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

Epithelial cells derived from duct epithelium were cultured from early lactation human milk in medium supplemented with 15% fetal calf serum, insulin (0.3 u/ml), cortisol 21-sodium succinate (6 micrograms/ml) and amikacin (50 micrograms/ml). The capacity of these cells to metabolize androstenedione to estrone, estradiol and C19 metabolites was studied during continuous culture. After extraction of the medium, the products were subjected to phenolic partition and separated by thin-layer and paper chromatography, followed by recrystallization to constant specific activity. The study demonstrated a progressive increase in the formation of estrone and testosterone over the first 24 h in culture, while estradiol formation showed an initial 2-4 h lag, then increased slowly. The C19 compounds identified were androsterone, 5 alpha-androstanedione, epiandrosterone, dihydrotestosterone and etiocholanolone. 5 alpha-Androstanedione and androsterone were the major 5 alpha-reduced metabolites. Since these cells are derived from normal duct epithelium, their metabolic characteristics may be more representative of normal breast tissue than those of tissue removed from patients with pathological breast disorders.
Steroids 1983 Oct
PMID:Androstenedione metabolism in epithelial cells derived from early-lactation human milk. 667 45

A procedure is described for the chemical synthesis of steroidal-20-oxo-21-oic acids and -17 alpha(-hydroxy-20-oxo-21-oic acids. Corticosteroid derivatives containing the 20-oxo-21-aldehyde side chain are oxidized with freshly generated silver oxide in dilute aqueous sodium hydroxide.
Steroids 1983 Nov
PMID:An improved method for the chemical synthesis of steroidal 20-oxo-21-oic acids. 668 Sep 28

A method is presented for the chemical synthesis of corticosteroid derivatives containing the 20 alpha, 21-diol and 17 alpha, 20 alpha, 21-triol side chains. The ketol side chains of cortisol, corticosterone, 11-deoxycortisol, and 11-deoxycorticosterone were reduced at C-20 with sodium borohydride in a two-phase system consisting of aqueous calcium chloride and an organic phase of chloroform or ethyl acetate. Stereoselectivity of reduction was 92% alpha-oriented for cortisol and 79% alpha-oriented for 11-deoxycortisol at -27 degrees. The 20 alpha-form diminished relative to the 20 beta-form with increasing temperature. For the 17-deoxy steroids, reduction to the 20 alpha-form was 23% for 11-deoxycorticosterone and 41% for corticosterone. The 20 alpha/20 beta ratios of 17-deoxy steroids were unchanged between 0 degree and -27 degrees. Calcium ions increased the solubility of corticosteroids in the aqueous phase. We propose that calcium ions affect the stereochemistry of reduction by forming a bidentate complex with the side chains of 17 alpha-hydroxy steroids, fixing them in an orientation favorable to 20 alpha-reduction, and by altering the phase partition of the steroids.
Steroids 1983 Dec
PMID:Asymmetric reduction of steroidal 20-ketones: chemical synthesis of corticosteroid derivatives containing the 20 alpha, 21-diol and 17 alpha, 20 alpha, 21-triol side chains. 668 Sep 32

From rat liver microsomes a NAD: 3 alpha-hydroxy-5 alpha-pregnan-20-one oxidoreductase was isolated and purified up to a specific activity of 73 nmol/min . mg by affinity chromatography and DEAE-cellulose chromatography. Various Km-values have been determined. The enzyme exhibits highest affinity for 5 alpha-pregnane-3,20-dione and NADH. The 3-oxo group of 5 alpha-dihydrocortisone (17,21-dihydroxy-5 alpha-pregnane-3,11,20-trione) was not reduced by the purified enzyme preparation and NADH and no dehydrogenation with NAD was observed of 3 alpha,11 beta,17,21-tetrahydroxy-5 alpha-pregnan-20-one. The optimal pH for the hydrogenation of th 3-oxo group was at pH 5.3 and for the dehydrogenation at pH 8.9. Disc gel electrophoresis in presence of 0.1% sodium dodecylsulfate yielded a homogeneous preparation.
Steroids 1980 Aug
PMID:Purification and properties of a NAD: 3 alpha-hydroxy-5 alpha-pregnan-20-one-oxidoreductase from rat liver microsomes. 693 32

Synthesis, biochemical and biological testing of the first carborane derivatives of estrogens are described. Estrone 3-carboranylmethyl ether was synthesized in two steps from estrone. Reduction of estrone 3-carboranylmethyl ether with sodium borohydride provided estradiol-17 beta 3-carboranylmethyl ether. Enzyme kinetic measurements showed that estrone 3-carboranylmethyl ether is a substrate for human placental 17 beta-hydroxysteroid dehydrogenase with Km = 5 x 10(-6)M, and Vmax = 0.016 mumol min-1 microgram -1. The relative affinity constant of estradiol-17 beta 3-carboranylmethyl ether for rat uterine estrogen receptor was 0.5 (compared with a value of 100 for estradiol-17 beta). Consistent with its low affinity for estrogen receptor, the dose-dependent uterotropic response to estradiol-17 beta 3-carboranylmethyl ether in castrated female rats was one sixtieth that of estradiol-17 beta. None of the tested rats had a toxic reaction to estradiol-17 beta 3-carboranylmethyl ether. These results demonstrate that exceptionally stable carborane derivatives of estrogens can be synthesized with preservation of their biochemical and biological properties. Boron-containing estrogens may be useful for thermal neutron capture therapy of cancers with estrogen receptors to concentrate boron in the cell nucleus.
Steroids 1981 Feb
PMID:Boron estrogens: synthesis, biochemical and biological testing of estrone and estradiol-17 beta 3-carboranylmethyl ethers. 693 60

The mechanism of the uptake of cholic acids and the interaction of various bile acids on the cholic acid uptake were investigated using isolated rat hepatocytes. The uptake consisted of unsaturable and saturable processes at 0 degrees C and 37 degrees C, respectively. The activation energy found for the saturable process was 26.1 Kcal/mol. In the saturable process the rate of cholic acid uptake followed Michaelis-Menten kinetics with Km: 67 microM and Vmax: 1.43 nmoles/ml protein/min. The uptake was significantly inhibited by 2,4-dinitrophenol, and replacement of extracellular Na+ by choline did not decrease the uptake. The uptake of cholic acid was competitively inhibited by deoxycholic acid, taurocholic acid, glycocholic acid, chenodeoxycholic acid, taurochenodeoxycholic acid and glycochenodeoxycholic acid. It is concluded from the above results that the cholic acid uptake in isolated hepatocytes is mainly mediated by an energy-dependent and sodium-independent carrier-mediated transport process.
Steroids 1982 Jan
PMID:Uptake of cholic acid by freshly isolated rat hepatocytes: presence of a common carrier for bile acid transports. 708 Jan 14

Controlled alkaline hydrolysis of 16 alpha-bromo-17-keto steroids 1, 5 and 7 with potassium carbonate and tetra-n-butylammonium hydroxide (n-Bu4NOH) and synthesis of 2 alpha-hydroxy-3-ones 11, 13 and 16 by the controlled hydrolysis of the corresponding 2 alpha-bromo-3-ones 9, 12 and 15 are described. Treatment of the bromoketones 1,5 and 7 with potassium carbonate in aqueous acetone or with n-Bu4NOH in aqueous dimethylformamide (DMF) gave 16 alpha-hydroxy-17-ones 3m 6 and 8 in 85-90% yield, respectively. 2 alpha-Hydroxy-3-ones 11, 13 and 16 were obtained by hydrolysis of the corresponding bromoketones 9, 12 and 15 in high yields using the above conditions or sodium hydroxide in pyridine or DMF, respectively. Deuterium labeling experiments suggested that equilibration between the 2 alpha-bromoketone 9 and the 2 beta-bromo isomer 10 precedes the formation of the ketol 11 in which the true intermediate might be the 2 beta-isomer 10. However, rearranged androstane derivatives, 3 beta-hydroxy-2-one 18 and 20, were stereoselectively obtained by treatment of the bromoketones 12 and 15 with an excess amount of sodium hydroxide.
Steroids 1982 Mar
PMID:Controlled alkaline hydrolysis of steroidal alpha-bromoketones: new conditions and synthesis of 2 alpha-hydroxy-3-ones. 709 29

We studied the effect of sodium thiocyanate (NaSCN) in the determination of specific nuclear estrogen receptors from the hypothalamic-pituitary axis (HPA) of mice. We compared the results with those of the exchange assay using either suspensions of whole nuclei or KC1-nuclear extracts. Our findings demonstrated that 0.5 M NaSCN was more efficient than 0.5 M KC1 in extracting [3H] E2 nuclear content from HPA (91% vs 79.3%). Nuclear fractions extracted with 0.5 M NaSCN revealed the presence of a single class of low-capacity-high affinity binding sites that sedimented in the 4.0 S area. Nuclear binding was T degrees dependent and reached maximum levels of 450 +/- 156 (S.E.) fmol/mg DNA after an overnight incubation at 4 degrees C. Such levels were comparable to those observed in whole nuclei suspensions after 1 hour incubation at 37 degrees C (618 +/- 71 fmol/mg DNA, p greater than 0.05) but two-fold higher (p less than 0.01) than the concentration of binding sites measured in KC1-extracted nuclear fractions under similar experimental conditions. We conclude that NaSCN extracted the total content of nuclear estrogen receptors in HPA of mature mice.
Steroids 1982 Jun
PMID:Exchange assays using sodium thiocyanate to measure total nuclear content of estrogen receptors in the hypothalamic pituitary axis of mice. 715 36

Human female reproductive tract tissues were analysed for estrogen and progestogen receptor content in the presence or absence of sodium molybdate immediately after removal at surgery. Other fractions of the tissue were stored in liquid nitrogen and similarly analysed after 2, 4, 6 and 8 weeks storage. The results showed that at all times the apparent receptor content for both steroids was significantly higher (P less than 0.001) and Kd values were significantly lower (P less than 0.02) in assays carried out with 10 mM molybdate added to the buffer systems. Furthermore, as soon as either whole tissue or tissue cytosol was frozen for storage, receptors were "lost" with values decreasing by approximately 30% for both steroid receptors. However, once frozen in liquid nitrogen tissue receptor content remained stable over the eight weeks of study. It is recommended that laboratories standardize techniques to allow valid comparisons of results.
Steroids 1982 Aug
PMID:The effect of storage time and molybdate on steroid receptors in gynaecological tissues. 715 51

Syntheses of 15 alpha- and 15 beta-carboxymethyltestosterone (15 alpha- and 15 beta-CMT) were investigated in order to prepare testosterone-bovine serum albumin conjugates for radioimmunoassays of testosterone. A mixture of 15 alpha- and 15 beta-bis(ethoxycarbonyl)methyl-3 beta-hydroxy-5-androsten-17-one (IIa and IIb) obtained by a reaction of 3 beta-hydroxy-5,15-androstadien-17-one (I) and sodium diethyl malonate was oxidized to afford a mixture of 15 alpha- and 15 beta-bis(ethoxycarbonyl)methyl-4-androstene-3, 17-dione (Va and Vb). After the separation by silica gel chromatography, each epimer obtained was hydrolyzed by acid, followed by decarboxylation, and selective reduction of the 17-ketone to give 15 alpha- and 15 beta-CMT. The antisera, generated in rabbits by immunization with the bovine serum albumin (BSA) conjugates of 15 alpha- and 15 beta-CMT, respectively, exhibited high specificity for testosterone.
Steroids 1982 Sep
PMID:Syntheses of 15 alpha- and 15 beta-carboxymethyltestosterone bovine serum albumin conjugates: characteristics of the antisera to testosterone. 718 1


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