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Publication
Journal: Biochemical Journal
April/26/2001
Abstract
The kinetic parameters, steroid substrate specificity and identities of reaction products were determined for four homogeneous recombinant human 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD) isoforms of the aldo-keto reductase (AKR) superfamily. The enzymes correspond to type 1 3alpha-HSD (AKR1C4), type 2 3alpha(<em>17</em>beta)-HSD (AKR1C3), type 3 3alpha-HSD (AKR1C2) and 20alpha(3alpha)-HSD (AKR1C1), and share at least 84% amino acid sequence identity. All enzymes acted as NAD(P)(H)-dependent 3-, <em>17</em>- and 20-<em>ketosteroid</em> reductases and as 3alpha-, <em>17</em>beta- and 20alpha-hydroxysteroid oxidases. The functional plasticity of these isoforms highlights their ability to modulate the levels of active androgens, oestrogens and progestins. Salient features were that AKR1C4 was the most catalytically efficient, with k(cat)/K(m) values for substrates that exceeded those obtained with other isoforms by 10-30-fold. In the reduction direction, all isoforms inactivated 5alpha-dihydrotestosterone (<em>17</em>beta-hydroxy-5alpha-androstan-3-one; 5alpha-DHT) to yield 5alpha-androstane-3alpha,<em>17</em>beta-diol (3alpha-androstanediol). However, only AKR1C3 reduced Delta(4)-androstene-3,<em>17</em>-dione to produce significant amounts of testosterone. All isoforms reduced oestrone to <em>17</em>beta-oestradiol, and progesterone to 20alpha-hydroxy-pregn-4-ene-3,20-dione (20alpha-hydroxyprogesterone). In the oxidation direction, only AKR1C2 converted 3alpha-androstanediol to the active hormone 5alpha-DHT. AKR1C3 and AKR1C4 oxidized testosterone to Delta(4)-androstene-3,<em>17</em>-dione. All isoforms oxidized <em>17</em>beta-oestradiol to oestrone, and 20alpha-hydroxyprogesterone to progesterone. Discrete tissue distribution of these AKR1C enzymes was observed using isoform-specific reverse transcriptase-PCR. AKR1C4 was virtually liver-specific and its high k(cat)/K(m) allows this enzyme to form 5alpha/5beta-tetrahydrosteroids robustly. AKR1C3 was most prominent in the prostate and mammary glands. The ability of AKR1C3 to interconvert testosterone with Delta(4)-androstene-3,<em>17</em>-dione, but to inactivate 5alpha-DHT, is consistent with this enzyme eliminating active androgens from the prostate. In the mammary gland, AKR1C3 will convert Delta(4)-androstene-3,<em>17</em>-dione to testosterone (a substrate aromatizable to <em>17</em>beta-oestradiol), oestrone to <em>17</em>beta-oestradiol, and progesterone to 20alpha-hydroxyprogesterone, and this concerted reductive activity may yield a pro-oesterogenic state. AKR1C3 is also the dominant form in the uterus and is responsible for the synthesis of 3alpha-androstanediol which has been implicated as a parturition hormone. The major isoforms in the brain, capable of synthesizing anxiolytic steroids, are AKR1C1 and AKR1C2. These studies are in stark contrast with those in rat where only a single AKR with positional- and stereo-specificity for 3alpha-hydroxysteroids exists.
Publication
Journal: Psychosomatic Medicine
July/27/1995
Abstract
The following study tested the hypothesis that women with post-traumatic stress disorder (PTSD) related to childhood sexual abuse would display elevated norepinephrine-to-cortisol ratios similar to that found in male combat veterans diagnosed with PTSD. Twenty-four-hour urine samples were collected from 28 women: 11 women with PTSD who experienced childhood sexual abuse (PTSD+), 8 women who experienced childhood sexual abuse without PTSD (PTSD-), and 9 nonabused controls. All urine samples were tested for creatinine, total catecholamines, free-cortisol, and <em>17</em>-<em>ketosteroid</em> levels. Psychological testing validated that the PTSD+ group was significantly elevated on all three subscales of the Impact of Events Scale. Both abused groups (PTSD+ and PTSD-) showed a tendency for polyuria, and the PTSD+ group showed a tendency towards obesity. Thus, neuroendocrine values (micrograms/day) were adjusted by creatinine clearance rates (creatinine mg/day/kg body weight). The corrected values indicated that the PTSD+ group had significantly elevated daily levels of norepinephrine, epinephrine, dopamine, and cortisol. However, because of the parallel elevation in cortisol, the norepinephrine-to-cortisol ratio was not significantly elevated in the PTSD+ diagnosed women in contrast to the findings reported for male PTSD patients. This discrepancy may reflect an important gender difference, an interaction between gender and age at onset of the traumatic experience (childhood abuse in females vs. combat experience in young adult males), or physiological variation related to phase of the disorder.
Publication
Journal: Annals of Surgery
September/17/2007
Publication
Journal: CMAJ
January/28/1967
Abstract
A father and son are described with a condition characterized by benign hypertension, potassium deficiency, increased aldosterone secretion rate (ASR), raised plasma volume and suppressed plasma renin activity (PRA). There were intermittent elevations of urine <em>17</em>-<em>ketosteroids</em> and <em>17</em>-hydroxycorticoids (<em>17</em>-OHCS) but no increase in urine THS, normal circadian rhythm of plasma <em>17</em>-OHCS, and normal urine <em>17</em>-OHCS response to dexamethasone and intravenous ACTH. Plasma ACTH and corticosterone secretion were not elevated. Pregnanetriol excretion was normal but urine pregnanediol was increased. At operation on the father no adrenal tumour was found; the excised left adrenal weighed 7 g. and showed nodular cortical hyperplasia; juxtaglomerular cells showed only occasional granules. Following operation hypertension persisted and ASR was half the preoperative value. All abnormalities in father and son were relieved by dexamethasone (DM) 2 mg. daily. The condition recurred following cessation of DM but was relieved by a second course of treatment. No such response to DM was seen in a normal subject or in a patient with Conn's syndrome. For a number of reasons it is suggested that patients with hypertension, increased ASR and low PRA be given a trial of dexamethasone treatment before undergoing adrenal surgery.
Publication
Journal: Molecular and Cellular Endocrinology
May/31/2006
Abstract
Human aldo-keto reductases (AKR) of the 1A, 1B, 1C and 1D subfamilies are involved in the pre-receptor regulation of nuclear (steroid hormone and orphan) receptors by regulating the local concentrations of their lipophilic ligands. AKR1C3 is one of the most interesting isoforms. It was cloned from human prostate and the recombinant protein was found to function as a 3-, <em>17</em>- and 20-<em>ketosteroid</em> reductase with a preference for the conversion of Delta4-androstene-3,<em>17</em>-dione to testosterone implicating this enzyme in the local production of active androgens within the prostate. Using a validated isoform specific real-time RT-PCR procedure the AKR1C3 transcript was shown to be more abundant in primary cultures of epithelial cells than stromal cells, and its expression in stromal cells increased with benign and malignant disease. Using a validated isoform specific monoclonal Ab, AKR1C3 protein expression was also detected in prostate epithelial cells by immunoblot analysis. Immunohistochemical staining of prostate tissue showed that AKR1C3 was expressed in adenocarcinoma and surprisingly high expression was observed in the endothelial cells. These cells are a rich source of prostaglandin G/H synthase 2 (COX-2) and vasoactive prostaglandins (PG) and thus the ability of recombinant AKR1C enzymes to act as PGF synthases was compared. AKR1C3 had the highest catalytic efficiency (kcat/Km) for the 11-ketoreduction of PGD2 to yield 9alpha,11beta-PGF2 raising the prospect that AKR1C3 may govern ligand access to peroxisome proliferator activated receptor (PPARgamma). Activation of PPARgamma is often a pro-apoptotic signal and/or leads to terminal differentiation, while 9alpha,11beta-PGF2 is a pro-proliferative signal. AKR1C3 is potently inhibited by non-steroidal anti-inflammatory drugs suggesting that the cancer chemopreventive properties of these agents may be mediated either by inhibition of AKR1C3 or COX. To discriminate between these effects we developed potent AKR1C inhibitors based on N-phenylanthranilic acids that do not inhibit COX-1 or COX-2. These compounds can now be used to determine the role of AKR1C3 in producing two proliferative signals in the prostate namely testosterone and 9alpha,11beta-PGF2.
Publication
Journal: Molecular Endocrinology
December/10/1991
Abstract
The 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta HSD) enzyme catalyzes the oxidation and isomerization of delta 5-3 beta-hydroxysteroid precursors into delta 4-<em>ketosteroids</em>, thus leading to the formation of all classes of steroid hormones. In addition, 3 beta HSD catalyzes the interconversion of 3 beta-hydroxy- and 3-keto-5 alpha-androstane steroids. Clinical observations in patients with 3 beta HSD deficiency as well as our recent data obtained by Southern blot analysis using a human placental 3 beta HSD cDNA (type I) as probe suggested the existence of multiple related 3 beta HSD isoenzymes. We now report the isolation and characterization of a second type of cDNA clone (arbitrarily designated type II) encoding 3 beta HSD after screening of a human adrenal lambda gt22A library. The nucleotide sequence of 1676 basepairs of human 3 beta HSD type II cDNA predicts a protein of 371 amino acids with a calculated molecular mass of 41,921 daltons, which displays 93.5% and 96.2% homology with human placental type I and rhesus macaque ovary 3 beta HSD deduced proteins, respectively. To characterize and compare the kinetic properties of the two isoenzymes, plasmids derived from pCMV and containing type I or type II 3 beta HSD full-length cDNA inserts were transiently expressed in HeLa human cervical carcinoma cells. In vitro incubation with NAD+ and 3H-labeled pregnenolone or dehydroepiandrosterone shows that the type I protein possesses a 3 beta HSD/delta 5-delta 4 isomerase activity higher than type II, with respective Km values of 0.24 vs. 1.2 microM for pregnenolone and 0.18 vs. 1.6 microM for dihydroepiandrosterone, while the specific activity of both types is equivalent. Moreover, incubation in the presence of NADH of homogenates from cells transfected with type I or type II 3 beta HSD indicates that dihydrotestosterone is converted into 5 alpha-androstane-3 beta, <em>17</em> beta-diol, with Km values of 0.26 and 2.7 microM, respectively. Ribonuclease protection assay using type I- and type II-specific cRNA probes revealed that type II transcripts are the almost exclusive 3 beta HSD mRNA species in the human adrenal gland, ovary, and testis, while type I transcripts correspond to the almost exclusive 3 beta HSD mRNA species in the placenta and skin and represent the predominantly expressed species in mammary gland tissue. The present data show for the first time that adrenals and gonads express a type of 3 beta HSD isoenzyme that is distinct from the type expressed in the placenta.(ABSTRACT TRUNCATED AT 400 WORDS)
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
February/15/2004
Authors
Publication
Journal: Endocrinology
July/22/2003
Abstract
Human aldo-keto reductases (AKRs) of the AKR1C subfamily function in vitro as 3-keto-, <em>17</em>-keto-, and 20-<em>ketosteroid</em> reductases or as 3alpha-, <em>17</em>beta-, and 20alpha-hydroxysteroid oxidases. These AKRs can convert potent sex hormones (androgens, estrogens, and progestins) into their cognate inactive metabolites or vice versa. By controlling local ligand concentration AKRs may regulate steroid hormone action at the prereceptor level. AKR1C2 is expressed in prostate, and in vitro it will catalyze the nicotinamide adenine dinucleotide (NAD(+))-dependent oxidation of 3alpha-androstanediol (3alpha-diol) to 5alpha-dihydrotestosterone (5alpha-DHT). This reaction is potently inhibited by reduced NAD phosphate (NADPH), indicating that the NAD(+): NADPH ratio in cells will determine whether AKR1C2 makes 5alpha-DHT. In transient COS-1-AKR1C2 and in stable PC-3-AKR1C2 transfectants, 5alpha-DHT was reduced by AKR1C2. However, the transfected AKR1C2 oxidase activity was insufficient to surmount the endogenous <em>17</em>beta-hydroxysteroid dehydrogenase (<em>17</em>beta-HSD) activity, which eliminated 3alpha-diol as androsterone. PC-3 cells expressed retinol dehydrogenase/3alpha-HSD and 11-cis-retinol dehydrogenase, but these endogenous enzymes did not oxidize 3alpha-diol to 5alpha-DHT. In stable LNCaP-AKR1C2 transfectants, AKR1C2 did not alter androgen metabolism due to a high rate of glucuronidation. In primary cultures of epithelial cells, high levels of AKR1C2 transcripts were detected in prostate cancer, but not in cells from normal prostate. Thus, in prostate cells AKR1C2 acts as a 3-<em>ketosteroid</em> reductase to eliminate 5alpha-DHT and prevents activation of the androgen receptor. AKR1C2 does not act as an oxidase due to either potent product inhibition by NADPH or because it cannot surmount the oxidative <em>17</em>beta-HSD present. Neither AKR1C2, retinol dehydrogenase/3alpha-HSD nor 11-cis-retinol dehydrogenase is a source of 5alpha-DHT in PC-3 cells.
Publication
Journal: Biology of Reproduction
May/18/1995
Abstract
The Leydig cell of the testis is the only cell in the male that has the capacity to synthesize testosterone from cholesterol. Testosterone is critical during fetal development for male sexual differentiation, and postnatally for initiation and maintenance of spermatogenesis and the expression of the male secondary sex characteristics. The biosynthesis of testosterone requires the activities of four enzymes, cholesterol side-chain cleavage enzyme (P450scc), 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta HSD), <em>17</em> alpha-hydroxylase/C<em>17</em>-20 lyase (P450(<em>17</em> alpha)), and <em>17</em>-<em>ketosteroid</em> reductase. The expression of these enzymes appears to be regulated by different mechanisms. The recent isolation of the mouse cDNAs and structural genes that encode these enzymes has enabled us to begin to investigate the regulation of their expression at the molecular level. This review discusses the regulation by cAMP and steroids of three enzymes in Leydig cells, P450scc, P450(<em>17</em> alpha), and 3 beta HSD, as well as characterization of the promoters of the mouse genes that encode P450scc and P450(<em>17</em> alpha).
Publication
Journal: Journal of Steroid Biochemistry and Molecular Biology
April/24/2012
Abstract
Steroid degradation by Comamonas testosteroni and Nocardia restrictus have been intensively studied for the purpose of obtaining materials for steroid drug synthesis. C. testosteroni degrades side chains and converts single/double bonds of certain steroid compounds to produce androsta-1,4-diene 3,<em>17</em>-dione or the derivative. Following 9α-hydroxylation leads to aromatization of the A-ring accompanied by cleavage of the B-ring, and aromatized A-ring is hydroxylated at C-4 position, cleaved at Δ4 by meta-cleavage, and divided into 2-hydroxyhexa-2,4-dienoic acid (A-ring) and 9,<em>17</em>-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid (B,C,D-ring) by hydrolysis. Reactions and the genes involved in the cleavage and the following degradation of the A-ring are similar to those for bacterial biphenyl degradation, and 9,<em>17</em>-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid degradation is suggested to be mainly β-oxidation. Genes involved in A-ring aromatization and degradation form a gene cluster, and the genes involved in β-oxidation of 9,<em>17</em>-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid also comprise a large cluster of more than 10 genes. The DNA region between these two main steroid degradation gene clusters contain 3α-hydroxysteroid dehydrogenase gene, Δ5,3-<em>ketosteroid</em> isomerase gene, genes for inversion of an α-oriented-hydroxyl group to a β-oriented-hydroxyl group at C-12 position of cholic acid, and genes possibly involved in the degradation of a side chain at C-<em>17</em> position of cholic acid, indicating this DNA region of more than 100kb to be a steroid degradation gene hot spot of C. testosteroni. Article from a special issue on steroids and microorganisms.
Publication
Journal: Journal of Molecular Endocrinology
September/22/1999
Abstract
A number of enzymes possessing <em>17</em>beta-hydroxysteroid dehydrogenase/<em>17</em>-<em>ketosteroid</em> reductase (<em>17</em>HSD/KSR) activities have been described and cloned, but their nomenclature needs specification. To clarify the present situation, descriptions of the eight cloned <em>17</em>HSD/KSRs are given and guidelines for the classification of novel <em>17</em>HSD/KSR enzymes are presented.
Publication
Journal: Molecular and Cellular Endocrinology
October/21/2004
Abstract
Four soluble human 3 alpha-hydroxysteroid dehydrogenase (HSD) isoforms exist which are aldo-keto reductase (AKR) superfamily members. They share 86% sequence identity and correspond to: AKR1C1 (20 alpha(3 alpha)-HSD); AKR1C2 (type 3 3 alpha-HSD and bile-acid binding protein); AKR1C3 (type 2 3 alpha-HSD and type 5 <em>17</em> beta-HSD); and AKR1C4 (type 1 3 alpha-HSD). Each of the homogeneous recombinant enzymes are plastic and display 3-, <em>17</em>- and 20-<em>ketosteroid</em> reductase and 3 alpha- <em>17</em> beta- and 20 alpha-hydroxysteroid oxidase activities with different k(cat)/K(m) ratios in vitro. The crystal structure of the AKR1C2.NADP(+).ursodeoxycholate complex provides an explanation for this functional plasticity. Ursodeoxycholate is bound backwards (D-ring in the A-ring position) and upside down (beta-face of steroid inverted) relative to the position of 3-<em>ketosteroids</em> in the related rat liver 3 alpha-HSD (AKR1C9) structure. Transient transfection indicates that in COS-1 cells, AKR1C enzymes function as <em>ketosteroid</em> reductases due to potent inhibition of their oxidase activity by NADPH. By acting as <em>ketosteroid</em> reductases they may regulate the occupancy of the androgen, estrogen and progesterone receptors. RT-PCR showed that AKRs are discretely localized. AKR1C4 is virtually liver specific, while AKR1C2 and AKR1C3 are dominantly expressed in prostate and mammary gland. AKR1C genes are highly conserved in structure and may be transcriptionally regulated by steroid hormones and stress.
Publication
Journal: Fertility and Sterility
June/6/1990
Abstract
Polycystic ovarian syndrome (PCOS) appears to be due to a previously unrecognized type of steroidogenic abnormality, one in which hyperandrogenism arises from a regulatory abnormality (dysregulation) rather than from enzyme deficiency. It appears that PCOS typically arises from masculinized regulation of the androgen-forming enzyme (cytochrome P450c<em>17</em> alpha) within ovarian thecal cells. This may arise by either excessive stimulation by luteinizing hormone (LH) or by escape from desensitization to LH. We review evidence which is compatible with the concept that the latter situation may result from an intrinsic intraovarian flaw in the paracrine feedback mechanism by which thecal androgen biosynthesis is inhibited and that coexistent adrenal <em>17</em>-<em>ketosteroid</em> hyper-responsiveness to corticotropin (ACTH) may be due to a similar type of dysregulation of adrenocortical P450c<em>17</em> alpha.
Publication
Journal: American Journal of Medicine
January/9/1982
Abstract
We reviewed 150 findings in 58 patients (14 males and 44 females) with adrenocortical tumors (26 with adenoma and 32 with carcinoma) admitted to Vanderbilt Hospital during 28 years. In general, our findings agree with those reported by others in multi-institutional series or literature reviews. Adenomas took longer to diagnose than carcinomas. Adenomas usually caused Cushing's syndrome, but two caused virilization and three caused no endocrine syndrome. There was no difference in time required for diagnosis of carcinoma in men or women or in those with Cushing's syndrome, virilization or no endocrine syndrome. Urinary <em>17</em>-hydroxycorticoid (<em>17</em>-OHCS) levels were similar in those with adenoma and those with carcinoma, but <em>17</em>-<em>ketosteroid</em> (<em>17</em>-KS) levels were usually less than 20 mg per day in patients with adenoma and greater than 20 mg per day in patients with carcinoma. Adenomas were uniformly independent of endogenous ACTH stimulation, but frequently responded to exogenous ACTH. As with adenomas, no carcinoma demonstrated normal suppression with dexamethasone or normal response to metyrapone, but only one responded to exogenous ACTH. Some patients had no clinical Cushing's syndrome despite high levels of plasma cortisol and urine <em>17</em>-OHCS. "Nonfunctional" tumors probably merely secreted insufficient steroids to cause signs and symptoms. Patients with adenoma were uniformly cured by surgical tumor resection. Occasional patients with carcinoma enjoyed long survival despite incomplete resection of their tumors, but most patients died of recurrent of metastatic carcinoma within seven years, often within a year of two. Small tumor size and benign histologic features were insufficient to predict benign clinical behavior. The adrenocorticolytic drug, o,p'DDD, offered objective remission for only an occasional patient.
Publication
Journal: Biology of Reproduction
November/20/2000
Abstract
This article summarizes a talk on Leydig cell aging presented at the 1999 Annual Meeting of the Society for the Study of Reproduction. In the Brown Norway rat, serum testosterone levels decrease with aging, accompanied by increases in serum FSH. The capacity of Leydig cells to produce testosterone is higher in young than in old rats. Binding studies with hCG revealed reduced receptor number in old vs. young Leydig cells. In response to incubation with LH, cAMP production was found to be reduced in old vs. young Leydig cells, indicating that signal transduction mechanisms in the old cells are affected by aging. Steroidogenic acute regulatory protein and mRNA levels are reduced in old Leydig cells, suggesting that there may be deficits in the transport of cholesterol to the inner mitochondrial membrane of aged cells. The activity of P450 side-chain cleavage enzyme is reduced in old vs. young cells, as are the activities of each of 3beta-hydroxysteroid dehydrogenase, <em>17</em>alpha-hydroxylase/C<em>17</em>-20 lyase, and <em>17</em>-<em>ketosteroid</em> reductase. Serum LH levels do not differ between young and old rats, and the administration of LH failed to induce old Leydig cells to produce high (young) testosterone levels, suggesting that the cause of age-related reductions in steroidogenesis is not LH deficits. We hypothesized that reactive oxygen, produced as a by-product of steroidogenesis itself, might be responsible for age-related reductions in testosterone production by the Leydig cells. Consistent with this, long-term suppression of steroidogenesis was found to prevent or delay the reduced steroidogenesis that accompanies Leydig cell aging. A possible explanation of this finding is that long-term suppression of steroidogenesis prevents free radical damage to the cells by suppressing the production of the reactive oxygen species that are a by-product of steroidogenesis itself.
Publication
Journal: Endocrinology
July/20/2000
Abstract
The final step in the biosynthesis of testosterone is reduction of androstenedione by the enzyme <em>17</em>beta-hydroxysteroid dehydrogenase/ <em>17</em>-<em>ketosteroid</em> reductase (<em>17</em>betaHSD/<em>17</em>KSR). In this study, we have examined expression of the four known reductive isoforms of <em>17</em>betaHSD/ <em>17</em>KSR (types 1, 3, 5, and 7) in the developing mouse testis and have determined changes in the localization of isoform expression and testosterone secretion during development. Using RT-PCR isoforms 1, 3, and 7 were shown to be expressed in the seminiferous tubules of neonatal testis, whereas isoforms 3 and 7 were expressed in the interstitial tissue of the adult testis. The type 7 isoform is unlikely to be involved in androgen synthesis and further study concentrated on the type 3 isoform. Developmentally, isoform type 3 was expressed in the seminiferous tubules up to day 10, showed little or no expression on day 20 and from day 30 was confined to the interstitial tissue. In situ hybridization confirmed that the type 3 isoform was expressed only in the seminiferous tubules in fetal testes and in the interstitial tissue in adult testes. In accordance with the localization of enzyme messenger RNA expression <em>17</em>-<em>ketosteroid</em> reductase enzyme activity was very low in isolated interstitial tissue from neonatal testes while interstitial tissue from adult testes showed high activity. Seminiferous tubules from both neonatal and adult testes showed high levels of enzyme activity. The major androgen secreted by the interstitial tissue of prepubertal animals was androstenedione up to day 20 while 5alpha-androstanediol and/or testosterone were the major androgens secreted from day 30 onwards. These results show that fetal Leydig cells do not express significant levels of a reductive isoform of <em>17</em>betaHSD/ <em>17</em>KSR and that androstenedione is the major androgen secreted by these cells. Production of testosterone up until puberty is dependent upon <em>17</em>betaHSD/<em>17</em>KSR activity in the seminiferous tubules--a "two cell" requirement for testosterone synthesis. Expression of the <em>17</em>betaHSD/<em>17</em>KSR type 3 isoform (the main reductive isoform in the testis) declines in the seminiferous tubules before puberty but then reappears in the developing adult Leydig cell population.
Publication
Journal: Pediatrics
October/31/2000
Abstract
OBJECTIVE
To assess whether treatment of virilizing congenital adrenal hyperplasia (CAH) with long-acting glucocorticoids is associated with favorable growth outcomes.
METHODS
We examined the long-term growth of <em>17</em> boys and 9 girls with CAH treated with dexamethasone (.27 +/-.01 mg/m(2)/day).
RESULTS
For individuals with comparable bone age (BA) and chronological age (CA) at the onset of dexamethasone therapy, males were 2.8 +/-.8 years (mean +/- standard error of the mean; n = 13) and females were 2.4 +/- 1.0 years (n = 6). Males were treated for 7.3 +/- 1.1 years (DeltaCA) over which time the change in BA (DeltaBA) was 7.0 +/- 1.3 years, and the change in height age (DeltaHA) was 6.9 +/- 1.1 years. Females were treated for 6.8 +/- 1.3 years, over which time the DeltaBA was 6.5 +/- 1.0 years, and the DeltaHA was 6.3 +/-.8 years. During treatment <em>17</em> <em>ketosteroid</em> excretion rates were normal for age and <em>17</em>-hydroxyprogesterone values were 69.6 +/- 18 ng/dL. Testicular enlargement was first detected at 10.7 +/-.8 years and breast tissue at 9.9 +/- 1.2 years. Three boys and 1 girl had final heights of <em>17</em>1. 8 +/- 6 cm and 161 cm, respectively, compared with midparental heights of <em>17</em>6.1 +/- 4.1 cm and 160 cm. Predicted adult heights for 6 other boys and 5 girls were <em>17</em>6.8 +/- 2.0 cm and 161.4 +/- 2.8 cm, respectively, compared with midparental heights of <em>17</em>4.6 +/- 1.4 cm and 158.2 +/- 2.0 cm. Statural outcomes were less favorable for 7 children started on dexamethasone when BAs were considerably advanced, although height predictions increased during therapy.
CONCLUSIONS
These observations show that children treated with dexamethasone for CAH can achieve normal growth with the convenience of once-a-day dosing in most cases.congenital adrenal hyperplasia, dexamethasone, growth.
Publication
Journal: Clinical Endocrinology
March/20/1997
Abstract
OBJECTIVE
Incidentally discovered adrenal masses are fairly common, although there are some controversies concerning the results of hormonal investigation (especially DHEAS values) and the methods of management. We summarize our experience in diagnosis, pathological findings and treatment of a large group of patients with incidentally found adrenal tumours.
METHODS
Our study included patients referred to the Department of Endocrinology of the Centre of Post-graduate Medical Education (Warsaw, Poland) during the last 10 years because of an adrenal tumour incidentally found on ultrasound scan. In all cases this was confirmed by computed tomography. There were 208 patients (148 female and 60 male), 14-76 years old. Unilateral adrenal masses were found in <em>17</em>2 patients (right 106, left 66), while bilateral masses were demonstrated in 36 patients. The size of the tumours ranged between 0.8 and 21.0 cm. The most common clinical abnormalities were hypertension (36 cases), obesity (23 cases), diabetes (8 cases), Addison's disease (6 cases).
METHODS
Endocrine tests evaluating pituitary-adrenal function (urinary excretion of <em>17</em>-hydroxycorticosteroids, <em>17</em>-<em>ketosteroids</em> and catecholamines, plasma concentrations of ACTH, cortisol, DHEAS, androstendione and testosterone, dexamethasone suppression test and corticotrophin-releasing hormone stimulation test).
RESULTS
Cortisol hypersecretion was noted in two patients with coexisting Cushing's disease and high normal <em>17</em>-OHCS values with lack of dexamethasone suppressibility were found in six other patients with pre-clinical Cushing's syndrome. More common were subtle hormonal abnormalities: low ACTH levels (in 33 out of 98 investigated patients), diminished dexamethasone suppressibility and lack of ACTH response in the CRH test (in two out of 12 patients). Urinary catecholamine excretion was elevated in nine patients. In the group of 85 patients treated by surgery the most frequent pathological findings were: adrenocortical adenoma (21), carcinoma (<em>17</em>), phaeochromocytoma (13), metastatic masses (12) and myelolipoma (10). The size of carcinomas ranged from 3.2 to 20.0 cm, while the size of non-malignant tumours ranged from 1.5 to 21.0 cm.
CONCLUSIONS
Every patient with an incidentally discovered adrenal mass has to be investigated to detect malignancy and subtle hormonal overproduction, to select the cases for surgical treatment. Most of the adrenocortical carcinomas were>> 7.0 cm in diameter. For prophylactic purposes, adrenal incidentalomas>> 4.0 cm should be treated by surgery, while the smaller ones could be followed-up (with special care for those between 3.0 and 4.0 cm).
Publication
Journal: Journal of Biological Chemistry
January/16/2012
Abstract
Mycobacterium tuberculosis (Mtb), a significant global pathogen, contains a cholesterol catabolic pathway. Although the precise role of cholesterol catabolism in Mtb remains unclear, the Rieske monooxygenase in this pathway, 3-<em>ketosteroid</em> 9α-hydroxylase (KshAB), has been identified as a virulence factor. To investigate the physiological substrate of KshAB, a rhodococcal acyl-CoA synthetase was used to produce the coenzyme A thioesters of two cholesterol derivatives: 3-oxo-23,24-bisnorchol-4-en-22-oic acid (forming 4-BNC-CoA) and 3-oxo-23,24-bisnorchola-1,4-dien-22-oic acid (forming 1,4-BNC-CoA). The apparent specificity constant (k(cat)/K(m)) of KshAB for the CoA thioester substrates was 20-30 times that for the corresponding <em>17</em>-keto compounds previously proposed as physiological substrates. The apparent K(m)(O(2)) was 90 ± 10 μM in the presence of 1,4-BNC-CoA, consistent with the value for two other cholesterol catabolic oxygenases. The Δ(1) <em>ketosteroid</em> dehydrogenase KstD acted with KshAB to cleave steroid ring B with a specific activity eight times greater for a CoA thioester than the corresponding ketone. Finally, modeling 1,4-BNC-CoA into the KshA crystal structure suggested that the CoA moiety binds in a pocket at the mouth of the active site channel and could contribute to substrate specificity. These results indicate that the physiological substrates of KshAB are CoA thioester intermediates of cholesterol side chain degradation and that side chain and ring degradation occur concurrently in Mtb. This finding has implications for steroid metabolites potentially released by the pathogen during infection and for the design of inhibitors for cholesterol-degrading enzymes. The methodologies and rhodococcal enzymes used to generate thioesters will facilitate the further study of cholesterol catabolism.
Publication
Journal: Journal of Clinical Investigation
October/28/1970
Abstract
This is the first report of a male with <em>17</em>alpha-hydroxylase deficiency resulting in male pseudohermaphroditism, ambiguous external genitalia, absence of male secondary sexual characteristics, and gynecomastia at puberty. Diagnosis was based on extensive studies of steroid metabolism including the following: low urinary excretion of <em>17</em>-<em>ketosteroids</em> and <em>17</em>-hydroxycorticoids which did not increase after ACTH; no response of very low plasma testosterone and dehydroepiandrosterone to adrenocorticotropin (ACTH) or chorionic gonadotropin; and low urinary aldosterone and plasma renin which increased after dexamethasone. Secretion rates of <em>17</em>-hydroxylated steroids, cortisol (F) and 11-desoxycortisol (S), were very low while desoxycorticosterone (DOC) and corticosterone (B) secretion rates were increased sevenfold. Results expressed as milligrams per meter squared per day were as follows: F, 1.3; S, 0.023; DOC, 0.35; and B, 16 (mean normal values were F, 7.5; S, 0.26; DOC, 0.055, and B, 2.2). Plasma gonadotropins were markedly increased (FSH, 106; LH, 364 mIU/ml). Testicular biopsies revealed interstitial-cell hyperplasia and early spermatogenesis. Karyotype was 46/XY. Pedigree showed no other affected member. At laparotomy ovaries, uterus, and fallopian tubes were absent, vas deferens was incomplete, and prostate was present. External genitalia consisted of small phallus, bifid scrotum, third-degree hypospadias, and small vagina. At puberty there was no growth of body hair or phallic enlargement. Biopsy of marked gynecomastia showed both ducts and acini. Testosterone administration produced virilization. Sexual ambiguity demonstrates strong dependence of external genitalia on androgens for male differentiation. Suppression of Müllerian structures occurred despite female levels of testosterone indicating this step in male differentiation is not testosterone dependent. Pubertal breast development in this male supports the concept of femaleness during ontogeny unless counteracted by male factors. Diagnosis of other adrenocortical enzymatic deficiencies is excluded by the steroidal studies. The clinical response to testosterone excludes testicular feminization. Deficiency of <em>17</em>-hydroxylation must be added to the cause of male pseudohermaphroditism.
Authors
Publication
Journal: Steroids
August/26/2014
Abstract
Human aldo-keto reductases AKR1C1-AKR1C4 and AKR1D1 play essential roles in the metabolism of all steroid hormones, the biosynthesis of neurosteroids and bile acids, the metabolism of conjugated steroids, and synthetic therapeutic steroids. These enzymes catalyze NADPH dependent reductions at the C3, C5, C<em>17</em> and C20 positions on the steroid nucleus and side-chain. AKR1C1-AKR1C4 act as 3-keto, <em>17</em>-keto and 20-<em>ketosteroid</em> reductases to varying extents, while AKR1D1 acts as the sole Δ(4)-3-<em>ketosteroid</em>-5β-reductase (steroid 5β-reductase) in humans. AKR1 enzymes control the concentrations of active ligands for nuclear receptors and control their ligand occupancy and trans-activation, they also regulate the amount of neurosteroids that can modulate the activity of GABAA and NMDA receptors. As such they are involved in the pre-receptor regulation of nuclear and membrane bound receptors. Altered expression of individual AKR1C genes is related to development of prostate, breast, and endometrial cancer. Mutations in AKR1C1 and AKR1C4 are responsible for sexual development dysgenesis and mutations in AKR1D1 are causative in bile-acid deficiency.
Publication
Journal: Hoppe-Seyler's Zeitschrift fur physiologische Chemie
February/15/2004
Publication
Journal: Clinical Endocrinology
February/28/1986
Abstract
Two siblings, a 9-week-old female and an 18-year-old male pseudohermaphrodite are described with deficient cholesterol side-chain cleavage activity. The female died untreated in 1954; the second sibling, a phenotypically female infant with 46 XY karyotype, was diagnosed at age 5 weeks. Massive adrenal hyperplasia was revealed by intravenous pyelography showing downward displacement of the kidneys. Secretion rates of cortisol, aldosterone, deoxycorticosterone and corticosterone were unmeasurable. Urinary <em>17</em>-hydroxycorticosteroids (<em>17</em>-OHCS), tetrahydrocortisol, <em>17</em>-<em>ketosteroids</em> (<em>17</em>-KS), pregnanetriol, pregnanediol, and delta 5-3 beta-ol steroids were not detected during prolonged administration of ACTH. Plasma concentrations and urinary excretion of gonadotrophins were increased. Gonadal mitochondria did not convert radiolabelled cholesterol to pregnenolone. The gluccocorticoid and mineralocorticoid deficiencies have been controlled well by steroid replacement therapy. Plasma ACTH concentrations and plasma renin activity remained strikingly elevated even when supraphysiologic doses of glucocorticoids and mineralocorticoids were given. Oestrogen replacement alone induced a pubertal growth spurt. The differential diagnosis, the effects of long-term steroid replacement therapy, and comparison with previously reported findings are discussed.
Publication
Journal: Brazilian Journal of Medical and Biological Research
November/16/2000
Abstract
Childhood adrenocortical tumors (ACT) are rare. In the USA, only about 25 new cases occur each year. In Southern Brazil, however, approximately 10 times that many cases are diagnosed each year. Most cases occur in the contiguous states of São Paulo and Paraná. The cause of this higher rate has not been identified. Familial genetic predisposition to cancer (p53 mutations) and selected genetic syndromes (Beckwith-Wiedemann syndrome) have been associated with childhood ACT in general but not with the Brazilian counterpart. Most of the affected children are young girls with classic endocrine syndromes (virilizing and/or Cushing). Levels of urinary <em>17</em>-<em>ketosteroids</em> and plasma dehydroepiandrosterone sulfate (DHEA-S), which are abnormal in approximately 90% of the cases, provide the pivotal clue to a diagnosis of ACT. Typical imaging findings of pediatric ACT consist of a large, well-defined suprarenal tumor containing calcifications with a thin capsule and central necrosis or hemorrhage. The pathologic classification of pediatric ACT is troublesome. Even an experienced pathologist can find it difficult to differentiate carcinoma from adenoma. Surgery is the single most important procedure in the successful treatment of ACT. The role of chemotherapy in the management of childhood ACT has not been established although occasional tumors are responsive to mitotane or cisplatin-containing regimens. Because of the heterogeneity and rarity of the disease, prognostic factors have been difficult to establish in pediatric ACT. Patients with incomplete tumor resection or with metastatic disease at diagnosis have a dismal prognosis. In patients with localized and completely resected tumors, the size of the tumor has predictive value. Patients with large tumors have a much higher relapse rate than those with small tumors.
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