Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Delta5-3beta HSDH activity has been assayed either by spectrophotometric method or by use of radioactive substrates. The enzymatic activity is equally distributed between mitochondrial and microsomal fractions verified by electronic microscopy. The specific activity is comparable in both fractions, as well as the optimal pH and the Km for NAD and for the substrates. The delta5-3beta Hut optimal pH, specific activity and sensitivity to the inhibitory action of various steroids are different when C19 and C21 steroids are used as substrates. Estrogens and cyclic AMP have also an inhibitory action on the oxidation of C21 steroids. Treatment of microsomal or mitochondrial membranes with phospholipase A releases fatty acids (mainly arachidonic) and decreases the enzymatic activity. "Adsorbtion" of the fatty acids on bovine serum albumin partially reactivates the delta5-3beta HSDH.
Steroids 1975 Nov
PMID:Human placental delta5-3beta hydroxysteroid dehydrogenase activity (delta5-3beta HSDH): intracellular distribution, kinetic properties, retroinhibition and influence of membrane delipidation. 0 79

The proportion of 20 alpha/20 beta-epimers of the urinary C21-steroid metabolites was estimated in normal volunteers and in patients with congenital adrenal hyperplasia (CAH), postpubertal virilizing syndrome (PVS) and polycystic ovary syndrome (POS). In the normal individuals 20 alpha- and 20 beta-epimers of 5 beta-pregnane-3 alpha, 17 alpha, 20-triol (pregnanetriol) and 5-pregnene-3 beta, 17 alpha, 20-triol (5-pregnenetriol) were measured. In the other case 20 alpha- and 20 beta-epimers of the characteristic, representative metabolites were also investigated. In 26 of 27 normal persons and in all the patients with normotensive CAH, PVS and POS the 20 beta-epimer comprised 0-10% of the total pregnanetriol. The 20 beta-epimer of 5-pregnenetriol was found in only one normal case (6% of the total). The percentage of 20 beta-epimers of 3 alpha, 17 alpha, 20-trihydroxy-5 beta-pregnan-11-one, 5 beta-pregnane-3 alpha, 11 beta, 17 alpha, 20-tetrol (in the normotensive CAH, PVS and POS) and 5 alpha- or 5 beta-pregnane-3 alpha, 17 alpha, 20, 21-tetrol (in the hypertensive CAH) varied from nil to 76%. The effect of functional groups and the stereochemistry of the molecule on the direction of C-20-keto group reduction is discussed; the existence of additional factors determining this reduction in certain pathological conditions is suggested.
Steroids 1979 Jan
PMID:Isolation of urinary C-20 alpha- and C-20 beta-hydroxy-C21-steroid metabolites in cases of congenital adrenal hyperplasia, postpubertal virilizing syndrome and polycystic ovary syndrome. 22 14

A group of moderately polar C21 steroids (3-5 oxygen functions) has been chromatographed in 9 solvent systems. Using the concept that standard deviation of the mean RF is an index of chromatographic resolution, and that coefficients of correlation between sets of RF data can be used to quantify the similarities of chromatographic systems, we have evaluated the resolving properties of the systems when used individually, and also when used in combinations of two, three and four. The discriminating powers of some of the most effective individual systems, and some of the sequences of systems which are most efficient, are shown graphically as chromatography trees. The relationship between the total effective standard deviation of a group of systems which are used in sequence and the probability that a pair of compounds will be separated by more than 0.10 RF is discussed.
Steroids 1979 Aug
PMID:An evaluation of systems for paper chromatography of C21 steroids. 49 64

Antisera were obtained from rabbits immunised against cortisol-3-BSA with a view to examining their application in a radioimmunoassay of the steroid. One such antiserum was studied in detail; cross-reactivity with other C21 steroids normally present in human plasma was negligible and it proved possible to establish a radioimmunoassay which satisfied all criteria of reliability. The specificity of the cortisol determination achieved in human plasma was examined by performing measurements with and without including an initial Sephadex LH-20 column chromatographic purification step; the values obtained were in excellent agreement both for normal plasma and for that obtained following adrenal stimulation with ACTH.
Steroids 1975 Sep
PMID:Some observations on the determination of cortisol in human plasma by radioimmunoassay using antisera against cortisol-3-BSA. 123 1

Cortisol mouse monoclonal antibodies were produced and characterized. Of the four clones studied, supernatant from one clone (A2), compared with other cortisol monoclonal antibodies, showed minimal cross-reactivity to other C21 steroids and was suitable for the direct determination of cortisol in plasma by enzyme-linked immunosorbent assay using a standard 96-well microtiter plate. The enzyme-linked immunosorbent assay uses the immobilized antigen approach, in which cortisol in plasma samples or standards competes with immobilized steroid for antibody-binding sites. After washing, the cortisol antibody bound to the wells of the microtiter plate is detected with antimouse immunoglobulin conjugated to horseradish peroxidase. Following further washing, o-phenylenediamine substrate is added. The enzyme-linked immunosorbent assay is robust and semiautomated. The mean +/- SD recovery from plasma was 97% +/- 6%. Precision studies on three different plasma pools showed mean coefficients of variation of 7.6% and 8.6% for within- and between-assay variation, respectively. The satisfactory performance criteria allow its use in the routine laboratory.
Steroids 1992 Feb
PMID:Production of a monoclonal antibody to cortisol: application to a direct enzyme-linked immunosorbent assay of plasma. 162 Dec 61

Ten sex steroids were measured in the peripheral serum and ovarian follicular fluid of female pigs with or without cystic ovarian disease. In general, progestin, especially progesterone, accumulated excessively in the fluid contained in cystic compared with normal follicles. Nonluteinized cystic follicles contained up to four times the progesterone concentration found in large normal preovulatory follicles. Levels of this steroid increased with luteinization of cystic follicles to as much as 10 times those found in large preovulatory follicles. In contrast, the concentration of follicular fluid androgens and estrogens in cystic follicles were, at best, barely detectable (5 to 10 pg/ml). These results are indicative of a steroidogenic blockade in the conversion of C21 progestin to C19 androgens and C18 estrogens in the cystic follicles. In spite of an enormous accumulation of follicular progestin and subnormal concentration of androgens and estrogens, circulating levels of these hormones in pigs bearing cystic ovaries were in the normal range for cycling sows. Clearly, the hormonal abnormalities in the cystic follicles are not reflected in the serum profiles of these steroids.
Steroids 1990 Jul
PMID:Sex steroid changes in porcine cystic ovarian disease. 221

One-and two dimensional proton and carbon NMR spectra of the D-homoannulated rearrangement product of triamcinolone (9 alpha-fluoro-11 beta,16 alpha,17 alpha, 21-tetrahydroxy-pregna-1,4-diene-3,20-dione) establish its structure as that of 9 alpha-fluoro-11 beta,16 alpha,17 alpha-trihydroxy-17 beta-hydroxy-methyl-D-homoandrosta-1,4-diene-3,17 alpha-dione. These methods accord ready recognition of D-homoannulation of C21-17-hydroxy-20-ketosteroids.
Steroids
PMID:Recognition of D-homoannulation by proton and carbon NMR spectra. 255 19

Condensation of C22 and C21 steroidal aldehydes with ethyl 4,6-dimethyl-2-oxo-2H-pyran-5-carboxylate 1 in alkaline medium, followed by decarboxylation, provides a simple route to the alpha, beta-unsaturated side-chain delta-lactone synthesis for a classical withanolide precursor.
Steroids 1989 Sep
PMID:A convenient preparation of the side-chain lactone ring of a withanolide precursor. 258 5

After injection into male and female fifth-instar larvae of Manduca sexta, [14C]cholesterol was converted to C21 steroids, [14C]pregn-5-ene-3 beta,20-diols. These metabolites were isolated from 8-day-old pupae and were identified by TLC, HPLC, and GC-MS as the C-20 isomers of pregnene-3 beta,20-diol. They also were isolated from male and female meconium fluid (of 16-day-old pupae) following injection of [14C]cholesterol into 14-day-old pupae.
Steroids
PMID:Metabolism of [14C]cholesterol to C-20 isomeric [14C]pregn-5-ene-3,20-diols in the tobacco hornworm, Manduca sexta. 279 53

3 beta-Hydroxysteroid isomerase dehydrogenase, capable of acting on C21- and C19-3 beta-hydroxy-5-ene-steroids has been found in guinea-pig kidney at equivalent levels to those in guinea pig testes. Of the 3 beta-hydroxy-5-ene-steroids present in guinea pig serum, 21-hydroxypregnenolone occurs in highest concentration (17 nM) followed by pregnenolone (10 nM), whereas 17 alpha-hydroxy-pregnenolone and dehydroepiandrosterone occur in very low concentrations (less than 0.5 nM). Furthermore, the concentration of 21-hydroxypregnenolone relative to 11-deoxycorticosterone (the mineralocorticoid of the guinea pig), is 10:1 (Nishikawa and Strott, Steroids 41 (1983) 105-120). The apparent Km value for 21-hydroxypregnenolone, for the reaction yielding 11-deoxycorticosterone as catalysed by guinea pig kidney microsomes, was 85 nM and the Vmax 33 pmol/min per mg protein. Pregnenolone was a competitive inhibitor (apparent Ki = 5 microM) in the above reaction. A sex difference in the level of the enzyme in the kidney was found (activity in the female was one-third of that in the male) which may indicate that the enzyme is under partial androgen control. 3 beta-Hydroxysteroid isomerase dehydrogenase activity was also detected in guinea pig liver and again it was lower in the female. Whilst the exact role of 3 beta-hydroxysteroid isomerase dehydrogenase in guinea-pig kidney remains uncertain, the data suggest that it may utilise blood-borne 21-hydroxypregnenolone, the later then playing the role of a prohormone.
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PMID:3 beta-hydroxysteroid isomerase dehydrogenase in guinea-pig kidney: possible involvement in 11-deoxycorticosterone formation in situ. 301 75


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