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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An in vitro method for measuring aromatase cytochrome P450 enzyme (P450AROM) in human granulosa cells (GC) has been developed, based on binding of the 11C-labeled aromatase inhibitor vorozole. GC were obtained following superstimulation during in vitro fertilisation. The method revealed a binding affinity (Kd) of 0.4 nM and a maximum binding (Bmax) at 11 fmol/4000 cells which is equal to 1.6 million binding sites per cell. Linear Scatchard plots indicated a single type of binding site. P450AROM concentrations measured by [11C]vorozole binding correlated positively with aromatisation of [1beta-3H]androst-4-ene-3,17-dione measured as [3H]water release, and a positive association was also found with the ovarian in vivo response to follicle-stimulating hormone (FSH) stimulation expressed as 1000 times the ratio of the number of oocytes recovered from a patient and the total dose of recombinant FSH administered. Frozen cells could be used for P450AROM quantitation, provided the correct freezing procedure was used. Quantitation of P450AROM, based on binding of [11C]vorozole is an accurate and sensitive in vitro method, which might be extended to the measurement of aromatase expression by a noninvasive technique in the intact ovary in vivo using positron emission tomography.
Steroids 1999 Apr
PMID:In vitro evaluation of aromatase enzyme in granulosa cells using a [11C]vorozole binding assay. 1039 83

Recent advances in microbial steroid hydroxylation are covered, including new biocatalysts and substrate groups and new methodologies such as the use of low-water systems, immobilised biocatalysts, genetically constructed biocatalysts and enzyme mimics. Mechanistic factors that control the regiochemistry and stereochemistry of steroid hydroxylation are also discussed.
Steroids 1999 Mar
PMID:Recent advances in applied and mechanistic aspects of the enzymatic hydroxylation of steroids by whole-cell biocatalysts. 1040 Mar 78

Ceramide is known to have major roles in the control of cell proliferation, differentiation, and apoptosis. Recent studies also have shown that ceramide affects steroid production by JEG-3 choriocarcinoma cells, acutely dispersed rat Leydig cells, and ovarian granulosa cells, but the mechanism by which this occurs is unknown. Because ceramide induces apoptosis in many different cell types, we hypothesized that ceramide might affect steroidogenesis and/or induce apoptosis in MA-10 murine Leydig cells. To test this, MA-10 cells were incubated with either the water soluble C2-ceramide, (N-acetyl-sphingosine, 0.01-10 cm); bacterial sphingomyelinase (1-100 mU/ml); or C2-dihydroceramide (N-acetyl-sphinganine, 0.1-10 microM). The data show that N-acetyl-sphingosine significantly increased basal (0.87 +/- 0.2 vs. 0.42 +/- 0.09 ng/mg cell protein, P < 0.01) and human chorionic gonadotropin (hCG) stimulated progesterone (P) synthesis (204 +/- 12 vs. 120 +/- 5 ng/mg cell protein, P < 0.001); as did sphingomyelinase (basal P = 0.83 +/- 0.1 ng/mg cell protein, P < 0.01; hCG stimulated P = 173 +/- 7 ng/mg cell protein, P < 0.001). C2-dihydroceramide also increased basal P synthesis but was less effective than ceramide on a molar basis. Neither sphingomyelinase (100 mU/ml) nor ceramide (10 microM) had any effect on cAMP production or human chorionic gonadotropin binding; and neither induced any signs of apoptosis (FragEL DNA fragmentation assay and electron microscopy). Cells incubated with anti-Fas (300 ng/ml) demonstrated DNA fragmentation, nuclear condensation, and frequent apoptotic bodies, but had no change in P synthesis. These data show that ceramide significantly increases MA-10 Leydig cell P synthesis but does not induce apoptosis. The mechanism by which ceramide increases steroid hormone synthesis remains unknown but does not appear to be linked to the induction of apoptosis in MA-10 cells.
Steroids 1999 Aug
PMID:Ceramide increases steroid hormone production in MA-10 Leydig cells. 1049 94

Products of Chicken Embryo (PCE) such as Ji-Pei-Jing is a kind of food for Chinese children prepared from chicken embryo. Female rats on 21 days were administered with aqueous solutions of Ji-Pei-Jing (1.2%, 3%, 12%, and 48%, respectively) by gavage up to their onsets of puberty. The rats in the control group were treated with distilled water. However, Ji-Pei-Jing treatment exerted some effects on sexual maturation in the immature female rats. Essentially, the effects showed a dose-response tendency with an inverted "U" shape. The age of vaginal opening for group treated with Ji-Pei-Jing was significantly earlier than that to the control. Its uterus weight/b.w. ratio also significantly increased on day 30 and at the first estrus. There were significantly increases in the adrenal weight/b.w. ratio of 30-day-old rats that were treated with 3%, 12%, and 48% Ji-Pei-Jing. The rats treated with 48% Ji-Pei-Jing had significantly lesser ovary weight/b.w. ratio on day 30, too. The rats treated with Ji-Pei-Jing could normally ovulate at the first estrus, and no significant differences were observed during estrous cycles. The effects of PCE on serum levels of E2, P, LH in 30-day-old rats and FSH in 28-day-old rats were elevated significantly by 3% Ji-Pei-Jing treatment. It appears that the effects of PCE result from interaction of contained complex physiologically active substances. Steroids, especially estradio-17 beta, possibly play a key role, and polypeptide hormones may also exert important effects.
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PMID:Effects of "products of chicken embryo" on growth and sexual development in rats. 1056 May 38

7-Oxo-dehydroepiandrosterone, which can be formed from dehydroepiandrosterone (DHEA) by several mammalian tissues, is more effective than its parent steroid as an inducer of thermogenic enzymes when administered to rats. Using the Morris water maze procedure, we tested DHEA and its 7-oxo-derivative for their ability to reverse the memory abolition induced by scopolamine in young C57BL/6 mice, and for their effect on memory in old mice. A single dose of 7-oxo-DHEA-acetate at 24 mg/kg b.w. completely reversed the impairment caused by 1 mg of scopolamine per kg b.w. (P < 0.001). DHEA (20 mg/kg) was also effective (P < 0.01). In old mice given the same single doses followed by feeding 0.05% of the respective steroid in the diet, memory of the water maze training was retained through a four week test period in mice receiving 7-oxo-DHEA-acetate (P < 0.05) but not in the control or DHEA-treated groups. When old mice were not tested until five weeks after being trained 7-oxo-DHEA exerted a slight, but statistically insignificant, improvement in memory retention. The possible effect of 7-oxo-DHEA in human memory problems deserves investigation.
Steroids 2000 Mar
PMID:The effect of 7-oxo-DHEA acetate on memory in young and old C57BL/6 mice. 1069 90

The influence of temperature on retention and separation of estrogens, progesterone derivatives and beta-cyclodextrin in reversed-phase high-performance liquid chromatography has been studied. Steroids were detected using direct UV detection at 240 and 280 nm. Detection of beta-cyclodextrin was achieved using a post-column indirect photometric method. Chromatographic experiments were performed using an acetonitrile-water mobile phase (30%, v/v) and a wide range of column temperatures from 0 to 80 degrees C with 20 degrees C steps. Linear Van't Hoff plots were observed for steroids and beta-cyclodextrin when an unmodified binary mobile phase was applied. The retention of steroids was strongly influenced by temperature when the mobile phase was modified with beta-cyclodextrin at a concentration of 12 mM. Particularly, for 17beta-estradiol and 20alpha-hydroxyprogesterone a strong deviation from the linear Van't Hoff plots and a remarkable affinity for beta-cyclodextrin was observed. Polynomial regression calculations were performed to fit the set of experimental data points. Using third-order polynomial equations, minimum separation factor values (alphamin) were calculated for temperatures from -10 to + 100 degrees C with 1 degrees C steps. The best chromatographic conditions for separation of multicomponent samples were chosen. A possible retention mechanism for solutes in the presence of macrocyclic additives is discussed. The results presented describe the role of temperature in high-performance liquid chromatography systems in which the mobile phase is modified with an inclusion agent.
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PMID:Separation of steroids using temperature-dependent inclusion chromatography. 1130 86

The oxidative decomposition of skin lipids by UV exposure and its cell toxicity were studied in vivo and in vitro, using guinea pigs, to investigate the role of oxidative damage in cell membranes and mitochondria in nuclear genome DNA damage resulting in skin cell death by ultraviolet (UV) exposure. Two new methods were developed for this research: selective methylation by trimethylsilyldiazomethane (TMSCHN2) of free fatty acids in crude skin lipids for gas chromatography-mass spectrometry (GC-MS) analysis, and the improvement of the thiobarbituric acid (TBA) reaction for lipid peroxide analysis, which was obtained by adding 0.01% BHT and 1 mM EDTA, an antioxidant additive, into the reaction system described by Ohkawa. The following findings were noted: 1. Using an optical microscope, the infiltration of inflammatory cells such as neutrophils, lymphocytes and monocytes was noted after skin tissue was exposed to UV. 2. The increase of lipid peroxide in exposed areas was small. In the epidermis the increase was about 2 times higher than the non-exposed areas. 3. The fragments of lipid were generated in accordance with the increase of free fatty acids (C16:0, C18:1,:2, C18:0) in the surface of the exposed skin by GC-MS precise assay, and the level of 7-dehydrocholesterol was decreased. 4. The skin homogenate received peroxidation by ultraviolet more easily than living skin, and its peroxidation was inhibited with fat-soluble antioxidative agents such as flavonoids, BHT, BHA, and vitamin E and the metal chelating agent such as Fenton reaction inhibitor as expected; however, it was promoted by water soluble antioxidative agents such as glutathione and vitamin C, which are useful to the human body. 5. Steroids and nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin and aspirin, had no inhibitory effect on lipid peroxidation by ultraviolet as properties of chemicals.
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PMID:[Relationship between changes in skin lipids by ultraviolet exposure and the cell toxicity]. 1151 84

Recent studies have suggested that bile acid acyl glucuronides form covalently bound protein adducts which may cause hypersensitivity reactions and increased morbidity in patients. Although the preferential biosynthesis of the acyl glucuronides has been known, the characterization of hepatic bile acid acyl glucuronosyltransferase has not yet been clearly elucidated. We have investigated the substrate specificity of the hepatic bile acid acyl glucuronosyltransferase using five common bile acids as substrates. The glucuronidation rate was dependent on the number of the hydroxy group on the steroid nucleus and mono-hydroxylated lithocholic acid, the more lipophilic common bile acid, was most effectively metabolized into its acyl glucuronide. The tri-hydroxylated cholic acid, the more water-soluble common bile acid, barely transformed into its glucuronide. Results showed decreasing of the initial velocity of the acyl glucuronidation with increasing of the concentration of substrate, lithocholic acid, owing to the substrate inhibition of the hepatic bile acid acyl glucuronosyltransferase. The substrate analogues, glycine and taurine conjugated bile acids, which exist in the body fluids in high concentrations, also inhibited the enzyme's activity. In addition, enzymatic reaction products, bile acid acyl glucuronides, also inhibited the activity. These inhibitory mechanisms may be responsible for the low concentration of bile acid acyl glucuronides in urine and may be an important detoxification system in the body.
Steroids 2002 Mar
PMID:Characterization of rat liver bile acid acyl glucuronosyltransferase. 1185 49

The crystal structure of cesium cholate, C(24)H(36)(OH)(3) COOCs has been determined with three-dimensional X-ray diffractometer data. It crystallized in the monoclinic space group P2(1) with unit-cell dimensions a = 11.543(5) A, b = 8.614(3) A, and c = 12.662(5) A, beta(deg) = 107.95(2), V = 1197.7 A(3) and Z = 2. The atomic parameters were refined to a final r = 0.0269 and R(omega) = 0.0280 for 2342 observed reflections. Each Cs(+) is coordinated to 7 oxygen atoms from 5 different cholate anions with Cs-O distances ranging from 2.957(4) A to 3.678(5) A. In this crystal, 5 cholates are coordinated with 1 Cs(+), and 5 Cs(+) are coordinated with 1 cholate anion. Carboxyl and all the 3 ring hydroxyl groups of cholate anion participate in binding to Cs(+) simultaneously, and there is no water molecule coordinated with the Cs(+). The pattern of successive rows arranged with polar (p) and non-polar (n) faces in apposition leads to the formation of a sandwich sheet structure with polar and non-polar channels. The Cs ions lie within the polar interior of the sandwich. The H-bond network is reorganized in forming cesium cholate from cholic acid. All the oxygen atoms in cholate anion are involved in H-bonding reciprocally or with water molecules to form an extensive 3-dimensional network of H-bonds. Compared with cholic acid and other similar type of steroids, the coordination structure and H-bonding of Cs cholate crystal are distinct.
Steroids 2002 Apr
PMID:Cesium cholate: determination of X-ray crystal structure indicates participation of the ring hydroxyl groups in metal binding. 1195 95

Steroids administrated antenatally to the mothers improve postnatal outcomes of the newborns with pleiotropic effects. Furthermore steroids have been used in preterm infants to prevent or treat chronic lung disease. Synthetical glucocorticoids readily cross placental barrier and reach significant pharmacologic levels in the fetus: besides their well known pulmonary effects they have a concomitant maturational effect of postnatal renal function in preterm infants both with a direct and indirect effect. Endogenous and exogenous glucocorticoids play a role in the maintenance of glomerular filtration (GFR). The antenatal administration of steroids increases the GFR, in association to the maturation of the tubular function. According to different studies the improvement of renal function, expressed by the increase of GFR, is only partially referable to the increase of MAP and the improvement of the cardiovascular status, while it was imputable to a direct renal effect of the steroids, especially on the renal blood flow, on functional glomerular surface area available for filtration and on the glomerular filtrate of the single cortical nephron. However debate remains about the mechanism through which steroids would act on the renal vascular smooth muscolature. The increase the GFR observed after the antenatal administration of glucocorticoids in premature fetuses is also accompanied by an increase of urinary flow and of fractional excretion of sodium. Glucocorticoids would increase the proximal reabsorption of sodium increasing directly the function and the expression of the sodium transporters and both indirectly and directly increasing the activity of Na-K-ATPase. In extremely low weight antenatal administration of betamethasone or dexamethasone was associated with lower estimated insensible water loss, secondary to a direct maturational effect in the skin epithelial barrier, as well as an increased reabsorption of the fetal lung fluid. Moreover antenatal glucocorticoid administration was associated, at birth, to a significant suppression of plasma renin activity and angiotensin II in comparison to the controls. Despite the wide use of the steroidal therapy in the prevention of the bronchopulmonary dysplasia, only few articles, in literature, analyse the effects of glucocorticoids on postnatal renal function, such as the increase in urinary flow. The authors think that steroids contribute in a meaningful way to the clinical improvement observed in children with BPD through the maturative action on the premature kidney with effect both at glomerular and tubular level.
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PMID:Renal effects of antenatally or postnatally administered steroids. 1198 24


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