Inhibition Of 11β-hydroxysteroid Dehydrogenase Research Articles

Inhibition of 11β-hydroxysteroid dehydrogenase 1 relieves fibrosis through depolarizing of hepatic stellate cell in NASH

11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) is a key enzyme that catalyzes the intracellular conversion of cortisone to physiologically active cortisol. Although 11βHSD1 has been implicated in numerous metabolic syndromes, such as obesity and diabetes, the functional roles of 11βHSD1 during progression of nonalcoholic steatohepatitis (NASH) and consequent fibrosis have not been fully elucidated. We found that pharmacological and genetic inhibition of 11βHSD1 resulted in reprogramming of hepatic stellate cell (HSC) activation via inhibition of p-SMAD3, α-SMA, Snail, and Col1A1 in a fibrotic environment and in multicellular hepatic spheroids (MCHSs). We also determined that 11βHSD1 contributes to the maintenance of NF-κB signaling through modulation of TNF, TLR7, ITGB3, and TWIST, as well as regulating PPARα signaling and extracellular matrix accumulation in activated HSCs during advanced fibrogenesis in MCHSs. Of great interest, the 11βHSD1 inhibitor J2H-1702 significantly attenuated hepatic lipid accumulation and ameliorated liver fibrosis in diet- and toxicity-induced NASH mouse models. Together, our data indicate that J2H-1702 is a promising new clinical candidate for the treatment of NASH.

Cadmium induces placental glucocorticoid barrier damage by suppressing the cAMP/PKA/Sp1 pathway and the protective role of taurine

Cadmium (Cd) exposure during pregnancy damages the placental glucocorticoid (GC) barrier, exposes the foetus to excess corticosterone (CORT) levels, and eventually inhibits foetal development. In addition, taurine (Tau) alleviates the toxicity of Cd on liver and kidney, but limited data are available on the role of Tau against the toxicity of heavy metals on female reproduction and fetal development. The present study was conducted to investigate the specific mechanism of Cd-induced placental GC barrier damage and the protective role of Tau. Pregnant rats were administered CdCl2 (1 mg/kg/day) and Tau (100, 200, or 300 mg/kg/day) by gavage from gestational day (GD) 0 to 19. The data showed that CdCl2 increased the foetal growth restriction (FGR) rate of the offspring, and the levels of CORT in the placental, maternal and foetal serum. Treatment with Tau significantly reversed the impact of Cd on both maternal and fetal parameters. Additionally, Tau can attenuate Cd-induced inhibition of 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) and specificity protein 1 (Sp1) in vivo and vitro. Furthermore, Sp1-siRNA alone reduced 11β-HSD2 levels and had a further inhibitory effect when the cells were treated with Cd simultaneously. Moreover, Cd suppressed cAMP/PKA signalling. Forskolin (adenylate cyclase agonist) pretreatment activated cAMP/PKA signalling and restored the Cd-induced downregulation of Sp1 and 11β-HSD2. Tau alleviated the Cd-induced decrease of Sp1 via activating cAMP/PKA signalling. Therefore, the results highlight that Tau protects against Cd-induced impairments in GC barrier damage by upregulating the cAMP/PKA/Sp1 pathway in placental trophoblasts.

Species-specific differences in the inhibition of 11β-hydroxysteroid dehydrogenase 2 by itraconazole and posaconazole

11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) converts active 11β-hydroxyglucocorticoids to their inactive 11-keto forms, thereby preventing inappropriate mineralocorticoid receptor activation by glucocorticoids. Disruption of 11β-HSD2 activity by genetic defects or inhibitors causes the syndrome of apparent mineralocorticoid excess (AME), characterized by hypokalemia, hypernatremia and hypertension. Recently, the azole antifungals itraconazole and posaconazole were identified to potently inhibit human 11β-HSD2, and several case studies described patients with acquired AME. To begin to understand why this adverse drug effect was missed during preclinical investigations, the inhibitory potential of itraconazole, its main metabolite hydroxyitraconazole (OHI) and posaconazole against 11β-HSD2 from human and three commonly used experimental animals was assessed. Whilst human 11β-HSD2 was potently inhibited by all three compounds (IC50 values in the nanomolar range), the rat enzyme was moderately inhibited (1.5- to 6-fold higher IC50 values compared to human), and mouse and zebrafish 11β-HSD2 were very weakly inhibited (IC50 values above 7 μM). Sequence alignment and application of newly generated homology models for human and mouse 11β-HSD2 revealed significant differences in the C-terminal region and the substrate binding pocket. Exchange of the C-terminus and substitution of residues Leu170,Ile172 in mouse 11β-HSD2 by the corresponding residues His170,Glu172 of the human enzyme resulted in a gain of sensitivity to itraconazole and posaconazole, resembling human 11β-HSD2. The results provide an explanation for the observed species-specific 11β-HSD2 inhibition by the studied azole antifungals. The obtained structure-activity relationship information should facilitate future assessments of 11β-HSD2 inhibitors and aid choosing adequate animal models for efficacy and safety studies.

SAT-344 11α-Hydroxyprogesterone, a Potent 11β-Hydroxysteroid Dehydrgenase Inhibitor, Is Metabolised In Vitro by Adrenal Steroidogenic Enzymes

The C11-oxy C21 steroids, 11αOHP4 (11α-hydroxyprogesterone) and 11βOHP4 (11β-hydroxyprogesterone), have to date been characterised only in terms of their inhibition of 11β-hydroxysteroid dehydrogenase (11βHSD). However, 11βOHP4 is also a substrate of 11βHSD2 and is converted to 11-ketoprogesterone which is subsequently metabolised to active C11-oxy androgens. Although our studies indicate that 11αOHP4 is not a substrate for 11βHSD2, it may be metabolised by the steroidogenic enzymes of the backdoor pathway. While circulating 11αOHP4 and 11βOHP4 levels are not routinely analysed in physiological and pathophysiological conditions, 11βOHP4 was only recently included in the analysis of steroid hormones associated with adrenal disorders with 11αOHP4 being overlooked. We have demonstrated that both 11αOHP4 and 11βOHP4 are present in prostate cancer tissue samples while the in vitro metabolism of 11βOHP4 contributes to the production of the potent C11-oxy C19 steroid, 11-ketodihydrotestosterone, in the C11-oxy backdoor pathway. We therefore hypothesised that 11αOHP4 would be metabolised to C11-oxy C19 steroids. The in vitro metabolism of 11αOHP4 was therefore assayed in HEK293 cells transiently transfected with 5α-reductase (SRD5A) and cytochrome P450 17A1 (CYP17A1). Ultra-performance convergence chromatography tandem mass spectrometry (UPC2-MS/MS) analysis identified 5α-pregnan-11α-ol-3,20-dione in the conversion by SRD5A1 and SRD5A2 (50% converted in 2.5 and 1.5 hrs, respectively), the initial step in the backdoor pathway. Moreover, novel steroid metabolites were detected in the metabolism of 11αOHP4 by CYP17A1 in the production of the 11α-hydroxy derivatives of 21-deoxycortisol and 11-hydroxyandrostenedione. These were successfully confirmed by UPC2-MS/MS and chromatographically separated from the 11β-hydroxylated forms. The metabolism of 11αOHP4 and 11βOHP4 was subsequently assayed in several whole cell models in which these novel intermediates were detected as well as quantifiable levels of C11-oxy C19 steroids in the conversion of 11βOHP4. In conclusion, in vitro metabolism by SRD5A, indicates that 11αOHP4 is metabolised in the C11-oxy backdoor pathway with conversion by CYP17A1 yielding 11α-hydroxylated C19 steroids. Data suggest that 11αOHP4 may add to active C11-oxy C19 steroids with the 11α-intermediates attenuating the inhibitory potential of the steroids leading to the production of 11KDHT. However, the conversion of 11αOHP4 by SRD5A and CYP17A1 is less efficient than that of 11βOHP4—indicating that the contribution of 11αOHP4 to the active androgen pool would be markedly lower, suggesting a potential mechanism controlling the flux towards active C11-oxy androgens. Although the contribution to the androgenic pool remains unclear, the role of 11αOHP4 is more complex than that of one being labelled just as an inhibitor of 11βHSD2.

Unravelling drug-induced hypertension: molecular mechanisms of aldosterone-independent mineralocorticoid receptor activation by posaconazole.

ABSTRACTDrug-induced hypertension offers the opportunity to further understand pathways involved in the regulation of blood pressure. Posaconazole is an antifungal agent known to induce hypertension and hypokalaemia. In recent months, a flurry of reports has unravelled the metabolic processes involved. In this issue of CKJ, Barton K, Davis TK, Marshall B et al. Posaconazole-induced hypertension and hypokalemia due to inhibition of the 11β-hydroxylase enzyme. Clin Kidney J 2018; 11: 691–693 present convincing evidence of 11β-hydroxylase inhibition resulting in a biochemical syndrome resembling genetic congenital adrenal hyperplasia and characterized by high 11-deoxycorticosterone and 11-deoxycortisol levels as well as androgen levels. This adds to prior evidence supporting inhibition of 11β-hydroxysteroid dehydrogenase 2, the enzyme that inactivates cortisol in aldosterone-sensitive tissues such as the kidneys, yielding a syndrome resembling genetic apparent mineralocorticoid excess or licorice toxicity, characterized by a high cortisol/cortisone ratio.

Inhibition of 11β-hydroxysteroid dehydrogenase 2 by the fungicides itraconazole and posaconazole

Impaired 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)-dependent cortisol inactivation can lead to electrolyte dysbalance, hypertension and cardiometabolic disease. Furthermore, placental 11β-HSD2 essentially protects the fetus from high maternal glucocorticoid levels, and its impaired function has been associated with altered fetal growth and a higher risk for cardio-metabolic diseases in later life. Despite its important role, 11β-HSD2 is not included in current off-target screening approaches. To identify potential 11β-HSD inhibitors among approved drugs, a pharmacophore model was used for virtual screening, followed by biological assessment of selected hits. This led to the identification of several azole fungicides as 11β-HSD inhibitors, showing a significant structure-activity relationship between azole scaffold size, 11β-HSD enzyme selectivity and inhibitory potency. A hydrophobic linker connecting the azole ring to the other, more polar end of the molecule was observed to be favorable for 11β-HSD2 inhibition and selectivity over 11β-HSD1. The most potent 11β-HSD2 inhibition, using cell lysates expressing recombinant human 11β-HSD2, was obtained for itraconazole (IC50 139±14nM), its active metabolite hydroxyitraconazole (IC50 223±31nM) and posaconazole (IC50 460±98nM). Interestingly, experiments with mouse and rat kidney homogenates showed considerably lower inhibitory activity of these compounds towards 11β-HSD2, indicating important species-specific differences. Thus, 11β-HSD2 inhibition by these compounds is likely to be overlooked in preclinical rodent studies. Inhibition of placental 11β-HSD2 by these compounds, in addition to the known inhibition of cytochrome P450 enzymes and P-glycoprotein efflux transport, might contribute to elevated local cortisol levels, thereby affecting fetal programming.

Inhibition of 11β-hydroxysteroid dehydrogenase 2 by the fungicides itraconazole and posaconazole

Inhibition of 11β-hydroxysteroid dehydrogenase 2 by the fungicides itraconazole and posaconazole

Pistacia lentiscus Oleoresin: Virtual Screening and Identification of Masticadienonic and Isomasticadienonic Acids as Inhibitors of 11β-Hydroxysteroid Dehydrogenase 1.

In traditional medicine, the oleoresinous gum of Pistacia lentiscus var. chia, so-called mastic gum, has been used to treat multiple conditions such as coughs, sore throats, eczema, dyslipidemia, and diabetes. Mastic gum is rich in triterpenes, which have been postulated to exert antidiabetic effects and improve lipid metabolism. In fact, there is evidence of oleanonic acid, a constituent of mastic gum, acting as a peroxisome proliferator-activated receptor γ agonist, and mastic gum being antidiabetic in mice in vivo. Despite these findings, the exact antidiabetic mechanism of mastic gum remains unknown. Glucocorticoids play a key role in regulating glucose and fatty acid metabolism, and inhibition of 11β-hydroxysteroid dehydrogenase 1 that converts inactive cortisone to active cortisol has been proposed as a promising approach to combat metabolic disturbances including diabetes. In this study, a pharmacophore-based virtual screening was applied to filter a natural product database for possible 11β-hydroxysteroid dehydrogenase 1 inhibitors. The hit list analysis was especially focused on the triterpenoids present in Pistacia species. Multiple triterpenoids, such as masticadienonic acid and isomasticadienonic acid, main constituents of mastic gum, were identified. Indeed, masticadienonic acid and isomasticadienonic acid selectively inhibited 11β-hydroxysteroid dehydrogenase 1 over 11β-hydroxysteroid dehydrogenase 2 at low micromolar concentrations. These findings suggest that inhibition of 11β-hydroxysteroid dehydrogenase 1 contributes to the antidiabetic activity of mastic gum.

Glycyrrhizic Acid as the Modulator of 11β -hydroxysteroid dehydrogenase (Type 1 and 2) in Rats under Different Physiological Conditions in Relation to the Metabolic Syndrome

Worldwide increase in the prevalence of metabolic syndrome has raised great attention to this disorder. Despite the effectiveness of the currently available therapeutic agents, most of the drugs elicit harmful side effects. Glycyrrhizic acid (GA) found in the licorice shrub, Glycyrrhiza glabra has been shown to exert anti-hyperglycaemic and antidyslipidaemic effects on rats under different physiological conditions via various mechanisms. The main route being the non-selective inhibition of 11β-hydroxysteroid dehydrogenase, an enzyme catalyzing the inter-conversion of active and inactive glucocorticoids. Altered intracellular glucocorticoid metabolism shows a stronger correlation to the development of metabolic syndrome compared to circulating glucocorticoid. Hence, this review focus on the role of GA in modulating glucocorticoid production in different tissues via regulation of 11β- hydroxysteroid dehydrogenase (both type 1 and 2) activities under different physiological conditions.

Antisense reduction of 11β-hydroxysteroid dehydrogenase type 1 enhances energy expenditure and insulin sensitivity independent of food intake in C57BL/6J mice on a Western-type diet

We recently reported that inhibition of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) by antisense oligonucleotide (ASO) improved hepatic lipid metabolism independent of food intake. In that study, 11β-HSD1 ASO-treated mice lost weight compared with food-matched control ASO-treated mice, suggesting treatment-mediated increased energy expenditure. We have now examined the effects of 11β-HSD1 ASO treatment on adipose tissue metabolism, insulin sensitivity, and whole-body energy expenditure. We used an ASO to knock down 11β-HSD1 in C57BL/6J mice consuming a Western-type diet (WTD). The 11β-HSD1 ASO-treated mice consumed less food, so food-matched control ASO-treated mice were also evaluated. We characterized body composition, gene expression of individual adipose depots, and measures of energy metabolism. We also investigated glucose/insulin tolerance as well as acute insulin signaling in several tissues. Knockdown of 11β-HSD1 protected against WTD-induced obesity by reducing epididymal, mesenteric, and subcutaneous white adipose tissue while activating thermogenesis in brown adipose tissue. The latter was confirmed by demonstrating increased energy expenditure in 11β-HSD1 ASO-treated mice. The 11β-HSD1 ASO treatment also protected against WTD-induced glucose intolerance and insulin resistance; this protection was associated with smaller cells and fewer macrophages in epididymal white adipose tissue as well as enhanced in vivo insulin signaling. Our results indicate that ASO-mediated inhibition of 11β-HSD1 can protect against several WTD-induced metabolic abnormalities. These effects are, at least in part, mediated by increases in the oxidative capacity of brown adipose tissue.

11β-Hydroxysteroid dehydrogenase 1 inhibiting constituents from Eriobotrya japonica revealed by bioactivity-guided isolation and computational approaches

The inhibition of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), which catalyzes the conversion of inactive 11-ketoglucocorticoids to active 11β-hydroxyglucocorticoids, emerged as promising strategy to treat symptoms of the metabolic syndrome, including obesity and type 2 diabetes. In this study the leaves of the anti-diabetic medicinal plant loquat (Eriobotrya japonica) were phytochemically investigated following hints from a pharmacophore-based virtual screening and a bioactivity-guided approach. Determination of the 11β-HSD1 and 11β-HSD2 inhibitory activities in cell lysates revealed triterpenes from the ursane type as selective, low micro-molar inhibitors of 11β-HSD1, that is, corosolic acid (1), 3-epicorosolic acid methyl ester (4), 2-α hydroxy-3-oxo urs-12-en-28-oic acid (6), tormentic acid methyl ester (8), and ursolic acid (9). Importantly, a mixture of loquat constituents with moderate activities displayed a pronounced additive effect. By means of molecular modeling studies and the identification of the 11β-HSD1-inhibiting 11-keto-ursolic acid (17) and 3-acetyl-11-keto-ursolic acid (18) a structure–activity relationship was deduced for this group of pentacyclic triterpenes. The mechanism of action elucidated in the present work together with the previously determined pharmacological activities provides these natural products with an astonishing multi-targeted anti-diabetic profile.

Selective inhibition of 11β-hydroxysteroid dehydrogenase 1 by 18α-glycyrrhetinic acid but not 18β-glycyrrhetinic acid

Elevated cortisol concentrations have been associated with metabolic diseases such as diabetes type 2 and obesity. 11β-hydroxysteroid dehydrogenase (11β-HSD) type 1, catalyzing the conversion of inactive 11-ketoglucocorticoids into their active 11β-hydroxy forms, plays an important role in the regulation of cortisol levels within specific tissues. The selective inhibition of 11β-HSD1 is currently considered as promising therapeutic strategy for the treatment of metabolic diseases. In recent years, natural compound-derived drug design has gained considerable interest. 18β-glycyrrhetinic acid (GA), a metabolite of the natural product glycyrrhizin, is not selective and inhibits both 11β-HSD1 and 11β-HSD2. Here, we compare the biological activity of 18β-GA and its diastereomer 18α-GA against the two enzymes in lysates of transfected HEK-293 cells and show that 18α-GA selectively inhibits 11β-HSD1 but not 11β-HSD2. This is in contrast to 18β-GA, which preferentially inhibits 11β-HSD2. Using a pharmacophore model based on the crystal structure of the GA-derivative carbenoxolone in complex with human 11β-HSD1, we provide an explanation for the differences in the activities of 18α-GA and 18β-GA. This model will be used to design novel selective derivatives of GA.

Antisense inhibition of 11βhydroxysteroid dehydrogenase type 1 improves diabetes in a novel cortisone-induced diabetic KK mouse model

The inhibition of 11βhydroxysteroid dehydrogenase 1 (11βHSD1), an enzyme that catalyzes the conversion of inactive cortisone to active cortisol, is an attractive target to treat diabetes by suppressing hepatic gluconeogenesis. To test this hypothesis, we developed a novel glucocorticoid-induced diabetic KK mouse model and used 11βHSD1 antisense oligonucleotide (ASO) as an inhibitory tool. KK mice were treated with 25 or 50 mg/kg/day of 11βHSD1 ASO for 28 days. On day 25, cortisone pellets were surgically implanted to induce diabetes. In the ASO-treated mice, plasma blood glucose levels were significantly reduced by up to 54%. In parallel, cortisol and other diabetes endpoints were also significantly reduced. Hepatic 11βHSD1 mRNA was suppressed by up to 84% with a concomitant respective decrease of up to 49% in the expression of PEPCK. The results suggest that inhibition of 11βHSD1 activity reduces the availability of cortisol to activate the glucocorticoid receptor, down regulates gluconeogenesis and thus reduces plasma glucose levels in cortisone-induced diabetic KK mice.

Estradiol induced inhibition of 11β-hydroxysteroid dehydrogenase 1: an explanation for the postmenopausal hormone replacement therapy effects

The adverse and beneficial effects of postmenopausal hormone replacement therapy include: ischemic heart disease, stroke, pulmonary embolism, breast cancer, an increased rate of onset of asthma as well as reductions in the incidence of diabetes in women with known coronary artery disease and osteoporotic fractures. These varied effects can be explained by the down regulation of 11beta-hydroxysteroid dehydrogenase by estradiol, which results in a reduction of tissue specific cortisol production. The reduction in local cortisol production which diminishes the endogenous anti-inflammatory effects, also allows for the progression of both vascular and pulmonary inflammation. The decrease in cortisol activation reduces insulin resistance and anti-proliferative effects thereby reducing the potential for diabetes but allowing for the emergence of malignancy. Furthermore, the decreased local tissue availability of cortisol reduces the tendency for the development of osteoporosis. New techniques and drugs are being developed to evaluate the modulation of 11beta-HSD1 activity. Further study should result in new ways to control both inflammation and metabolism.

Inhibition of 11β-hydroxysteroid dehydrogenase type 2 by dithiocarbamates

Dithiocarbamates (DTCs), important therapeutic and industrial chemicals released in high quantities into the environment, exhibit complex chemical and biological activities. Here, we demonstrate an effect of DTCs on glucocorticoid action due to inhibition of 11β-hydroxysteroid dehydrogenase (11β-HSD) type 2, converting cortisol to cortisone in the kidney, but not 11β-HSD1, catalyzing the reverse reaction in liver and adipose tissue. Thus, DTCs may locally increase active glucocorticoid concentrations. Preincubation with the DTC thiram abolished 11β-HSD2 activity, suggesting irreversible enzyme inhibition. The sulfhydryl protecting reagent dithiothreitol blocked thiram-induced inhibition and NAD + partially protected 11β-HSD2 activity, indicating that DTCs act at the cofactor-binding site. A 3D-model of 11β-HSD2 identified Cys 90 in the NAD +-binding site as a likely target of DTCs, which was supported by a 99% reduced activity of mutant Cys 90 to serine. The interference of DTCs with glucocorticoid-mediated responses suggests a cautious approach in the use of DTCs in therapeutic applications and in exposure to sources of DTCs such as cosmetics and agricultural products by pregnant women and others.

Environmental inhibition of 11β-hydroxysteroid dehydrogenase

Gossypol, a polyphenolic compound from cotton seed, caused hypokalemia in some men receiving it in a trial of its contraceptive activity. Searching for the mechanism for its hypokalemic action led to the observation that it inhibited 11β-hydroxysteroid dehydrogenase. This would enhance mineralocorticoid effect in the kidney. Many other polyphenols also inhibit this enzyme including those in grapefruit juice. Ingesting 1–2 l of grapefruit juice inhibited this enzyme in two men in a clinical experiment. Tea polyphenols inhibit this enzyme and add to the inhibition caused by gossypol. Men in China have lower serum potassium values than men elsewhere and this is due to the environment, presumably the diet, in China. The importance of dietary and other exogenous inhibitors of this enzyme in electrolyte metabolism remains to be determined.

Inhibition of 11β-hydroxysteroid dehydrogenase by bioflavonoids and their interaction with furosemide and gossypol

Inhibition of 11β-hydroxysteroid dehydrogenase (11β-OHSD) can cause a mineralocorticoid effect. This enzyme, in guinea pig renal cortex microsomes in vitro, is inhibited by quercetin, tea polyphenols, furosemide, and gossypol. The dietary polyphenols, quercetin and tea polyphenols, interact with furosemide to enhance its 11β-OHSD inhibitory effect. Tea polyphenols added to the effect of gossypol. We conclude that the diet contains inhibitors of 11β-OHSD that can alter the activity of this enzyme and may modify the degree of endogenous mineralocorticoid activity.

Structure and function of steroid dehydrogenases involved in hypertension, fertility, and cancer

Short-chain dehydrogenase reductase (SDR) enzymes influence mammalian reproduction, hypertension, neoplasia, and digestion. The three-dimensional structures of two members of the SDR family reveal the position of the conserved catalytic triad, a possible mechanism of keto-hydroxyl interconversion, the molecular mechanism of inhibition, and the basis for selectivity. Glycyrrhizic acid, the active ingredient in licorice, and its metabolite carbenoxolone are potent inhibitors of bacterial 3α,20β-hydroxysteroid dehydrogenase (3α,20β-HSD). The three-dimensional structure of the 3α,20β-HSD carbenoxolone complex unequivocally verifies the postulated active site of the enzyme, shows that inhibition is a result of direct competition with the substrate for binding, and provides a plausible model for the mechanism of inhibition of 11β-hydroxysteroid dehydrogenase and 15-hydroxyprostaglandin dehydrogenase by carbenoxolone. The structure of human 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD) suggests the details of binding of estrone and 17β-estradiol in the active site of the enzyme and the possible roles of various amino acids in the catalytic cleft. The SDR family includes over 50 proteins from human, mammalian, insect, and bacterial sources. Only five residues are conserved in all members of the family, including the YXXXK sequence. X-ray crystal structures of five members of the family have been completed. When the α-carbon backbone of the cofactor binding domains of the five structures are superimposed, the conserved residues are at the core of the structure and in the cofactor binding domain, but not in the substrate binding pocket.

Inhibition of 11-beta-hydroxysteroid dehydrogenase in pregnant rats and the programming of blood pressure in the offspring.

Recent epidemiological studies have linked low birth weight with the later occurrence of cardiovascular and metabolic disorders, particularly hypertension. We have proposed that fetal exposure to excess maternal glucocorticoids may underpin this association. Normally, the fetus is protected from maternal glucocorticoids by placental 11beta-hydroxysteroid dehydrogenase (11beta-HSD). We have previously shown that treatment of pregnant rats with dexamethasone, a synthetic glucocorticoid that is poorly metabolized by the enzyme, reduces birth weight and produces elevated blood pressure in the adult offspring. Moreover, low activity of placental 11beta-HSD correlates with low birth weight in rats. Here, we show that maternal administration of carbenoxolone, a potent inhibitor of 11 beta-HSD, throughout pregnancy leads to reduced birth weight (mean 20 percent decrease) and elevated blood pressures (increase in mean arterial pressure, 9 mm Hg in males, 7 mm Hg in females) in the adult offspring of carbenoxolone-treated rats. This effect requires the presence of maternal adrenal products, as carbenoxolone given to adrenalectomized pregnant rats had no effect on birth weight or blood pressure. These data support the hypothesis that excess exposure of the fetoplacental unit to maternal glucocorticoids reduces birth weight and programs subsequent hypertension and indicate a key role for placental 11beta-HSD in controlling such exposure.

Inhibition of 11β-hydroxysteroid dehydrogenase obtained from guinea pig kidney by furoemide, naringenin and some other compounds

Inhibition of 11β-hydroxysteroid dehydrogenase (11β-OHSD) can cause excess mineralocorticoid effects and hypokalemia. Several substances causing hypokalemia (glycyrrhizic acid in licorice and gossypol) inhibit this enzyme. We tested other compounds for activity to inhibit 11β-OHSD in guines pig kidney cortex microsomes with NADP a cofactor and cortisol as substrate. Furosemide was an inhibitor while bumetanide was not, indicating a mechanism for the increased K + excretion caused by furosemide compared with bumetanide. Naringenin (found in grapefruit juice), ethacrynic acid, and chenodeoxycholic acid had inhibitor IC 50 values similar to glycyrrhizic acid. We conclude that various compounds can inhibit this enzyme and may play a role in K + metabolism and adrenocorticosteroid action.