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

Agar gel electrophoresis and ultracentrifugation on continuous sucrose gradients revealed the presence of a 4S estradiol 'receptor' in cytosols of samples of human benign hyperplastic prostate tissue. High affinity (charcoal stability) and saturability (disappearance with excess competitor) binding characteristics of the molecular species concerned facilitated its clear distinction from similarly migrating serum albumin-steroid complexes. Our data, obtained with human serum, purified human albumin and albumin-enriched cytosol strongly suggest that agar gel electrophoresis, when used alone, may lack specificity for the quantification of estrogen 'receptors'. Radioligand binding to these molecules may be obscured by similarly migrating albumin-steroid complexes which fail to dissociate during electrophoresis. We advocate the inclusion of competitor experiments to improve the specificity of the method.
Steroids 1975 Oct
PMID:Steroid receptors in the human prostate. 1. Estradiol - 17beta binding in benign prostatic hypertrophy. 5 11

The preparation of pure oestradiol-17beta-3-hemisuccinyl-bovine serum albumin conjugate is described. Contrary to previous findings this antigen raised reasonably specific antisera in rabbits which possessed a cross reaction of only 2.0% with oestrone, and 0.8% with oestriol. The production of this specific antisera is considered to be due to the high purity of the antigen. The role of the C-3 phenolic hemisuccinyl linkage of the antigen in raising this specific antisera is discussed.
Steroids 1976 Jun
PMID:The specificity of antisera raised by oestradiol-17beta-3-hemisuccinyl-bovine serum albumin. 5 68

The C-11 (O-carboxymethyl) oxime derivative of 5-alphadihydrotestosterone (5alphaDHT) has been prepared. Due to steric hindrance at C-11, a novel two step procedure was used to introduce the (O-carboxymethyl) oxime at this position. Condensation of this oxime to bovine serum albumin afforded a conjugate which produced anti-5alphaDHT sera inoculated rabbits. Apart from a 30% cross reaction with testosterone, the antisera was reasonably specific for 5alphaDHT.
Steroids 1977 Apr
PMID:Preparation and antigenic properties of 5alpha-dihydrotestosterone-11-(O-carboxymethyl) oxime-BSA conjugate. 6 57

Derivatives of estrone were prepared and linked to bovine serum albumin or its methyl-esterified form to produce immunogens which were effective in raising antisera to estrone sulfate. The most effective was estrone-3-methylphosphonothioate, electrostatically complexed with methylated bovine serum albumin. The ionically combined hapten functioned as an antigenic determinant as do covalently bound haptens when administered to sheep in emulsions with Freund's complete adjuvant. Estrone-3-phosphate covalently or electrostatically linked to bovine serum albumin also produced antisera reactive to estrone sulfate. Estrone sulfate itself, after electrostatically complexing to methylated bovine serum albumin and administration with Freund's complete adjuvant to sheep, was ineffective in producing antisera. The sera which had workable titres to estrone sulfate showed considerable cross-reaction with free estrone but was otherwise highly specific with little or no reaction with other steroid sulfates, glucosiduronates or other free steroids. Radioimmunoassay curves using [6,7-3H]-estrone sulfate were highly sensitive and were effective in the range of 5-250 pg estrone sulfate.
Steroids 1979 May
PMID:Antisera reactive directly to estrone sulfate. 8 81

We report the equilibrium binding parameters for the interactions of the estrogen analogue diethylstilbestrol (DES) with highly purified rat alpha 1-fetoprotein (AFP) and serum albumin preparations. At 25 degrees C and pH 7.4, an association constant (Ka) of about 1.5 X 10(6)M-1 and 2 sites/mole are measured with the DES-AFP system, whereas for the DES-albumin interaction, we find a Ka of approximately 2 X 10(5)M-1 and about 11 sites/mole of protein. The removal of fatty acids from pure AFP causes a reversible 3 fold increase of the number of DES binding sites; the same delipidation procedure applied to albumin slightly diminishes its DES binding parameters. We also demonstrate the capability of DES to displace competitively estradiol-17 beta (E2) from its high affinity sites on the estrophilic rat AFP. Finally, the binding behaviour of the two serum proteins towards the synthetic estrogen is compared to their interaction with the natural hormones. The physiological and pharmacological relevance of these data is discussed.
Steroids 1979 Dec
PMID:Ligand properties of diethylstilbestrol: studies with purified native and fatty acid-free rat alpha 1-fetoprotein and albumin. 9 92

A simple and reliable radioimmunoassay for plasma 3beta, 16alpha-dihydroxy-5-androsten-17-one(16alpha-OH-DHEA) and its sulfate has been developed. The antiserum against 16alpha-OH-DHEA and its sulfate (16alpha-OH-DHEA-3-sulfate) was produced in rabbits immunized with 16alpha-OH-DHEA-3-succinate-bovine serum albumin. This antiserum reacted well with both 16alpha-OH-DHEA and its sulfate and only slightly cross reacted with DHEA and its sulfate. The coefficient of variation (C.V.) of the intra assay was 10.26% for 16alpha-OH-DHEA and 12.32% for 16alpha-OH-DHEA-S. The C.V. of the interassay were 14.34% for 16alpha-OH-DHEA and 15.64% for 16alpha-OH-DHEA-S. The umbilical artery concentrations for 16alpha-OH-DHEA and 16alpha-OH-DHEA-S were 7.20 +/- 6.71 ng/ml and 4490 +/- 2140 ng/ml, and the umbilical vein concentrations were 14.20 +/- 11.27 ng/ml and 2970 +/- 1450 ng/ml respectively.
Steroids 1976 Jun
PMID:Radioimmunoassay of 16alpha-hydroxy-dehydroepiandrosterone and its sulfate. 13 76

Antiserum for radioimmunoassay (RIA) of dehydroepiandrosterone (DHA) was raised in rabbits with the conjugate obtained by coupling 15beta-carboxyethylmercapto-dehydroepiandrosterone with bovine serum albumin. The antiserum proved to have high affinity and specificity for DHA and showed only minor cross-reaction to androst-5-ene-3beta, 17beta-diol (3.5%). The Rivanol-treated antiserum was covalently coupled to Enzacryl Polyacetal to evaluate its utility in solid-phase RIA.
Steroids 1976 Jul
PMID:Synthesis of new steroid haptens for radioimmunoassay. Part II. 15beta-Carboxyethylmercaptodehydroepiandrosterone bovine serum albumin conjugate. Specific antiserum for solid-phase radioimmunoassay of dehydroepiandrosterone. 13 72

A radioimmunoassay for plasma 3 beta, 7 alpha-dihydroxy-5-androsten-17-one (7 alpha-hydroxy DHA) has been developed using anti-sera raised against 3 beta, 7 alpha-dihydroxy-5-androstene-17 beta-carboxyl-bovine serum albumin conjugate and [1, 2 (n) - 3H] 7 alpha-hydroxy DHA as the radioligand. Significant cross reactivity was found with 3 beta, 7 alpha-dihydroxy-5-pregnen-20-one (44%), 3 beta, 7 beta-dihydroxy-5-androsten-17-one (6%), 3 beta, 6 beta-dihydroxy-4-androsten-17-one (2.5%), 3 beta-hydroxy-5-androsten-17-one (DHA, 2%), 3 beta, 7 beta-dihydroxy-5-pregnen-20-one (2%) and 7 alpha-hydroxy-4-androstene-3, 20-dione (1%). 7 alpha-Hydroxy DHA was extracted from plasma and separated from cross-reacting factors using alumina micro-columns. The separation of bound and free steroid was achieved using dextran-coated charcoal. The concentration of 7 alpha-hydroxy DHA in the plasma of breast cancer patients was significantly lower than the concentrations in the plasma of normal women, hospitalized women suffering from non-endocrine diseases and patients with benign breast disease. The decrease in the concentration of 7 alpha-hydroxy DHA in the plasma of pregnant women was not significant.
Steroids 1977 Sep
PMID:A radioimmunoassay for 7 alpha-hydroxy dehydroepiandrosterone in human plasma. 14 70

A radioimmunoassay for corticosterone was developed using an antibody to corticosterone-21-hemisuccinate:bovine serum albumin. The assay possessed good specificity, sensitivity and reproducibility and required minimal sample preparation. Tests of adrenal function showed that stimulation of the adrenal with exogenous ACTH and with dexamethasone caused an increase and decrease, respectively, in plasma concentrations of corticosterone. Exposure to cold environmental temperatures caused an increase in plasma corticosterone. Handling and the removal of blood samples by venepuncture had no effect upon the concentration of corticosterone. It was concluded that this assay would accurately measure the response to stresses which affect the pituitary-adrenal axis.
Steroids 1976 Dec
PMID:A radioimmunoassay for corticosterone and its application to the measurement of stress in poultry. 18 65


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