935 resultados para Gonadal steroids
Resumo:
Ethylestrenol (17β Hydroxy-17alpha-ethyl-estr-4-en-3-one) and Stanozolal (17β-Hydroxy-17alpha-methyl 1-5 alpha-androstano-(3,2-C)-pyrazole), both synthetic androgenic steroids, were fed via diet at 3ppm to the fry of catla, rohu and silver carp which were reared up to fingerling stage over a period of 167-172 days in earthen ponds. Ethylestrenol enhanced growth in silver carp and rohu but retarded growth in catla. Stanozolal depressed growth in all the 3 species. Length-weight relationship for these fry had been worked out and the relative condition factor in all the cases was very close to or slightly above 1.0.
Resumo:
Two synthetic androgenic steroids, Ethylestrenol (17 β - Hydroxy - 17 α ethyl - estr - 4 - en - 3 - one) and Stanozolal (17 β - Hydroxy- 17 α - methyl - 5 a - androstano - 3, 2 - C - pyrazole) were fed via diet at 3 ppm to the spawn of Rohu and Mrigal which were reared up to fry stage over a period of 15 days in earthen carp nurseries. Both hormones enhanced growth of spawn. A maximum of 25.78% increase in length and 25.69% increase in weight as compared to the controls has been recorded. Growth rate was recorded to be 0.8 mm & 2.48 mg/day (control), and 1.13 mm & 2.67 mg/day (Stanozolol treated) in case of Mrigal spawn; and 0.91 mm & 2.39 mg/day (control), 1.12 mm & 2.90 mg/day (Ethylestrenol treated), and 1.10 mm & 2.57 mg/day (Stanozolol treated) in case of Rohu spawn. A decrease in the values of Relative Condition Factor upon hormone administration was also noticed.
Resumo:
This study was carried out to seasonal determination of some morphological characteristics, Seasonal fecundity, Seasonal fluctuations of vertebrate-type steroids and seasonal analysis of gonadal histology in both female and male sexes of freshwater crayfish (Astacus leptodactylus Eschscholtz 1823) in the area of Aras dam Lake. Crayfish were collected respectively in June, August, November (2011) and January (2012). The average length and weight of male crayfish was higher than that of females. %GSI of females fluctuated within an extended range (between 0.6 and 13.5% from June to January). Both of synchronous and asynchronous ovaries were seen in August sampled ovaries; however asynchronous form was higher than another. The annual reproductive cycle of male A. leptodactylus was surveyed by study on the seasonal changes of the external appearance of the testes and vasa deferentia, fluctuations in the gonadosomatic index (GSI%) and the histological analysis of the male reproductive system. Based on the histological differentiation of testis, spermatogenisis devided to 5 separated stages. The findings suggested asynchronous testis in the species A.leptodactylus. The presence of primary spermatophore layer may help keeping spermatozoa alive while the secondary spermatophore layer may produces spermatophore or synthesize of acellular material which forms spermatophre. Pleopodal fecundity was 37.3%lower than ovarian fecundity observed. The significantly higher number of eggs attached to 3rd and 4th pairs of pleopods. The egg number and gonadosomatic index increased with female size while egg weight and egg diameter didn’t increase with female size. Hemolymph levels of 17β-estradiol and progesterone followed a similar fluctuation pattern with % GSI in females, while testosterone didn’t follow the mentioned pattern. The testis of November sampled crayfish presented significantly higher gonadosomatic (%GSI) index (P < 0.05).The most observed gonadosomaticindices were 13.5%(forfemales) and 1.21% (for males, in autumn. Althogh the lowest GSI was (0.50%) formales in spring and (0.26%0 for spent females in January. Testosterone which followed a similar pattern with %GSI in males increased remarkably in November. 17β-estradiol increased strictly in January. The strictly enhancement of the three estroid hormones in January in both male and female sexes could bedue totheir stimulating role in in spermatophre and egg lying in the mating season (In January). Most of the ovaries followed the asynchoronous growth pattern. Also the testes presented asynchoronous growth pattern in autumn.
Resumo:
Fluorotelomer alcohols (FTOHs) have shown estrogenic activity in vitro and in vivo, but the mechanism of this activity is not known. In this study, 18-week-old zebrafish (Danio rerio) were exposed to 0, 0.03, 0.3 and 3.0 mg/l 1H, 1H, 2H, 2H-perfluorooctan-1-ol (6:2 ETCH) for 7 days, and the effects on plasma sex hormone levels were measured followed by use of real-time PCR to examine selected gene expression in hypothalamic-pituitary-gonadal (HPG) axis and liver. Exposure to 6:2 FTOH significantly increased plasma estradiol (E2) and testosterone (T) levels in both males and females. Furthermore, the ratio of T/E2 was reduced in females while increased in males. In females, the increase of E2 was accompanied by up-regulated hepatic estrogenic receptor alpha (ER alpha) and vitellogenin (VTG1 and VTG3) expression. In males, the elevation of the T level is consistent with the up-regulation of cytochrome P450 c17 alpha-hydroxylase, 17, 20-lase (CYP17) and the down-regulation of cytochrome P450 aromatase A (CYP19A). The present study demonstrated that waterborne exposure to 6:2 FTOH alter plasma sex hormone levels and the ratio of T/E2, as well as the transcriptional profiles of some genes in the HPG axis and liver. The results suggested that FTOHs may disturb fish reproduction through endocrine disrupted activity. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
This paper describes a novel method that applies pressure-assisted field-amplified sample injection with reverse migrating micelles (PA-FASI-RMM) for the online concentration of neutral analytes in MEKC with a low-pH BGE. After injection of a plug of water into the separation capillary, negative voltage and positive pressure were simultaneously applied to initialize PA-FASI-RMM injection. The hydrodynamic flow generated by the positive pressure compensated the reverse EOF in the water plug and allowed the water plug to remain in the capillary during FASI with reverse migrating micelles (FASI-RMM) to obtain a much longer injection time than usual, which improved stacking efficiency greatly. Equations describing this injection mode were introduced and were supported by experimental results. For a 450-s online PA-FASI-RMM injection, three orders of magnitude sample enhancement in terms of peak area could be observed for the steroids and an achievement of detection limits was between 1 and 10 ng/mL.
Resumo:
Generating transgenic fish with desirable traits (e.g., rapid growth, larger size, etc.) for commercial use has been hampered by concerns for biosafety and competition if these fish are released into the environment. These obstacles may be overcome by producing transgenic fish that are sterile, possibly by inhibiting hormones related to reproduction. In vertebrates, synthesis and release of gonadotropin (GtH) and other reproductive hormones is mediated by gonadotropin-releasing hormone (GnRH). Recently two cDNA sequences encoding salmon-type GnRH (sGnRH) decapeptides were cloned from common carp (Cyprinus carpio). This study analyzed the expression of these two genes using real-time polymerase chain reaction (RT-PCR) in different tissues carp at varying developmental stages. Transcripts of both genes were detected in ovary and testis in mature and regressed, but not in juvenile carp. To evaluate the effects of sGnRH inhibition, the recombinant gene CAsGnRHpc-antisense, expressing antisense sGnRH RNA driven by a carp beta-actin promoter, was constructed. Blocking sGnRH expression using antisense sGnRH significantly decreased GtH in the blood of male transgenic carp. Furthermore, some antisense transgenic fish had no gonadal development and were completely sterile. These data demonstrate that sGnRH is important for GtH synthesis and development of reproductive organs in carp. Also, the antisense sGnRH strategy may prove effective in generating sterile transgenic fish, eliminating environmental concerns these fish may raise. (c) 2007 Published by Elsevier B.V.
Resumo:
Cytochrome P450 3A4 (CYP3A4), a major member of cytochrome P450 isoenzymes, metabolizes the majority of steroids in 6beta-position. For the purpose of determining requisite structural features of a series of structurally related steroids for CYP3A4-mediated metabolism, three-dimensional pharmacophore modeling as well as electrotopological state map were conducted for 15 steroids. Though prior studies speculated that the chemical reactivity of the allylic 6beta-position might have a greater influence on CYP3A4 selective 6-hydroxylation than steric constraints in the enzyme, our results reveal that for CYP3A4 steroidal substrates, it is not the chemical reactivity of atoms at 6beta-site, but the pharmacophoric features, i.e. the two hydrophobic rings together with two H-bond donors, that act as the key factors responsible for detemining the CYP3A4 selective 6-hydroxylation of steroids. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as beta-lawsaritol (1), saringosterol (2), 24-hydroperoxy-24-vinyl-cholesterol (3), beta-stigmasterol (4), stigmast-4-en-3 alpha, 6 beta-diol (5), 29-hydroxystigmasta-5, 24 (28)-dien-3 beta-ol (6). All these compounds were obtained from this genus for the first time and they were inactive (IC50 > 10 mu g /ml) against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.
Resumo:
Three β-hydroxysteroid dehydrogenase/Δ5-Δ4-isomerase (3β-HSD) catalyze the oxidative conversion of Δ5-3β-hydroxysteroids to the Δ4-3-keto configuration and is therefore essential for the biosynthesis of all classes of hormonal steroids, namely progesterone, glucocorticoids, mineralocorticoids, androgens, and estrogens. Using human 3β-HSD cDNA as probe, a human 3β-HSD gene was isolated from a λ-EMBL3 library of leucocyte genomic DNA. A fragment of 3β-HSD genomic DNA was also obtained by amplification of genomic DNA using the polymerase chain reaction. The 3β-HSD gene contains a 5′-untranslated exon of 53 base pairs (bp) and three successive translated exons of 232, 165, and 1218 bp, respectively, separated by introns of 129, 3883, and 2162 bp. The transcription start site is situated 267 nucleotides upstream from the ATG initiating codon. DNA sequence analysis of the 5′-flanking region reveals the existence of a putative TATA box (ATAAA) situated 28 nucleotides upstream from the transcription start site while a putative CAAT binding sequence is located 57 nucleotides upstream from the TATA box. Expression of a cDNA insert containing the coding region of 3β-HSD in nonsteroidogenic cells shows that the gene encodes a single 42-kDa protein containing both 3β-hydroxysteroid dehydrogenase and Δ5-Δ4-isomerase activities. Moreover, all natural steroid substrates tested are transformed with comparable efficiency by the enzyme. In addition to its importance for studies of the regulation of expression of 3β-HSD in gonadal as well as peripheral tissues, knowledge of the structure of the human 3β-HSD gene should permit investigation of the molecular defects responsible for 3β-HSD deficiency, the second most common cause of adrenal hyperplasia in children.
Resumo:
Although steroid hormones are known to play a predominant role in the regulation of cell growth in hormone-sensitive cancers, their mechanisms of action, especially their interaction with growth factors and/or growth inhibitors, is poorly understood. We have recently observed that the effects of androgens and estrogens on the expression of the major protein found in human breast gross cystic disease fluid, protein-24, are opposite to their respective action on cell proliferation in human breast cancer cell lines. Somewhat surprisingly, the recent elucidation of the amino acid sequence of this progesterone binding protein reveals that this tumor marker is apolipoprotein D (apo D), a member of a superfamily of lipophilic ligand carrier proteins. The present study was designed to determine whether apo D is secreted by human prostate cancer cells and could thus be a new marker of steroid action in these cancer cells, and whether the sex steroid-induced stimulation of apo D secretion coincides with inhibition of cell proliferation. We took advantage of the biphasic pattern of the effect of steroids on the proliferation of the human prostate cancer LNCaP cell line, which offers the opportunity to discriminate between positive and negative steroid receptor-regulated cell growth processes. A 10-day exposure to low concentrations of dihydrotestosterone and testosterone caused a potent stimulation of LNCaP cell proliferation, whereas incubation with higher concentrations of these androgens led to a progressive decrease in cell proliferation towards basal levels. The biphasic action of androgens was also observed on apo D secretion, the effects on apo D secretion being inversely related to their action on LNCaP cell proliferation. Similar opposite biphasic effects were also observed with 9 other steroids, thus indicating that the stimulation of secretion of this new biochemical marker coincides with inhibition of cell proliferation in LNCaP human prostatic cancer cells.
Resumo:
The performance of three conventional enzyme and radioimmunoassays routinely used to detect residues of anabolic steroids in cattle sera were compared with dissociation enhanced lanthanide fluorescence immunoassay (DELFIA) kits designed for the hospital market. Slight modifications to the kit reagents were required for the analysis of bovine sera. Owing to the large sample volumes used in conventional assays, detection limits were generally better than those obtained with DELFIA kits, however, assay reproducibility was enhanced using the DELFIA technology. Comparison of sera obtained from cattle implanted with anabolic steroids revealed a good correlation between alternate methods (r(2) from 0.91 to 0.97). The DELFIA kits offer a faster method for measuring estradiol, progesterone and testosterone with adequate sensitivity and in a safer environment than that encountered using radioimmunoassays.
Resumo:
To determine whether a single course of antenatal dexamethasone alters resting cortisol at 3, 8 and 18 months corrected age in preterm infants.