Consideraciones en el manejo del adulto con Hiperplasia Suprarrenal congénita clásica por déficit de 21-Hidroxilasa / Management considerations for the adult with congenital adrenal hyperplasia due 21-hydroxylase deficiency

La Hiperplasia Suprarrenal Congénita (HSRC) corresponde a un grupo de defectos genéticos en la síntesis de cortisol. El 95% de ellas son debidas al déficit de 21-hidroxilasa por lo que nos referiremos solo a esta deficiencia. La hiperplasia suprarrenal congénita clásica (HSRC-C) debuta en recién nacidos o lactantes con insuficiencia suprarrenal primaria, diferentes grados de hiperandrogenismo clínico en mujeres y puede coexistir con hipotensión, hiperkalemia e hiponatremia si hay un déficit clínico de aldosterona. El objetivo de este artículo es actualizar el conocimiento y enfoques sugeridos para el manejo de la HSRC-C desde el inicio de sus controles en la etapa adulta. El diagnóstico diferencial en retrospectiva de la HSRC-C y la no clásica (HSRC-NC) a veces resulta difícil ya que esta enfermedad es un espectro fenotípico continuo. La insuficiencia suprarrenal y la dependencia a terapia corticoidal son los eventos principales para diferenciar estas dos patologías que tienen enfoques terapéuticos diferentes. El tratamiento de la HSRC-C en adultos abarca 2 objetivos primarios: la adecuada sustitución de la falla suprarrenal y el control de hiperandrogenismo mediante el uso de corticoides en sus dosis mínimas efectivas. En la mujer existen terapias complementarias para el control del hiperandrogenismo como anticonceptivos y otras que se encuentran en diferentes fases de investigación. Esto permite disminuir las dosis de corticoides en algunos casos. Es importante a la vez abordar tres objetivos secundarios: controlar el riesgo cardiometabólico propio de la enfermedad, evitar el sobre tratamiento corticoidal y manejar la infertilidad. La correcta monitorización del tratamiento en adultos tomando en cuenta los objetivos descritos permite una mejor calidad de vida en estos pacientes. Finalmente el consejo genético debe realizarse en todos los pacientes con HSRC que deseen fertilidad y en sus parejas. El estudio requiere de secuenciación del gen CYP21A2 y debe realizarse en un laboratorio de experiencia.

Congenital Adrenal Hyperplasia (CAH) are a group of genetic defects characterized by impaired cortisol synthesis. 95% of them are due to 21-hydroxylase deficiency. We will discuss only this enzyme's deficiency. Classic congenital adrenal hyperplasia (CAH-C) debuts in newborns or infants with primary adrenal insufficiency, some degree of clinical hyperandrogenism in newborn females, and can coexist with hypotension, hyperkalemia, and hyponatremia if there is a clinical aldosterone deficiency. The objective of this article is to update the knowledge and suggested approaches for the management of CAH-C from the beginning of its controls in the adult stage. The retrospective differential diagnosis of CAH-C and non-classical (CAH-NC) is sometimes difficult because this disease is a continuous phenotypic spectrum. Adrenal insufficiency and dependence on corticosteroid therapy are the main events to differentiate these two pathologies that have different therapeutic approaches. In adults, the treatment of CAH-C must include 2 primary objectives: adequate the replacement of adrenal failure and control of hyperandrogenism, through the use of corticosteroids in their minimum effective doses. In women there are complementary therapies for the control of hyperandrogenism, such as contraceptives and others that are in different phases of research. This makes it possible to reduce the doses of corticosteroids in some cases. It is important at the same time to address three secondary objectives: control the cardiometabolic risk of the disease secondary to corticosteroid treatment, avoid corticosteroid overtreatment and manage infertility. The correct monitoring of treatment in adults and taking in to account the objectives described, allows a better quality of life in these patients. Finally, genetic counseling must be carried out in all patients planning for children, with any type of CAH and in their partners. The study requires sequencing of the CYP21A2 gene and must be performed in a certified laboratory.

Endogenous insertion of non-native metalloporphyrins into human membrane cytochrome P450 enzymes.

Human cytochrome P450 enzymes are membrane-bound heme-containing monooxygenases. As is the case for many heme-containing enzymes, substitution of the metal in the center of the heme can be useful for mechanistic and structural studies of P450 enzymes. For many heme proteins, the iron protoporphyrin prosthetic group can be extracted and replaced with protoporphyrin containing another metal, but human membrane P450 enzymes are not stable enough for this approach. The method reported herein was developed to endogenously produce human membrane P450 proteins with a nonnative metal in the heme. This approach involved coexpression of the P450 of interest, a heme uptake system, and a chaperone in Escherichia coli growing in iron-depleted minimal medium supplemented with the desired trans-metallated protoporphyrin. Using the steroidogenic P450 enzymes CYP17A1 and CYP21A2 and the drug-metabolizing CYP3A4, we demonstrate that this approach can be used with several human P450 enzymes and several different metals, resulting in fully folded proteins appropriate for mechanistic, functional, and structural studies including solution NMR.

Extra-adrenal induction of Cyp21a1 ameliorates systemic steroid metabolism in a mouse model of congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase (21-OH) deficiency (21-OHD) is an autosomal recessive disorder, in which CYP21A2 mutations or deletions result in underproduction of glucocorticoid and mineralocorticoid, and overproduction of androgens. Patients with CAH are treated with oral steroid supplementation, but optimal control of blood steroid levels remains difficult. Thus, new therapeutic approaches are still needed. Previously, adenovirus-mediated administration of human CYP21A2 to adrenal glands rescued the phenotype of a mouse model of 21-OHD. In this study, we examined whether transduction of murine Cyp21a1 in extra-adrenal tissues could rescue steroid metabolism in 21-OHD mice. We transduced primary fibroblasts obtained from 21-OHD mice with a retroviral vector containing Cyp21a1. In vitro assays demonstrated that Cyp21a1-expressing fibroblasts can uptake progesterone from the culture media, convert it to deoxycorticosterone (DOC), and subsequently release DOC back into the media. Autotransplantation of Cyp21a1-expressing fibroblasts into the subcutaneous tissues of the back resulted in a significant reduction in the serum progesterone/DOC ratio in four of six 21-OHD mice at 4 weeks after injection. We also directly injected an adeno-associated viral vector containing Cyp21a1 into the thigh muscles of 21-OHD mice. Serum progesterone/DOC ratios were markedly reduced in all four animals at 4 weeks after injection. These results indicate that extra-adrenal induction of Cyp21a1 ameliorates steroid metabolism in 21-OHD mice. This study suggests a novel therapeutic strategy for congenital adrenal hyperplasia, which warrants further investigations.

Suppressed Sex Hormone Biosynthesis by Alkylresorcinols: A Possible Link to Chemoprevention.

Alkylresorcinols (ARs, 5-n-alkylresorcinols) are amphiphilic phenolic lipids in whole grain rye and wheat, with a long odd-numbered carbon chain. A preventive effect of whole grain diet on sex hormone-dependent cancers has been recognized, but the active component(s) or mechanisms are not known. We have investigated the effects of the ARs C15:0, C19:0, and C21:0, individually and in combination, on steroid hormone production by using the human adrenocortical cell line H295R. Decreased synthesis of dehydroepiandrosterone (DHEA), testosterone, and estradiol was demonstrated at low concentrations of C15:0 and C19:0. There were no indications of additive effects on steroid secretion from the combined treatment with equimolar concentrations of the three ARs. Gene expressions of CYP21A2, HSD3B2, and CYP19A1 were downregulated and CYP11A1 was upregulated by the ARs. The results on gene expression could not explain the effects on steroidogenesis, which may be due to direct effects on enzyme activities, such as inhibition of CYP17A1. Our results demonstrate suppressed synthesis of testosterone and estradiol by ARs suggesting a novel mechanism for ARs in the chemoprevention of prostate and breast cancer.

Comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats and microarray analysis of drug-metabolizing genes.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhein is a pharmacological active component found in Rheum palmatum L. that is the major herb of the San-Huang-Xie-Xin-Tang (SHXXT), a medicinal herbal product used as a remedy for constipation. Here we have investigated the comparative pharmacokinetics of rhein in normal and constipated rats. Microarray analysis was used to explore whether drug-metabolizing genes will be altered after SHXXT treatment. MATERIALS AND METHODS: The comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats was studied by liquid chromatography with electrospray ionization tandem mass spectrometry (LC-MS/MS). Gene expression profiling in drug-metabolizing genes after SHXXT treatment was investigated by microarray analysis and real-time polymerase chain reaction (RT-PCR). RESULTS: A validated LC-MS/MS method was applied to investigate the comparative pharmacokinetics of rhein in normal and loperamide-induced constipated rats. The pharmacokinetic results demonstrate that the loperamide-induced constipation reduced the absorption of rhein. Cmax significantly reduced by 2.5-fold, the AUC decreased by 27.8%; however, the elimination half-life (t1/2) was prolonged by 1.6-fold. Tmax and mean residence time (MRT) were significantly prolonged by 2.8-fold, and 1.7-fold, respectively. The volume of distribution (Vss) increased by 2.2-fold. The data of microarray analysis on gene expression indicate that five drug-metabolizing genes, including Cyp7a1, Cyp2c6, Ces2e, Atp1b1, and Slc7a2 were significantly altered by the SHXXT (0.5 g/kg) treatment. CONCLUSION: The loperamide-induced constipation reduced the absorption of rhein. Since among the 25,338 genes analyzed, there were five genes significantly altered by SHXXT treatment. Thus, information on minor drug-metabolizing genes altered by SHXXT treatment indicates that SHXXT is relatively safe for clinical application.

Genistein and daidzein affect in vitro steroidogenesis but not gene expression of steroidogenic enzymes in adrenals of pigs.

Phytoestrogens (PEs), including genistein and daidzein, are plant-derived substances that mimic or antagonize estrogen action in animals. The majority of studies investigated the effects of PEs on reproduction in humans and laboratory animals. The mechanisms of phytoestrogen action on reproductive processes in domesticated animals, including pigs, are garnering increasing attention. However, very few in vivo and in vitro studies investigating the effects of PEs on adrenal glands have been carried out on models other than humans and rats. The aim of the present study was to determine whether the effects of genistein and daidzein on adrenal in vitro steroidogenesis are accompanied by changes in expression of genes encoding key steroidogenic enzymes in porcine adrenocortical cells. The following genes were analyzed: cholesterol side-chain cleavage enzyme (P450scc, CYP11A1 gene), 3ß-hydroxysteroid dehydrogenase (3ß-HSD, HSD3B1 gene), 17α-hydroxylase/C17-20 lyase (P450c17, CYP17A1 gene) and 21-hydroxylase (P450c21, CYP21A2 gene). Porcine adrenocortical cells collected from both luteal- and follicular-phase gilts were exposed for eight hours to genistein (10 µM), or daidzein (10 µM), in the absence or presence of ACTH (5 nM). Genistein and daidzein inhibited basal and ACTH-stimulated secretion of cortisol and corticosterone and stimulated secretion of androstenedione. PEs did not affect the expression of CYP11A1, HSD3B1, CYP17A1 and CYP21A2 in the adrenocortical cells of luteal- and follicular-phase gilts. It can be concluded that the influence of PEs on steroid secretion in porcine adrenal glands is not mediated by changes in the expression of genes encoding major steroidogenic enzymes. More studies are needed to elucidate the intracellular mechanisms leading to the PE-induced changes in adrenal steroidogenesis in pigs.

Diagnosis and management of classical congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) is among the most common genetic disorders. Deficiency of adrenal steroid 21-hydroxylase deficiency due to mutations in the CYP21A2 gene accounts for about 95% cases of CAH. This disorder manifests with androgen excess with or without salt wasting. It also is a potentially life threatening disorder; neonatal screening with 17-hydroxyprogesterone measurement can diagnose the condition in asymptomatic children. Carefully monitored therapy with glucocorticoid and mineralocorticoid supplementation will ensure optimal growth and development for children with CAH. Genital surgery may be required for girls with CAH. Continued care is required for individuals with CAH as adults to prevent long-term adverse consequences of the disease, including infertility, metabolic syndrome and osteoporosis.

Cytochrome P450 dysregulations in thioacetamide-induced liver cirrhosis in rats and the counteracting effects of hepatoprotective agents.

Dysregulations of cytochromes P450 (P450s) under liver injury have been extensively studied. However, little is known about the possible reversing effects of hepatoprotective agents, the understanding of which is of great importance in guiding clinical dosage adjustment for patients with liver injury. This study aims to investigate the dysregulation patterns of major P450s in thioacetamide (TAA)-induced liver cirrhosis in rats and the potential counteracting effects of hepatoprotective agents schisandra lignans extract (SLE) and dimethyl diphenyl bicarboxylate (DDB). TAA intoxications for 6 weeks induced apparent liver injury and dramatically reduced the hepatic protein expressions of CYP1A2, CYP2C6, CYP2E1, and CYP3A2 to 18, 71, 30, and 21% of that in the normal control, respectively. Both SLE and DDB treatments could significantly reverse the TAA-induced loss of P450 protein levels, which may be ascribed to their hepatoprotective effects and direct P450-inducing effects that have been confirmed in healthy rats. However, the recovery of enzyme activities of most P450s by SLE and DDB treatment was less evident than that for the protein expression levels. TAA exhibited NADPH-, time-, and concentration-dependent inactivating effects on all of the four major P450 isozymes; both DDB and GSH showed little effects on counteracting such an inactivation efficacy. These findings provided a good explanation on the disproportional effects of hepatoprotective agents in recovering the protein levels and enzyme activities of TAA-induced dysregulated P450s.

Molecular testing in congenital adrenal hyperplasia due to 21α-hydroxylase deficiency in the era of newborn screening.

Newborn screening (NBS) identifies the majority of classical [salt-wasting (SW) and simple-virilizing (SV)] cases of congenital adrenal hyperplasia (CAH) due to 21α-hydroxylase (21α-OHase) during the first days of life. Diagnosis of classical CAH is confirmed by follow-up serum 17-hydroxyprogesterone and/or the adrenocorticotropin stimulation test; however, neither test definitively distinguishes between the classical subtypes. After confirmation, all newborns are started on hydrocortisone (glucocorticoid) and fludrocortisone (mineralocorticoid) treatment. While initiating fludrocortisone treatment in classical CAH patients, independent of subtype and before SW signs or symptoms occur, prevents a life-threatening SW crisis, it may later complicate distinguishing between the classical subtypes. Genotype-phenotype correlations in 21α-OHase deficiency are excellent; however, molecular testing is not a regular part of the diagnostic workup. Molecular testing on 39 patients (25 identified by NBS) with an already established diagnosis of CAH identified 11 SW patients (8 identified by NBS) whose mutations suggested further biochemical and clinical reassessment of their subtype. Overall, SW accounted for 57.6% of our classical CAH patients, below the generally accepted figure that >75% of classical CAH are comprised of the SW form. In the era of NBS, molecular testing is a valuable supplemental tool identifying patients who may benefit from reassessment of their salt-retaining ability.

The influence of Aspalathus linearis (Rooibos) and dihydrochalcones on adrenal steroidogenesis: quantification of steroid intermediates and end products in H295R cells.

The steroid hormone output of the adrenal gland is crucial in the maintenance of hormonal homeostasis, with hormonal imbalances being associated with numerous clinical conditions which include, amongst others, hypertension, metabolic syndrome, cardiovascular disease, insulin resistance and type 2 diabetes. Aspalathus linearis (Rooibos), which has been reported to aid stress-related symptoms linked to metabolic diseases, contains a wide spectrum of bioactive phenolic compounds of which aspalathin is unique. In this study the inhibitory effects of Rooibos and the dihydrochalcones, aspalathin and nothofagin, were investigated on adrenal steroidogenesis. The activities of both cytochrome P450 17α-hydroxylase/17,20 lyase and cytochrome P450 21-hydroxylase were significantly inhibited in COS-1 cells. In order to study the effect of these compounds in H295R cells, a human adrenal carcinoma cell line, a novel UPLC-MS/MS method was developed for the detection and quantification of twenty-one steroid metabolites using a single chromatographic separation. Under both basal and forskolin-stimulated conditions, the total amount of steroids produced in H295R cells significantly decreased in the presence of Rooibos, aspalathin and nothofagin. Under stimulated conditions, Rooibos decreased the total steroid output 4-fold and resulted in a significant reduction of aldosterone and cortisol precursors. Dehydroepiandrosterone-sulfate levels were unchanged, while the levels of androstenedione (A4) and 11ß-hydroxyandrostenedione (11ßOH-A4) were inhibited 5.5 and 2.3-fold, respectively. Quantification of 11ßOH-A4 showed this metabolite to be a major product of steroidogenesis in H295R cells and we confirm, for the first time, that this steroid metabolite is the product of the hydroxylation of A4 by human cytochrome P450 11ß-hydroxylase. Taken together our results demonstrate that Rooibos, aspalathin and nothofagin influence steroid hormone biosynthesis and the flux through the mineralocorticoid, glucocorticoid and androgen pathways, thus possibly contributing to the alleviation of negative effects arising from elevated glucocorticoid levels.

[Effects of Schisandra chinensis (Wuweizi) constituents on the activity of hepatic microsomal CYP450 isozymes in rats detected by using a cocktail probe substrates method].

Effects of constituents from Schisandra chinensis (Wuweizi) on six liver microsomal CYP450 isozymes (CYP1A2, CYP2C6, CYP2C11, CYP2D2, CYP2E1 and CYP3A1/2) were studied in rats in vivo and in vitro. The in vitro incubation was conducted using liver microsomes of rats after multiple dosing of alcoholic/water extract from Schisandra chinensis. A HPLC-MS method was applied to determine the metabolites formation of six CYP450s probe substrates (phenacetin-CYP1A2, dextromethorphan-CYP2D2, diclofenac sodium-CYP2C6, mephenytoin-CYP2C11, chlorzoxazone-CYP2E1 and midazolam-CYP3A1/2) in rat liver microsomal incubations. The activity of CYP450 isozymes were represented by the formation of metabolites. Alcoholic extract of Schisandra chinensis (28-120 microg x mL(-1)) showed significant inhibitory effect on six CYP450 isozymes to a certain extent in vitro. Multiple dosing of Schisandra chinensis alcoholic extract (1.5 g x kg(-1), qd x 7d) had significant induction on CYP2E1 and CYP3A1/2, inhibition on CYP2D2 and CYP2C11, and no effect on CYP2C6 and CYP1A2. Water extract of Schisandra chinensis (100-500 microg x mL(-1)) also exhibited inhibition on the activity of CYP450 isozymes in vitro, whereas multiple administrations (1.5 g x kg(-1), qd x 7d) had significant induction of CYP2E1 and inhibition on CYP2D2, no effect on CYP2C6, CYP3A1/2, CYP1A2 or CYP2C11. The results suggested that the constituents from Schisandra chinensis exhibited the inhibition and induction on six rat liver microsomal CYP450 isozymes to a certain extent in vivo and in vitro. The possibility of interaction between Schisandra chinensis and coadministrative drugs will be considered base on the levels and subtype of CYP450 involved in the drug metabolism.

Effects of Schisandra chinensis (Wuweizi) constituents on the activity of hepatic microsomal CYP450 isozymes in rats detected by using a cocktail probe substrates method / 药学学报

Effects of constituents from Schisandra chinensis (Wuweizi) on six liver microsomal CYP450 isozymes (CYP1A2, CYP2C6, CYP2C11, CYP2D2, CYP2E1 and CYP3A1/2) were studied in rats in vivo and in vitro. The in vitro incubation was conducted using liver microsomes of rats after multiple dosing of alcoholic/water extract from Schisandra chinensis. A HPLC-MS method was applied to determine the metabolites formation of six CYP450s probe substrates (phenacetin-CYP1A2, dextromethorphan-CYP2D2, diclofenac sodium-CYP2C6, mephenytoin-CYP2C11, chlorzoxazone-CYP2E1 and midazolam-CYP3A1/2) in rat liver microsomal incubations. The activity of CYP450 isozymes were represented by the formation of metabolites. Alcoholic extract of Schisandra chinensis (28-120 microg x mL(-1)) showed significant inhibitory effect on six CYP450 isozymes to a certain extent in vitro. Multiple dosing of Schisandra chinensis alcoholic extract (1.5 g x kg(-1), qd x 7d) had significant induction on CYP2E1 and CYP3A1/2, inhibition on CYP2D2 and CYP2C11, and no effect on CYP2C6 and CYP1A2. Water extract of Schisandra chinensis (100-500 microg x mL(-1)) also exhibited inhibition on the activity of CYP450 isozymes in vitro, whereas multiple administrations (1.5 g x kg(-1), qd x 7d) had significant induction of CYP2E1 and inhibition on CYP2D2, no effect on CYP2C6, CYP3A1/2, CYP1A2 or CYP2C11. The results suggested that the constituents from Schisandra chinensis exhibited the inhibition and induction on six rat liver microsomal CYP450 isozymes to a certain extent in vivo and in vitro. The possibility of interaction between Schisandra chinensis and coadministrative drugs will be considered base on the levels and subtype of CYP450 involved in the drug metabolism.

Congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency: an Endocrine Society clinical practice guideline.

OBJECTIVE: We developed clinical practice guidelines for congenital adrenal hyperplasia (CAH). PARTICIPANTS: The Task Force included a chair, selected by The Endocrine Society Clinical Guidelines Subcommittee (CGS), ten additional clinicians experienced in treating CAH, a methodologist, and a medical writer. Additional experts were also consulted. The authors received no corporate funding or remuneration. CONSENSUS PROCESS: Consensus was guided by systematic reviews of evidence and discussions. The guidelines were reviewed and approved sequentially by The Endocrine Society's CGS and Clinical Affairs Core Committee, members responding to a web posting, and The Endocrine Society Council. At each stage, the Task Force incorporated changes in response to written comments. CONCLUSIONS: We recommend universal newborn screening for severe steroid 21-hydroxylase deficiency followed by confirmatory tests. We recommend that prenatal treatment of CAH continue to be regarded as experimental. The diagnosis rests on clinical and hormonal data; genotyping is reserved for equivocal cases and genetic counseling. Glucocorticoid dosage should be minimized to avoid iatrogenic Cushing's syndrome. Mineralocorticoids and, in infants, supplemental sodium are recommended in classic CAH patients. We recommend against the routine use of experimental therapies to promote growth and delay puberty; we suggest patients avoid adrenalectomy. Surgical guidelines emphasize early single-stage genital repair for severely virilized girls, performed by experienced surgeons. Clinicians should consider patients' quality of life, consulting mental health professionals as appropriate. At the transition to adulthood, we recommend monitoring for potential complications of CAH. Finally, we recommend judicious use of medication during pregnancy and in symptomatic patients with nonclassic CAH.

Prediction of metabolic clearance of diclofenac in adjuvant-induced arthritis rats using a substrate depletion assay.

1. The purpose of this study was to evaluate drug clearance measured by the metabolic intrinsic clearance (CL(int)) in a substrate depletion assay in comparison with the in vivo clearance (CL(tot)) observed in adjuvant-induced arthritis (AA) rats. 2. After intravenous administration of diclofenac as a model drug, CL(tot) was 2.8-fold higher in AA rats than in control rats. In two different substrate depletion assays with liver microsomes for glucuronidation and hydroxylation, the CL(int) values for glucuronidation was significantly decreased in AA rats to 60% of the value in control rats, whereas the CL(int) values for hydroxylation were similar. The unbound fraction of diclofenac in plasma (f(u, plasma)) was significantly higher (2.8-fold) in AA rats than in control rats. 3. Hepatic clearance predicted from the CL(int) values for both biotransformation pathways and f(u, plasma) was higher in AA rats than in control rats, with good consistency between predicted and observed values. The same results were obtained for experiments using hepatocytes. 4. The plasma protein-binding activities, rather than metabolic clearance, in both types of rats would be a determining factor in the pharmacokinetic behaviour differences between control and AA rats. 5. In summary, substrate depletion assays with liver microsomes and hepatocytes in combination with protein binding assessment can help to predict changes in pharmacokinetics under AA conditions.

Use of molecular simulation for mapping conformational CYP2E1 epitopes.

The identification of the epitopes recognized by autoantibodies against cytochrome P450s (CYPs) associated with drug-induced hepatotoxicity is difficult because of their conformational nature. In the present investigation, we used a novel approach based on the analysis of the whole molecule antigenic capacity following single amino acid substitutions to identify the conformational epitopes on CYP2E1. A molecular model of CYP2E1 was generated based on the CYP2C5 crystal structure, and potential motifs for amino acid exchanges were selected by computer simulation in the surface of alpha helices and beta sheets. Fourteen modified, apparently correctly folded CYP2E1 variants were produced in Escherichia coli and evaluated in immunoprecipitation experiments using sera with anti-CYP2E1 autoreactivity from 10 patients with halothane hepatitis and 12 patients with alcoholic liver disease. Ala substitution of Glu-248 and Lys-251 as well as of Lys-324, Lys-342, Lys-420, and Phe-421 severely decreased or abolished CYP2E1 recognition by the majority of both the halothane hepatitis and alcoholic liver disease sera, whereas the other substitutions had only minor effects. Based on the structural model, these substitutions identified two distinct epitopes on the CYP2E1 surface corresponding to the G-helix and an area formed by juxtaposition of the J' and K'' helices, respectively. The combined use of molecular modeling and single amino acid mutagenesis is thus a useful approach for the characterization of conformational epitopes recognized by autoantibodies.

The effect of Sutherlandia frutescens on steroidogenesis: confirming indigenous wisdom.

Sutherlandia frutescens (Cancer bush), a Southern African indigenous plant, is traditionally used to treat stress related maladies linked to the endocrine system. Extracts of the shrub were used to investigate the claimed stress-relieving properties of the shrub. Dysregulation of the stress response is associated with elevated glucocorticoid levels. A model of chronic intermittent immobilization stress was investigated in 40 adult male Wistar rats to determine the effect of Sutherlandia. Immobilization stress resulted in increased corticosterone levels in the control group while rats receiving Sutherlandia extract showed significantly decreased corticosterone levels (P < 0.005). Since the biosynthesis of glucocorticoids in the adrenals is catalyzed by the cytochrome P450-dependent enzymes, the influence of Sutherlandia extracts on adrenal steroidogenesis was determined in ovine adrenocortical microsomes and mitochondria, using spectral binding and enzyme conversion assays. Water extracts showed inhibition of substrate binding to cytochrome P450 21-hydroxylase (CYP21) by 38% and cytochrome P450 11beta-hydroxylase (CYP11B1) by 60%. The conversion of progesterone and pregnenolone was inhibited by 34% and 30%, respectively. Subsequent extractions with chloroform and methanol showed inhibition of substrate binding and conversion with hydrophobic compounds exhibiting a greater inhibitory effect on deoxycorticosterone binding to CYP11B1 (30%) and on progesterone binding to CYP21 (50%). The inhibition of binding of pregnenolone to CYP17 by the chloroform extract was 62%, with negligible inhibition by the methanol extract. The chloroform extract showed a greater inhibitory effect than the methanol extract on progesterone and pregnenolone metabolism (20%-50%).

Molecular cloning and expression of guinea pig cytochrome P450c21 cDNA (steroid 21-hydroxylase) isolated from the adrenals.

In mammals, the P450c21 enzyme mediates 21-hydroxylase activity by transforming progesterone and 17-hydroxyprogesterone into deoxycorticosterone (DOC) and 11-deoxycortisol (11-DOC), respectively. Previous studies have shown that among the adrenal steroid hydroxylase enzymes involved in C19 steroid and glucocorticoid syntheses, P450c21 plays an important role, because it is localized at the key branch between glucocorticoids and C19 steroid production. Its implication in congenital adrenal hyperplasia is also of great clinical interest. In this study, in addition to describing the isolation of the P450c21 cDNA from guinea pig (GP) adrenal and comparing it to those from other species, we report on its tissue-distribution and on the activity of the recombinant protein towards progesterone and 17-hydroxyprogesterone. The guinea pig P450c21 includes the full-length coding region (1464 nucleotide) that is translated to a protein of 488 amino acids. The clone shares highly conserved regions with other species. The guinea pig P450c21 cDNA hybridized with a major transcript of 2.1kb and with two minor related transcripts of 1.8 and 1.5 kb and was found to be adrenal-specific among the various tissues analyzed. Characterization of the enzymatic activity by transient transfection of the guinea pig P450c21 cDNA in human embryonic kidney 293 cells indicated a net preference for the 21-hydroxylation of 17-hydroxyprogesterone in comparison to the progesterone substrate. Assays showed a maximum conversion rate of 12.5% for the conversion of progesterone into deoxycorticosterone (mineralocorticoid pathway), whereas the guinea pig P450c21 demonstrated a higher activity with 17alpha-hydroxyprogesterone, with 55% of 11-deoxycortisol formation (glucocorticoid pathway) after 48 h. Adrenocorticotropin and an analogue of the second messenger cyclic adenosine monophosphate specifically increased the abundance of P450c21 mRNA levels in guinea pig adrenal cells.

Adrenocortical adenoma associated with inadequately treated congenital adrenal hyperplasia.

We report a 6 year-old boy with the simple virilizing form of 21-hydroxylase deficiency in whom an adrenal adenoma developed following 5 years of steroid treatment. Extremely high levels of basal serum 17alpha-hydroxyprogesterone as well as an exaggerated response of 17alpha-hydroxyprogesterone to adrenocorticotropic hormone confirmed congenital adrenal hyperplasia at 7 years of age. Initially elevated serum steroid levels were restrained by high dose hydrocortisone therapy, but he chronically tended to take inadequate doses of glucocorticoid. At 12 years of age an adenoma was found in the cortex of the hyperplastic right adrenal gland. The importance of early diagnosis and compliance with medication in the simple virilizing form of 21-hydroxylase deficiency is stressed.

Salt wasting in simple virilizing congenital adrenal hyperplasia.

OBJECTIVE: To evaluate possible derangement in sodium balance in patients with the simple virilizing (SV) form of congenital adrenal hyperplasia (CAH) which might have implications for therapeutic procedures. DESIGN: Patients were sodium loaded throughout the protocol and studied after interruption of cortisone therapy for 4 days, after treatment with dexamethasone 1 mg/m2/d for 3 days and after additional therapy with 9alpha-fluorocortisone (9alphaF) 0.1 mg/m2 for 3 days and 9alphaF 0.2 mg/m2 for 3 days. After each phase, basal and stimulated (2 h in an upright position), aldosterone and plasma renin concentrations (PRC) were evaluated. METHODS: Nine children aged 5.0 to 12.8 years with the clinical classification of SV CAH were studied. Diagnosis was established at the age of 2.9 +/- 1.9 years (mean +/- SD) and the patients were treated with oral hydrocortisone at a mean dose of 22.5 mg/m2/d, given in two or three daily doses. Seven patients were heterozygous for the Ile172Asn point mutation in exon 4, and two for the Pro30Leu mutation in exon 1 of the CYP21 gene. All of them had a more severe mutation or deletion in the second allele. PRC was determined by RIA and expressed as Goldblatt units (GU). Aldosterone was determined by RIA. Genotyping for disease-causing deletions and mutations was performed by Southern blot analysis, PCR and direct sequencing of CYP21. RESULTS: PRC was significantly higher in patients off hydrocortisone replacement therapy than in age matched control subjects (basal 3.3 +/- 0.5 vs 1.2 +/- 0.2 GU 10(-4)/ml [mean +/- SEM], p<0.001; stimulated 8.6 +/- 0.5 vs 2.4 +/- 0.4 GU 10(-4)/ml; p<0.05). Upon treatment with dexamethasone, patients with CAH demonstrated a decrease in basal (2.1 +/- 0.5 GU 10(-4)/ml) but not in stimulated PRC (8.8 +/- 2.6 GU 10(-4)/ml). When dexamethasone treatment was supplemented by 9alphaF, both supine (0.9 +/- 0.1 GU 10(-4)/ml) and stimulated (1.6 +/- 0.3 GU 10(-4)/ml) PRC were suppressed into the normal range. Aldosterone concentrations were elevated after interrupting hydrocortisone treatment only under basal conditions. Dexamethasone caused a decrease below the reference level and 9alphaF resulted in further suppression of aldosterone concentration. CONCLUSIONS: All patients were hemizygous for a CYP21 mutation that is usually considered not to be associated with clinically relevant salt loss. However, we demonstrated an aldosterone secretion disturbance in patients with SV CAH which cannot be corrected by glucocorticoid treatment alone. Additional mineralocorticoid therapy should be considered in order to suppress PRC and reduce the glucocorticoid dose required for adequate control.

Phytoestrogens alter adrenocortical function: genistein and daidzein suppress glucocorticoid and stimulate androgen production by cultured adrenal cortical cells.

Phytoestrogens influence a variety of biological processes. As 17beta-estradiol alters adrenocortical cell function, we examined whether the dietary phytoestrogens, genistein and daidzein, have related effects. In cultured human fetal and postnatal adrenal cortical cells, genistein and daidzein (both 0.4-40 micromol/L) decreased ACTH-stimulated cortisol production to basal levels (ED50, 1-4 micromol/L). In the adult adrenocortical cell line, H295, genistein, daidzein, and 17beta-estradiol (10 micromol/L) decreased cAMP-stimulated cortisol synthesis in a similar fashion. Neither genistein nor daidzein altered basal or ACTH-stimulated dehydroepiandosterone sulfate (DHEA-S) production in fetal adrenocortical cells, whereas in postnatal adrenocortical cells, DHEA and DHEA-S were markedly increased (ED50, 1-4 micromol/L). In H295 cells, basal and cAMP-stimulated DHEA production were similarly increased by the phytoestrogens and 17beta-estradiol. Genistein and daidzein did not affect the expression of steroid-metabolizing enzymes. However, genistein and daidzein specifically inhibited the activity of 21-hydroxylase (P450c21); the activities of other steroidogenic enzymes were not affected. Thus, phytoestrogens may decrease cortisol synthesis by suppressing the activity of P450c21 and, as a consequence, increase DHEA/DHEA-S synthesis by shunting metabolites away from the glucocorticoid synthetic pathway. Therefore, consumption of foods containing phytoestrogens may alter adrenocortical function by decreasing cortisol and increasing androgen production.