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

Effects of steroids on the accumulation of glycoprotein gonadotropin (GTH) in pituitaries of juvenile trout were investigated by means of scanning cytophotometry applied to immunocytochemical preparations, and with the use of a radioimmunoassay. Effects on other aspects of GTH-cell activity were analyzed by measuring the size of the gonadotrops and their nuclei. Progesterone added to aquarium water and methyltestosterone incorporated into the food showed a pronounced stimulatory effect on the accumulation of GTH. To a lesser extent, treatment with cortisol, cortisone, and desoxycorticosterone acetate administered to aquarium water, and 11 beta-hydroxy-androstenedione added to the food resulted in an increase of the hypophysial content of GTH. Steroids stimulating the accumulation of GTH in the pituitary also exhibited a positive effect on GTH-cell activity as indicated by an increase in the size of gonadotropic cells. Progesterone incorporated into the food did not influence the GTH-content and the GTH-cell activity. It is suggested that the route of administration of an exogenous steroid is essential for its effect on GTH cells in trout. Comparison of GTH values reveals an excellent correlation between the data from the radioimmunoassay and those from the corresponding densitometric measurements. No correlation was observed between values of morphometrically determined GTH-cell activity and the densitometric values reflecting hypophysial GTH content.
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PMID:Accumulation of glycoprotein gonadotropin in the pituitary of juvenile rainbow trout in response to androgens and C21-steroids, including 11-steroids. 671 90

The treatment of pulmonary aspiration of gastric contents remains largely empirical. The purpose of the present study was to evaluate the effect of methylprednisolone administration (30 mg/kg) on alveolar-capillary membrane permeability after pulmonary acid aspiration in dogs. Alveolar-capillary membrane permeability was assessed by several methods. Extravascular lung water volume (EVLW), extravasation of 125I-serum albumin (RISA) into lung parenchyma, and albumin leak into the alveolar spaces were measured. EVLW increased progressively from 5.5 +/- 0.6 to 20.0 +/- 2.3 ml/kg in Group I (Acid) and from 5.4 +/- 1.2 to 22.1 +/- 3.1 ml/kg in Group II (Acid + Steroids) over the 5 hours after acid injury. The ratio of Lung Extravascular RISA to Plasma RISA was 0.56 +/- 0.14 and 0.58 +/- 0.14 in Group I and Group II, respectively (normal = 0.19 +/- 0.06). The tracheal albumin to plasma albumin ratio remained near 1.0 from 2 hours to 5 hours post-aspiration in both groups. This study demonstrated that pulmonary acid injury resulted in a marked increase in alveolar-capillary permeability to albumin, smaller solutes, and water which was not ameliorated by the administration of methylprednisolone.
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PMID:The effect of intravenous steroids on alveolar-capillary membrane permeability in pulmonary acid injury. 707 96

Rapid separation of gonadal steroids in the progesterone (delta 4) and pregnenolone pathway (delta 5) has been accomplished by the use of high performance liquid chromatography (HPLC). Two HPLC systems are utilized. THe first requires the use of two separate radial compression columns (C-18 and C-8), with steroids being eluted with a methanol-water gradient. The second employs a stainless steel C-18 (reversed phase) column with a 12% octadecylsilane coating. The latter system separates seven of the eight steroids in the delta 4 and delta 5 pathways in thirty-five minutes. For the quantitation of steroids directly, integration of the peak areas, using 254 nm absorption for the delta 4 pathway steroids (5 ng minimum limit), and 210 nm absorption for the delta 5 pathway steroids (25 ng minimum limit) is used. For the quantitation of radiolabeled metabolites resulting from incubation of gonadal tissue with radiolabeled steroid precursors, either one of two methods is used: (1) the eluent can be recovered from the HPLC using a fraction collector, and counted in liquid scintillation counter or (2) the entire eluent (or a portion of it) can be counted immediately by directing the flow through a radioactivity detector.
Steroids 1982 Jan
PMID:High performance liquid chromatography of steroid metabolites in the pregnenolone and progesterone pathways. 708 Jan 12

A method has been developed for quantification of total free and conjugated bile acids separated on silica gel HR coated thin-layer chromatography plates. Aliquots of bile acid solutions are applied to channeled plates which are developed with either ethyl acetates: isooctane:glacial acetic acid 10:10:2 v/v for free bile acid separation, or chloroform:methanol:glacial acetic acid:water 130:50:4:8 V/V for conjugated bile acid separation. Bile acids are determined directly in serial areas of silica gel by treating gel areas suspended in tris buffer with resazurin reagent. The method is quantitative and as little as 0.1 microgram of bile acid is readily determined. Application of the method to determinations of bile acids in crude fecal extracts is described.
Steroids 1982 Mar
PMID:Thin-layer separation and quantification of bile acids. 709 27

A technique was developed to separate six androgens (testosterone, dihydrotestosterone, androstenedione, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 alpha-androstane-3 beta, 17 beta-diol, and androsterone) by high performance liquid chromatography prior to quantitation by specific radioimmunoassay systems. Methanol:water (60:40 v:v) was used as the solvent system with a C18 reversed-phase column. The method was verified and used to quantitate the androgens in serum from adult rams bled every 20 minutes for 6 hours and yearling bulls bled every 30 minutes for 8 hours. Concentrations of all 6 androgens varied in an episodic manner with testosterone being the dominant androgen.
Steroids 1982 Oct
PMID:Quantitation of six androgens by combined high performance liquid chromatography and radioimmunoassay. 717 Jul 48

The usefulness of recrystallization in establishing the radiochemical purity of steroids is widely recognized, but the potential limitations of the technique have received little attention. The current study reports the failure of standard recrystallization procedures using methanol/water as the solvent pair to separate contaminating 14C-17-hydroxyprogesterone (17-hydroxy-4-pregnene-3, 20-dione) from 3H- and 14C-labeled 11-deoxycortisol (17,21-dihydroxy-4-pregnene-3,20-dione) despite ten serial crystallizations. The standard criteria of radiochemical purity were met despite gross impurity of the crystals as evidenced by thin layer chromatography. Thus, recrystallization may, under certain conditions, yield misleading results when employed as the only method for identifying radioactive steroids. These observations illustrate the importance of an optimal choice of solvent and crystallization conditions, and emphasize the need for confirmation by derivative formation and chromatography.
Steroids 1980 Apr
PMID:Potential limitations of recrystallization for the definitive identification of radioactive steroids. 737 25

A study of the degree of water elimination from ions derived from spirostan-3-ols by electron bombardment has shown that the loss is greatest from those ions produced by the 5 beta-spirostan-3 alpha-ols, less from the 5 beta-spirostan-3 beta-ols and the 5 alpha-spirostan-3 alpha-ols, which give losses of the same order of magnitude; and least from the 5 alpha-spirostan-3 beta-ols. The extent of water elimination can be used to help characterise spirostan-3-ols isolated from plant materials.
Steroids 1980 Sep
PMID:Configurational assignments to spirostan-3-ols by mass spectrometry. 743 2

The reaction of 3 beta, 17 beta-diacetoxy-4-estrene with N-bromoacetamide in a two phase ether/water solvent mixture gave 5-bromo-4 beta, 17 beta-diacetoxy-5 alpha-estran-3 beta-ol as the major product (75%). Four minor products were also isolated and identified. These were: 4 alpha-bromo-3 beta, 17 beta-diacetoxy-5 alpha-estran-5-ol (5%), 5-bromo-3 beta, 17 beta-diacetoxy-5 alpha-estran-4 beta-ol (6%), 5-bromo-4 alpha, 17 beta-diacetoxy-5 alpha-estran-3 beta-ol (3%), and 4 beta-bromo-3 beta, 17 beta-diacetoxy-5 alpha-estran-5-ol (4%). The 5-bromo-4 beta, 17 beta-diacetoxy-5 alpha-estran-3 beta-ol was equilibrated by heating with oxalic acid in refluxing benzene for ca. 16 h to give a mixture of it and 5-bromo-3 beta, 17 beta-diacetoxy-5 alpha-estran-4 beta-ol in the ratio of 16:84 respectively. A similar equilibration mixture (14:86) was obtained under identical conditions when 5-bromo-3 beta, 17 beta-diacetoxy-5 alpha-estran-4 beta-ol was the starting material.
Steroids 1980 Oct
PMID:The addition of hypobromous acid to 3 beta, 17 beta-diacetoxy-4-estrene and an equilibration study involving neighboring group participation by the A-ring acetoxy group. 744 95

Progesterone-BSA (bovine serum albumin) conjugates which contain up to 47 steroid molecules linked to a BSA molecule have been prepared by the activated ester method, the conjugation step being carried out in reversed micellar solutions of sodium di(2-ethylhexyl) sulphosuccinate (AOT) in octane. The number of incorporated steroid molecules increases on passing to increased water/AOT ratios at the given activated steroid/BSA ratio. The results show that the reversed micellar medium would be useful for preparation of conjugates of hydrophobic steroids with proteins in respect to simplicity and ease in obtaining conjugates with high steroid/protein ratios.
Steroids 1993 Nov
PMID:Preparation of conjugates of progesterone with bovine serum albumin in the reversed micellar medium. 750 59

Mifepristone (RU 486), used clinically for the termination of early pregnancy, and its acetyl and 13-retro (13 alpha) analogs show potent antiproliferative effects against estrogen-dependent human breast tumors and endometriosis. However, there has been no report on direct inhibition of aromatase by antiprogesterones. Aromatase inhibitors have been shown to be effective against estrogen-dependent breast cancer. We evaluated the inhibition of aromatase by various antiprogestins (ZK 112.993, ZK 98.734, ZK 114.043, ZK 98.299, and ZK 114.863). Human placental microsomes were incubated with [1 beta-3H,4-14C] androstenedione (3-114 nM) in the presence of NADPH, with or without putative inhibitors (10-200 microM). Aromatase activity was assessed by tritium release to water from the 1 beta-position of the substrate. ZK 112.993 and ZK 98.734 did not show any inhibitory effect. The statistical analysis of the data using standard errors was obtained from replicate experiments. ZK 114.043 showed slight inhibition with a Ki of 54.8 +/- 6.4 microM (m +/- SE, n = 6) against androstenedione aromatization. The two 13-retro-steroids, ZK 98.299 and ZK 114.863, showed aromatase inhibition with Ki values of 19.0 +/- 1.5 microM (n = 7) and 12.7 +/- 0.94 microM (n = 7), respectively, which is weak with respect to some known potent inhibitors, but significant when compared with the other antiprogestins which were tested. The results suggest that the unnatural 13-retro-antiprogestin conformation may have a better fit to the aromatase active site than the natural 13 beta-antiprogestin conformation. (Steroids 60:234-238, 1995).
Steroids 1995 Feb
PMID:Inhibition of aromatase activity in human placental microsomes by 13-retro-antiprogestins. 761 91


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