that deficient inactivation of cortisol to cortisone does not contribute to the sodium retention of normotensive or hypertensive pregnancy and that endogenous inhibitors of 11 beta-hydroxysteroid dehydrogenase have no evident pathophysiological significance in pregnancy.

Mass spectrometry in the diagnosis of steroid-related disorders and in hypertension research

The use of GC/MS and microbore HPLC/electrospray mass spectrometry for clinical studies in hypertension and mineralocorticoid research is described. In particular, an automated GC/MS method allows nearly quantitative measurements of metabolites of major steroids of adrenal, placental and gonadal origin. This method is able to distinguish almost all steroid related disorders. Electrospray mass spectrometry in conjunction with microbore HPLC is the latest mass spectrometry technique applicable to biochemical investigations. It offers high sensitivity (15 pg) for measurement of intact steroid conjugates and related compounds.

A neonate with idiopathic hyperaldosteronism

A boy with functional abnormalities of the gastro-intestinal tract, hyponatraemia, hypokalaemia and hypertension is described. All symptoms developed within the first 2 months of life. Increased aldosterone levels were associated with suppressed values in the renin-angiotensin system. The diagnosis of idiopathic hyperaldosteronism was made because of adrenal hyperplasia and the failure to suppress aldosterone to undetectable levels with glucocorticoids. Treatment with spironolactone alone, or in combination with either intravenous dopamine or ibopamine orally, amiloride, enalapril, hydralazine or clonidine corrected serum potassium values but failed to normalize blood pressure and to correct plasma renin activity and plasma aldosterone. However, the combination of spironolactone with nifedipine decreased blood pressure. Abnormal gastro-intestinal motility was corrected by low doses of oral magnesium hydroxide. To assess intracellular calcium homeostasis, the patient's peripheral blood mononuclear cells were incubated with increasing concentrations of calcium. As these cells failed to maintain physiological calcium concentration, a defect in intracellular calcium homeostasis was suspected.

The cortisol-cortisone shuttle and hypertension

11 beta-OHSD is an enzyme complex consisting of 11 beta-DH, converting cortisol to cortisone in man and an 11-keto-reductase performing the reverse reaction. Congenital deficiency of 11 beta-DH should be considered in any child presenting with mineralocorticoid hypertension and suppression of the renin-angiotensin-aldosterone axis. The keystone to diagnosis is the demonstration of a reduced daily production rate of cortisol and an increase in its plasma half-life. In the majority of cases diagnosis can be made from a urinary steroid metabolite profile indicating a high excretion of cortisol relative to cortisone metabolites. Cortisol is the responsible mineralocorticoid, and as such treatment with the pure glucocorticoid dexamethasone will prevent life-threatening hypokalemia, although additional anti-hypertensive drugs are usually required to control blood pressure. Liquorice and carbenoxolone, for years thought to be direct "agonists" of the mineralocorticoid receptor, in fact cause sodium retention through inhibition of 11 beta-DH. The demonstration of 11 beta-DH activity in the vasculature raises the possibility that it locally modules access of glucocorticoids to mineralocorticoid and possibly glucocorticoid receptors in the vessel wall. It remains possible that subtle alterations of this cortisol-cortisone shuttle are responsible for other forms of hypertension which are currently classified under the umbrella diagnosis of essential hypertension.

Evidence of formation of isomeric methoximes from 20-oxosteroids

The formation and gas chromatographic behavior of syn- and anti-isomers in position 20 of the methoxime-trimethylsilyl (MO-TMS) derivatives of many 20-oxo and 3,20-dioxo-21-hydroxysteroids is reported. The existence of such isomers was established from the gas chromatographic (GC) and mass spectrometric analysis of the MO-TMS derivatives of 3 alpha,21-dihydroxy-5 beta-pregnan-20-one and its 17 alpha-epimer. The degree of separation during GC analysis of the syn- and anti-isomers in position 20, as well as those in position 3, is associated to the position of additional hydroxyl groups on the steroid ring. These data are very important for the location of oxygenated substituents such as 2 alpha/2 beta, 6 alpha/6 beta, 11 beta, 16 alpha, 17 alpha, 18, 19 or 21-hydroxyl groups during structural studies of 20-oxo and 3,20-dioxosteroids.

Isoelectric focusing analysis of detergent extracted renal 11 beta-hydroxysteroid dehydrogenase

11 beta-hydroxysteroid dehydrogenase (11-HSD, EC 1.1.1.146) from rat renal cortex microsomes was solubilized using several detergents, the most effective being Zwittergent 3-10 and Triton X-100. The activity ratio oxidation/reduction of the reversible reaction corticosterone in equilibrium 11-dehydrocoticosterone varied depending on the detergent used. We attribute this variation to direct effects of different detergents on enzyme kinetics. In contrast, comparable results obtained with liver 11-HSD have been attributed to the possibility of spatially separated 11-oxidase and 11-reductase activities. In order to test whether renal 11-HSD represents a uniform oxido-reductase as generally assumed, or a dual enzyme system as has been recently proposed an attempt was made to characterize 11-HSD solubilized from renal microsomal fractions using isoelectric focusing (IEF). When 11-HSD was extracted with 1% Triton X-100 (= partially solubilized fraction) a heterogenous peak pattern was obtained. In contrast, IEF of 11-HSD extracted with 10% Triton X-100 (= delipidated fraction) resulted in a single peak at about pH 5.9 with both oxidative and reductive activity at practically identical positions within the gels. From this observation we conclude that the degree of detergent solubilization of a membrane bound protein affects its amphoteric properties and that removal of membranous lipids is a prerequisite for the analysis of its behaviour. Since the more delipidated fraction of 11-HSD revealed only one activity peak the data are compatible with the uniform enzyme concept since oxidative and reductive activities of renal cortical 11-HSD could not be separated.

A new form of the syndrome of apparent mineralocorticoid excess

The syndrome of apparent mineralocorticoid excess combines the features of unexplained but spironolactone-correctable mineralocorticoid excess in association with a decreased rate of oxidation of cortisol to cortisone. No relationship was initially implied between the pathogenesis of the disorder and the metabolic disturbance as expressed by an elevated cortisol:cortisone metabolite ratio but the ratio itself has served as a biochemical marker for the disorder. Cortisol has been suggested as the mineralocorticoid in a setting of enhanced sensitivity to the steroid as a result of the incomplete oxidative metabolism of cortisol by the kidney. We present evidence that diminished conversion of cortisol to cortisone is not an obligatory mechanism in the syndrome of apparent mineralocorticoid excess. A form of the disorder is described, designated the Type 2 variant, in which all features are preserved except that the cortisol:cortisone metabolite ratio is normal. An essential feature of both variants, however, is a decrease in the cortisol metabolic clearance rate. These findings require a more generalized definition of the syndrome of apparent mineralocorticoid excess to include other deficient mechanisms of metabolic inactivation of cortisol.

Syndrome of apparent mineralocorticoid excess. A defect in the cortisol-cortisone shuttle

The first adult case of 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) deficiency is described. The impaired conversion of cortisol to cortisone (indicated by urinary cortisol and cortisone metabolites and failure to metabolize 11 alpha-[3H]cortisol to [3H]H2O), was associated with hypertension, hypokalemia, and suppression of the renin-angiotensin-aldosterone system. When established on a fixed Na+/K+ intake, dexamethasone, given orally, produced a natriuresis and potassium retention. Plasma renin activity became detectable. When hydrocortisone (10 mg daily s.c. for 4 d) was added, there was marked Na+ retention, a kaliuresis (urinary Na+/K+ falling from 1.2 to 0.15), with suppression of plasma renin activity and an increase in blood pressure. These changes were also seen with the subject on no treatment. Conversion of cortisone to cortisol was not affected. These results suggest that cortisol acts as a potent mineralocorticoid in 11 beta-OHSD deficiency. The major site for the oxidation of cortisol to cortisone is the kidney. In this patient congenital deficiency of 11 beta-OHSD results in high intrarenal cortisol levels which then act on renal type I mineralocorticoid receptors. This condition can be treated with dexamethasone, which suppresses cortisol secretion and binds to the type II glucocorticoid receptor. We suggest that 11 beta-OHSD exerts a critical paracrine role in determining the specificity of the type I receptor. In the normal state cortisol is converted by 11 beta-OHSD to cortisone which thus allows aldosterone to bind preferentially to the type I receptors in the kidney and gut. In this patient deficiency of 11 beta-OHSD results in high intrarenal cortisol concentrations that then bind to the type I receptor.

New findings in apparent mineralocorticoid excess

We report two female siblings (ages 4 and 9 years) and one 8-year-old male with the syndrome of apparent mineralocorticoid excess (AME) presenting with low renin hypertension and hypoaldosteronism. The deficiency of 11 beta-hydroxysteroid dehydrogenase results in a defect of the peripheral metabolism of cortisol (F) to cortisone (E). As a result, the serum cortisol half-life (T1/2) is prolonged, ACTH is suppressed, and serum F is normal. The specific diagnosis of the disorder was made by the decreased ratio of the urinary metabolites of E (tetrahydrocortisone, THE) and F (tetrahydrocortisol, THF). Continuous i.v. hydrocortisone administration caused an increase in blood pressure and decrease in serum potassium demonstrating the abnormal mineralocorticoid activity of cortisol in these patients. Addition of spironolactone resulted in a decrease in blood pressure, rise in serum potassium and a gradual increase in plasma renin activity. These studies suggest that an abnormality in cortisol action or metabolism results in cortisol behaving as a potent mineralocorticoid and causing the syndrome of AME.

Spironolactone-reversible rickets associated with 11 beta-hydroxysteroid dehydrogenase deficiency syndrome

A 7-year-old girl had growth retardation, hypertension, and hypokalemic alkalosis. Baseline serum aldosterone concentration and plasma renin activity were low and unresponsive to sodium deprivation and to orthostatic changes. Baseline serum progesterone, 17-hydroxyprogesterone, 11-deoxycortisol, and cortisol levels were normal and adequately responsive to ACTH stimulation. No steroid was found abnormally elevated. A diagnosis of 11 beta-hydroxysteroid dehydrogenase deficiency was established on the basis of elevated urinary tetrahydrocortisol plus allotetrahydrocortisol/tetrahydrocortisone ratio, determined by gas chromatography-mass spectrometry. Evaluation of bone mineral metabolism and parathyroid function, and skeletal radiographs, revealed the presence of rickets and secondary hyperparathyroidism. Treatment with spironolactone alone for 2 months corrected hypertension, hypokalemic alkalosis, and all laboratory and radiologic evidence of rickets and hyperparathyroidism, resulting in acceleration of growth rate. The response to spironolactone suggests that a hypermineralocorticoid state is responsible for the hypertensive syndrome and that rickets and hyperparathyroidism could be a consequence of excess mineralocorticoid activity.

Profiling steroid hormones and urinary steroids

This paper reviews techniques utilized in the profiling of steroids in body fluids and tissues. Methods for profiling plasma unconjugated steroids and urinary steroid metabolites are focused on. Concentrations or levels of excretion of a variety of steroids have been documented and reviewed. The importance of profiling techniques in the study of normal and pathophysiology of hormonal steroids is discussed.

Apparent mineralocorticoid excess causing hypertension and hypokalemia in children

Cortisol 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) deficiency was observed in four patients with apparent mineralocorticoid excess. The 11 beta-HSD deficiency was demonstrated by a markedly decreased urinary tetrahydrocortisone/tetrahydrocortisol (THE/THF) ratio (less than 1 in normal children) during infusion of ACTH and administration of hydrocortisone. We propose that in these patients the 11 beta-HSD deficiency impairs the metabolism of cortisol to cortisone, resulting in a prolonged cortisol half-life, suppression of ACTH, and normal serum cortisol. The 11 beta-HSD deficiency protects the patient from adrenal insufficiency despite the low cortisol secretion; the prolonged half-life of cortisol may contribute to the hypertension and hyporeninemia observed in this disorder. Continuous intravenous hydrocortisone administration resulted in increased blood pressure and decreased serum potassium. Addition of spironolactone during continued administration of 20 mg per day of hydrocortisone resulted in a decrease in blood pressure and a rise in serum potassium. These studies suggest that an abnormality in cortisol action or metabolism results in cortisol behaving as a potent mineralocorticoid. These findings may account for this syndrome of apparent mineralocorticoid excess.

Steroid profiles in urine and plasma of alcoholics during withdrawal

Metabolic profiles of steroids in urine and plasma were analyzed in 14 male and four female alcoholics during withdrawal. The daily excretion of 30 conjugated steroids in urine and the concentration of 13 steroid sulfates in plasma were measured on days 1, 7 and 29 of the period of observation, which started on day 5-7 of abstinence. While the total excretion of cortisol metabolites was normal in most cases, the profiles of metabolites were changed in the alcoholics during the period of observation. The ratio between tetrahydrocortisol and tetrahydrocortisone exceeded the mean normal value by more than one standard deviation in 97% of the samples analyzed. The same was true of the ratio between 20-hydroxy and 20-oxosteroids in 90% of the samples. The differences between alcoholic and healthy subjects were statistically significant (p less than 0.001). The major change in plasma was a significantly increased concentration of 5-androstene-3 beta, 17 beta-diol disulfate on the first day of the study. The concentration decreased to normal values during the first month of withdrawal. The rate of excretion of this steroid in urine was increased in half of the patients and also decreased with time. The rate of excretion and the degree of fatty infiltration in liver biopsies were positively correlated. It is suggested that the ratios between cortisol metabolites in urine might be of value as biochemical markers in alcoholism, and that the absolute or relative concentrations of steroid disulfates in plasma might serve as an indicator of recent alcohol intake.

Congenital 11 beta-hydroxysteroid dehydrogenase deficiency associated with juvenile hypertension: corticosteroid metabolite profiles of four patients and their families

Four children with 11 beta-hydroxysteroid dehydrogenase deficiency are described. All patients had severe hypertension, hypokalaemia, and low plasma aldosterone and renin activities. Two of the patients were siblings and two were unrelated. The most noticeable biochemical feature of these individuals was the extremely low excretion of cortisol metabolites containing an 11-carbonyl group compared to the excretion of the 11 beta-hydroxyl containing metabolites. Although this condition is readily diagnosed in affected individuals by urinary steroid analysis, carriers of the defect do not differ from normal in their urinary steroids. Both parents of the affected siblings had normal 11-oxo-steroid/11 beta-hydroxysteroid ratios under baseline conditions and the lesions could not be revealed by ACTH administration.

Extraction of 11 beta-hydroxysteroid dehydrogenase from rat liver microsomes by detergents

In these studies our goal was to solubilize the microsomal enzyme, 11 beta-hydroxysteroid dehydrogenase (11-HSD) as the first step in its purification. Enzyme was extracted from rat liver microsomes with representative detergents (Zwittergents, Tritons, modified sterols). Oxidation-reduction (O-R) ratios of extracts varied with detergent used and ranged from 0.18 (CHAPS) to 3.8 (Zwittergent 3-14) relative to a ratio of 1.7 in intact microsomes. All detergents solubilized 11-HSD using lack of sedimentation during high speed centrifugation as criterion. With Triton DF-18 and Triton X-100, optimum extraction of 11-HSD occurred in the detergent-protein ratio range of 0.1 to 0.2 O-R ratios decreased with increased Triton X-100, but were constant as Triton DF-18 was varied. The pH optimum of enzyme extraction was 9 at a detergent-protein ratio of 0.05 and 7.5-8.0 at a ratio of 0.2. Sodium chloride increased enzyme extraction by detergents; in the absence of detergent, salt extracted protein, but not enzyme. In aqueous solution at 0 degrees C or -15 degrees C, microsomal 11-oxidation activity rose within 24 h, then decreased; reductase activity consistently decreased. Oxidation and reduction activities were inversely related in the microsomal bound enzyme. No relationship between these activities appeared in detergent-solubilized enzymes. Possible mechanisms to account for the unexpected behavior of this enzyme are discussed.

11 beta-Hydroxysteroid dehydrogenase: fact or fancy?

Previous attempts to explain the diverse behavior of 11 beta-hydroxysteroid dehydrogenase (11-HSD) within and between species have not been successful. We now propose that 11-HSD activity is the resultant of the coordinated interaction of two enzyme types, 11-dehydrogenase and 11-reductase. We have demonstrated their separate existence by physico-chemical and kinetic methods. Based on these findings, two classes of disease in humans that have been recently described can now be characterized as being associated with a deficiency in either 11-dehydrogenase or 11-reductase.

Apparent mineralocorticoid excess and deficient 11 beta-oxidation of cortisol in a young female

A 19-year-old female, known to have had hypertension and hypokalemic alkalosis since the age of 9 months, was found to have suppressed renin, negligible plasma and urinary aldosterone and low plasma levels of other known sodium-retaining steroids. Despite the normal plasma cortisol the urinary excretion of 17-oxosteroids and 17-oxogenic steroids was low as was the cortisol secretion rate, suggesting a diminished metabolic clearance of cortisol. This was confirmed by the demonstration of a prolonged t 1/2 of 14C-cortisol. The abnormally high urinary excretion ratios of cortisol to cortisone, tetrahydracortisol to tetrahydrocortisone and 11-hydroxy-aetiocholanolone to 11-oxy-aetiocholanolone indicate that the diminished cortisol breakdown is the result of deficient 11 beta-oxidation. Moreover, the urinary excretion of free cortisol was elevated, probably due to diminished tubular reabsorption of cortisol. Hypokalemic alkalosis did not respond to spironolactone, but was partly corrected by amiloride. No response to dexamethasone was observed, but dexamethasone combined with aminogluthetimide normalized blood pressure and serum K. These findings support the involvement of a sodium-retaining, kaliuretic steroid in this rare syndrome.

Fatal, low renin hypertension associated with a disturbance of cortisol metabolism

A 5 month old boy died after fever, persistently raised blood pressure, and hypokalaemia. A disorder of cortisol metabolism caused by 11 beta-hydroxysteroid dehydrogenase deficiency was detected retrospectively.

Partial characterization of unusual polar steroids in the urine of a child with low renin hypertension

Analysis of urinary steroids excreted by a 7-year old girl with low renin hypertension following ACTH treatment revealed several unknown steroids, which have been analysed by gas chromatography-mass spectrometry. It is proposed that these steroids are monohydroxylated derivatives of cortisol, cortisone, either or both tetrahydro and allo-tetrahydrocortisol and either or both tetrahydro and allo-tetrahydro-11-deoxycortisol. Further analysis indicated that there are two likely positions for the additional hydroxyl group, either on the A or B ring.