Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein-bound steroids can be separated from free steroids using microcolumns of silica gel coated with an hydrophobic (octadecyl) solid phase. The bound fraction is eluted in the assay buffer, whereas the free fraction is retained quantitatively on the column in the first step and can be recovered in methanol. Both fractions can be quantitated directly (e.g. by liquid scintillation spectrometry when using radioactive ligands) or kept for further analysis (e.g. by TLC, HPLC etc.). Separation of the bound and free fractions is rapid, accurate and reproducible; intra- and inter-assay coefficients of variation are lower than 5 and 10%, respectively. Recovery of radioactive steroids is high (usually over 85%) and can be estimated separately for each sample. Since assay blanks are very low (typically less than 0.1% of input), this new method, which could be termed "hydrophobic interaction chromatography" (HIC), should prove especially useful for the development of sensitive binding assays, particularly in the field of steroid receptors. The HIC method compared well with three methods currently used for steroid binding assays, namely adsorption of unbound steroids on dextran-coated charcoal, gel filtration on Sephadex LH-20 and adsorption of steroid-protein complexes on DEAE-cellulose filters. Examples of application described here include studies on human plasma sex hormone binding globulin (SHBG) and SP2 placental protein (saturation analysis, binding specificity etc.), the separation of antibody-bound steroids in a radioimmunoassay and the estimation of androgen binding to rat epididymal androgen binding protein (rABP). Receptor assays are illustrated by saturation analysis of the mouse uterine oestrogen receptor and of the androgen receptor in the human genital skin.
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PMID:Hydrophobic interaction chromatography (HIC) for the separation of protein-bound and free steroids. Application to binding protein and receptor assays. 409 24

The sites of action and the physiological role of oestrogens in the male reproductive tract are poorly understood. We have undertaken a systematic study of the immunoexpression of oestrogen receptor-alpha (ER alpha) in the male rat from late fetal life through to adulthood and compared the findings with results obtained in the marmoset monkey (Callithrix jacchus) from neonatal to adult life. The testes, rete testis, efferent ducts and epididymis were examined from normal male rats (aged 4, 8, 10, 15, 20, 25, 38, 48 and 90 days) and from male rat fetuses on days 17.5 and 18.5 of gestation; comparable tissues were examined from neonatal, infantile, peripubertal and adult marmosets aged 8, 18-24, 54-62 and 92-112 weeks respectively. Immunolocalisation of ER alpha used antigen retrieval and a monoclonal antibody directed to the N-terminus, which had proved superior to six other antisera tested. ER alpha was immunoexpressed in interstitial cells, including the fetal/ neonatal generation of Leydig cells, in both the rat and marmoset. In the rat, the adult generation of Leydig cells were also immunopositive for ER alpha whereas the comparable cells in the marmoset were only weakly immunopositive. ER alpha was not expressed in Sertoli cells, peritubular myoid cells, blood vessels or germ cells at any time in either species. In late fetal life in the rat, ER alpha was immunoexpressed in cells surrounding the mesonephric tubules, whereas postnatally it was expressed in the epithelium of the rete testis and efferent ducts at all ages from 4 to 90 days; this immunoexpression was most pronounced in the efferent ducts. In the marmoset, the efferent ducts, but not the rete testis, also showed intense immunoexpression of ER alpha. Apart from sporadic immunostaining for ER alpha in the epididymal duct of the rat in the neonatal period, the caput, corpus and cauda epididymis were negative for immunoexpression of ER alpha at all ages in both species. These findings suggest that the main actions of oestrogens in the male reproductive tract, mediated by ER alpha, are related to the development and function of the efferent ducts and the Leydig cells. In consideration of data from this and previous studies of oestrogen binding, we predict possible sites of expression of other oestrogen receptors (e.g. ER beta) in Sertoli cells and the epididymis. Interactive effects, related to the relative levels of androgens and oestrogens, could be physiologically important in the excurrent ducts of the adult testis.
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PMID:Immunolocalisation of oestrogen receptor-alpha within the testis and excurrent ducts of the rat and marmoset monkey from perinatal life to adulthood. 920 3

Many of the reproductive toxicants have primary effects on the testis, which potentially overshadow effects downstream on the efferent ducts and epididymis. The specific target of these effects depends upon the dosage and time response. It is often necessary to design experiments that separate testosterone-dependent responses arising in the testis from direct effects on epididymal tissues and spermatozoa, to uncover the mechanisms of toxicity in excurrent ducts. Recent studies have confirmed that chemicals can also alter the time required for sperm transport through the epididymis. Currently there are approximately twenty chemicals that can be classified as epididymal toxicants. There are fewer toxicants reported for the efferent ducts, but a few overlap with epididymal effects. The benzimidazole carbamates, like many efferent ductal toxicants, induce occlusions and subsequent testicular atrophy. The mechanisms appear to be related to fluid reabsorption, sperm stasis, followed by leukocyte chemotaxis, sperm granulomas, fibrosis and often the formation of abnormal microcanals. Disruption of oestrogen receptor function in the efferent ducts also interferes with fluid reabsorption and results in testicular swelling and seminiferous tubular atrophy. Thus, studies in which testicular atrophy occurs after chronic or subchronic exposures should be examined for lesions in efferent ducts and head of the epididymis. Such lesions can lead to permanent infertility.
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PMID:Effects of environmental toxicants on the efferent ducts, epididymis and fertility. 1064 84

The cellular localization of two oestrogen receptor (ER) subtypes, ER alpha and ER beta, was investigated in neonatal, postnatal, immature and adult male rats to determine whether these receptor subtypes are differentially expressed in prostate and epididymis. A monoclonal antibody against ER alpha and two polyclonal ER beta antibodies were used. Paraffin sections revealed a specific nuclear immunoreaction product in certain cells but not in others. In the epididymis, nuclear ER alpha immunoreactivity (IR) was detected in epithelial cells of efferent ductules and initial segments as well as in connective tissue surrounding the tubules in caput, corpus and cauda. No IR was observed in rete testis. Epithelial cells of the prostate lacked ER alpha IR, but connective tissue cells surrounding prostatic buds in the early neonatal period revealed IR. In prostate, ER beta IR was expressed in epithelial cells of the ventral and dorsolateral lobes, but the IR intensity was higher in the ventral lobe. In neonatal rats, ER beta was expressed in the epididymis but not in the prostate gland. Weak ER beta expression was found in the prostates of 5-day-old rats, and the reaction increased in intensity thereafter. In the epididymis, a similar developmental expression pattern of ER beta was observed. ER beta expression in prostate and epididymis was similar to expression of androgen receptors reported previously for these organs. The results support that both ER alpha and ER beta may be involved in oestrogen modulation of prostate and epididymal functions.
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PMID:Oestrogen receptor alpha and beta in rat prostate and epididymis. 1102 22

1. gamma-Glutamyl-transpeptidase (gamma-GTP), present at low levels in the testis, seminal vesicle, prostate gland and epididymis in rat at 4 days of age, showed rapid developmental increases at the time of weaning. 2. Administration of nonylphenols (NP) to the neonatal male rat pup (from days 1 to 15) impaired the subsequent development of gamma-GTP in the epididymis but not in the testis, seminal vesicles or prostate gland. 3. Single injection of NP to weaned pups at approximately 22 days of age decreased gamma-GTP in the epididymis but not in other male accessory sex organs. This effect was transient, dose-dependent and blocked by the oestrogen receptor-specific antagonist ICI 182,780. 4. Single injection of oestradiol to weaned rat at approximately 22 days of age also decreased gamma-GTP in the epididymis but not in the testis, prostate gland or seminal vesicles. 5. In in vitro assays, NP did not inhibit epididymal gamma-GTP activity even at 100 microM final concentration. Under similar conditions, acivicin, a specific inhibitor for gamma-GTP, showed a dose-dependent inhibition of gamma-GTP activity. 6. It is suggested that NP impair gamma-GTP expression in the epididymis of developing male rat and act in part via the oestrogen receptor.
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PMID:Modulation of rat epididymal gamma-glutamyl transpeptidase by nonylphenols. 1103 10

Primary cultures of the differentiated, adult epididymal duct epithelium were immortalized by retroviral transduction with the simian virus (SV)40 large T antigen. The canine epididymis was chosen here as a model with high human relevance, representing a convenient and acceptable source of differentiated epididymal tissue and, compared to other animal models, expressing a relatively large number of gene products which are also expressed by the human epididymis. To determine whether the immortalized canine epididymal (IMCE) cells retained a phenotype comparable to the original tissue, epithelial cytokeratins, various epididymal transcription factors as well as mRNAs encoding abundant epididymal secretory proteins, were studied as molecular markers. All IMCE populations obtained after transduction were of epithelial origin. The nuclear androgen receptor (AR) and the polyoma enhancer activator (PEA3), as well as the epididymal mRNA encoding the canine counterparts of human HE1, HE4 and HE5/CD52 epididymal mRNA, were retained in all populations tested. The majority of tested clones were oestrogen receptor ERalpha-positive, but ERbeta-negative, while one ERalpha-negative cell population was positive for ERbeta. The IMCE populations described thus represent useful permanent tools for studying gene expression of the epididymal duct epithelium, and for other types of experiments, examples including drug effects and toxicity on the epididymis.
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PMID:Epididymal epithelium immortalized by simian virus 40 large T antigen: a model to study epididymal gene expression. 1157 62

The present study was conducted to characterise and localise the progesterone receptor (PR) on canine spermatozoa. Using a progesterone-bovine serum albumin-fluorescein isothiocyanate conjugate (PBF) and different monoclonal antibodies (C262 and NCL-PGR against the steroid binding domain and N-terminus of intracellular PR, respectively, and h151 against the hinge domain of the intracellular oestrogen receptor), the PR was identified on the plasma membrane over the acrosomal region. Two proteins (54 kDa and 65 kDa) were detected by recognition of the three monoclonal antibodies using Western blotting. PBF labelling was observed in the majority of cauda epididymal spermatozoa (63 +/- 4%), but this labelling was markedly reduced (33 +/- 17%) after the addition of canine seminal plasma. Over a 7-h capacitation, the proportion of ejaculated spermatozoa exhibiting PBF labelling (indicating the presence of the PR) increased from 18 +/- 10% (onset) to 59 +/- 7% by 5 h, where it plateaued. Progesterone (P 4 ) induced the acrosome reaction (AR) in a dose-dependent manner (0, 0.1, 1 and 10 ug/mL P 4 corresponding to 10 +/- 5%, 16 +/- 9%, 23 +/- 7% and 30 +/- 7%). Pre-treatment of capacitated spermatozoa with canine seminal plasma reduced the incidence of the P 4 -induced AR (12 +/- 5%). In addition, treatment with the monoclonal antibodies significantly reduced the incidence of the P 4 -induced AR (10 microg/mL) in capacitated ejaculated spermatozoa from 19 +/- 6% to 11 +/- 4% (h151, 1 : 10) and 12 +/- 6% (C262, 1 : 10), respectively. A typical Scatchard plot revealed one binding with high affinity and low capacity, and another binding with low affinity and high capacity, suggesting at least two different characteristic PR. Taken together, these results demonstrate that P 4 induced the AR in a dose-dependent manner via functional transmembranal receptors in the acrosomal region of the canine sperm plasma membrane. The characteristics of this membrane receptor seem similar to those of other mammalian spermatozoa, and it shows structural homology to the intracellular PR.
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PMID:Characterisation of the progesterone receptor on canine spermatozoa. 1636 28

Phytoestrogens are plant-derived compounds with oestrogenic activity. They are common in both human and animal diets, particularly through soy-based foods. This study assessed whether exposure of adult male rats to a high phytoestrogen diet for 3-25 days affected their fertility, and assessed possible mechanisms through which phytoestrogens may disrupt fertility. Adult males, fed a high phytoestrogen diet for 3 days, demonstrated significantly reduced fecundity. This effect was transient, with fecundity returning to control levels by day 12. The expression of oestrogen receptor-alpha and androgen receptor mRNA was increased in the initial segment of the epididymis, but decreased in the cauda epididymis following 3 days on the high phytoestrogen diet. Epididymal sperm counts cannot account for the reduction in fertility at day 3. However, lipid peroxidation of epididymal sperm was significantly increased in animals fed a high phytoestrogen diet for 3 days. Disruption of the steroid regulation of the epididymis by phytoestrogens may alter its function, resulting in decreased quality of sperm, and thereby reducing fecundity.
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PMID:Acute exposure of adult male rats to dietary phytoestrogens reduces fecundity and alters epididymal steroid hormone receptor expression. 1673 87

A role for oestrogen in regulating fluid reabsorption in the monkey epididymis was recently demonstrated. Here, these studies are extended to identify potential oestrogen-regulated proteins in the cauda region of monkey epididymis treated with vehicle and oestrogen receptor antagonist (ICI 182780). Two-dimensional electrophoretic analysis was used to identify the proteins. The results indicated down-regulation of WNT4 in the ICI-182780-treated monkey cauda. In addition, the Wnt4 mRNA concentration was also reduced in the caput regions of ICI-182780- treated rats and oestrogen receptor knockout mice. WNT4 is a key regulator of gonadal differentiation in humans and mice and plays a pivotal role in early mouse embryogenesis. The results of the present study establish the presence of WNT4 in the monkey epididymis and its regulation by oestrogen, and suggest a role for WNT4 in maintaining epididymal homeostasis.
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PMID:Oestrogenic regulation and differential expression of WNT4 in the bonnet monkey and rodent epididymis. 1940 Sep 99

The role of oestrogens in epididymal function is still unclear. Knockout of the oestrogen receptor ESR1 (Esr1(-/-) ) or treatment with the anti-oestrogen Fulvestrant affect epididymal milieu and sperm motility. We investigated the effect of in vivo treatment of rats with Fulvestrant on: (i) expression of genes that may be important for the architecture and function of the epididymal epithelium: prominins 1 and 2, metalloproteinase 7, claudin 7, beta-catenin and cadherin 13, and (ii) levels of oestradiol and testosterone, and expression of oestrogen and androgen receptors, in the initial segment (IS), caput, corpus and cauda epididymis. Fulvestrant (i) reduced gene expression of prominin 1 (variant 1) in the caput, reduced prominin 1 protein content in the caput epididymis and in the efferent ductules, and increased the localization of prominin 1 in microvilli of the caput and corpus; (ii) reduced gene expression of prominin 2 in the corpus and cauda epididymis; (iii) increased the metalloproteinase 7 content in the apical region of principal cells from IS/caput; (iv) reduced in the corpus epididymis, but increased in the efferent ductules, the cadherin 13 mRNA level; (v) reduced testosterone but increased oestradiol levels in the corpus and cauda; (vi) increased the androgen receptor protein content in all regions of the epididymis, and the oestrogen receptor GPER in the corpus and cauda epididymis. In conclusion, treatment with Fulvestrant induced regional-specific changes in hormonal and steroid receptor content, and affected expression of proteins important for epithelial organization and absorption/secretion. The mechanisms of oestrogen action may differ among epididymal regions, which may contribute to determine region-specific sperm functions.
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PMID:Effects of the oestrogen receptor antagonist Fulvestrant on expression of genes that affect organization of the epididymal epithelium. 2478 39


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