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)

The indazole carboxylic acid derivative, tolnidamine, has marked antispermatogenic activity in several animal species. In this study, we assessed the effect of tolnidamine on rat Sertoli cell function both in vivo and in vitro, using androgen binding protein (rABP) as a marker. Groups of six male rats were killed 2, 4, 8, 16, 32, 64 hours and 5, 8, and 12 days following tolnidamine administration (250 mg/kg by oral gavage). There was a progressive reduction in both testicular and epididymal weights. Serum FSH levels did not change and LH showed a transient increase between 64 hours and 8 days. Except for an initial increase at 2 hours, there were no changes in serum testosterone. Epididymal rABP concentration and content declined as early as 8 hours, with the lowest values occurring at 5 and 12 days. By 16 hours, there was an increase in testicular rABP, which was also evident at 8 days and 12 days. Within 16 hours after tolnidamine, there was a rise in serum rABP, which persisted until the end of the experiment. When another indazole carboxylic acid derivative, lonidamine, was administered (250 mg/kg), similar changes were evident in epididymal and serum rABP at 32 hours, but the rapid decrease in testicular rABP suggested a different mechanism of action. In another experiment, single oral doses of tolnidamine (50, 100, 250, and 500 mg/kg) were administered to other groups of rats and the animals were killed after 24 hours and 5 days. With increasing doses of tolnidamine, there was a reduction in epididymal rABP concomitant with an increase in testis and serum rABP levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effects of the indazole carboxylic acid derivative, tolnidamine, on testicular function: I. Early changes in androgen binding protein secretion in the rat. 392 32

The annual reproductive cycle of the male little brown bat, in contrast to seasonal reproductive patterns of other mammals, is differentiated by an asynchronous recrudescence of the testis and the accessory reproductive glands. Spermatogenesis occurs during the summer, whereas fully stimulated accessory organs, stored epididymal spermatozoa, and sexual behavior are expressed later during a mating period that extends, albeit interrupted by hibernation, from late summer until early spring. To investigate whether changes in high affinity androgen-binding activity in the circulation are related to the delayed renewal of the accessory organs, plasma sex steroid-binding protein (SBP) and total testosterone (T) levels were measured throughout the year. From these data and determinations of association constants for T binding to SBP and albumin at both hibernating (4 degrees C) and active (40 degrees C) temperatures, estimates of the unbound ("free") and albumin-bound T fractions were made and correlated with changes in the accessory reproductive organs. Plasma SBP concentrations (mean +/- SEM) exhibited wide seasonal fluctuations: they were baseline in May (10 +/- 2 nM) following spring arousal, increased dramatically in June (184 +/- 24 nM), and reached peak levels in early July (262 +/- 29 nM), where they remained until August. In late August they began to fall (104 +/- 23 nM) and then returned to baseline during the hibernation period (October-April). Although total T levels were also elevated in June, it appeared that the unbound ("free") and the unbound plus albumin-bound T fractions did not increase until late July. Since the accessory gland weights did not begin to increase until late July as well, it was concluded that increases in the unbound and albumin-bound T fractions may be an important factor in the recrudescence of the accessories and that increased SBP activity in early summer may play a role in the regression and delayed renewal of these organs. However, what factor(s) maintain the accessory glands, epididymal spermatozoa, and sexual behavior during the breeding and hibernation periods when all T fractions were low are, as yet, undetermined.
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PMID:Annual variations in plasma sex steroid-binding protein and testosterone concentrations in the adult male little brown bat: relation to the asynchronous recrudescence of the testis and accessory reproductive organs. 407 6

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

Rats were made bilaterally cryptorchid at 17 days of age and bilateral orchidopexy performed at 34 days of age. The epididymal content of androgen binding protein (ABP), the weight and morphology of the testis, the cross-sectional area of seminiferous tubules and the testicular concentration of testosterone were then studied at 34, 42, 59 and 120 days of age. Cryptorchidism was followed rapidly by progressive inhibition of spermatogenesis and testicular growth as well as by decreased Sertoli cell secretion of ABP. Orchidopexy resulted in a gradual restoration of spermatogenesis, and all impaired parameters seemed to improve at the same, fairly slow rate. Restoration was not complete, but by 120 days of age the morphological appearance of the testis was compatible with recovery of normal fertility.
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PMID:Maturation of the juvenile rat testis after surgical treatment of cryptorchidism. 614 37

In the rat, the effects of progestin and androgen administration on serum, testicular and epididymal androgen binding protein (rABP) concentrations were determined and related to the organ weight and morphology. Adult rats were treated with medroxyprogesterone acetate (MPA; 17 alpha-acetoxy-6 alpha-methylprogesterone), testosterone propionate (TP) and mibolerone (MB; 7 alpha, 17 alpha-dimethyl-19-nortestosterone). MPA reduced testicular and epididymal weights and the concentrations of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone. During MPA treatment testicular and epididymal ABP content declined in parallel with organ weights and hormone concentrations, whereas serum ABP concentrations increased. Combinations of MPA and TP reduced testicular and epididymal ABP, but the reductions were less than with MPA alone; this combined treatment also elevated serum AMP. Both MB and TP reduced ABP in the male reproductive tract, but unlike MPA did not increase the concentration of this protein in serum. The results suggest that MPA acts directly on Sertoli cells resulting in increased ABP release into the blood. The comparison was made of steady state polyacrylamide gel electrophoresis (SS-PAGE) and radioimmunoassay (RIA) methods of estimating rABP. The potency ratio of testicular ABP estimated by the two methods (RIA:SS-PAGE) was three times higher than this ratio in the epididymis in normal and hormonally treated animals. Due to differences in end points, these observations imply that these assays do not quantify the molecules in the same way in one or both of these tissues. The results indicate, however, that both assays are suitable for following rABP concentration in animals with altered hormonal states.
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PMID:Medroxyprogesterone acetate has opposite effects on the androgen binding protein concentrations in serum and epididymis. 622 25

Male rats treated with a single injection of antiserum to LHRH (LHRH-AS) at 5 days of age have small testes as adults. In the present investigation, the serial maturation of the hypothalamic-pituitary-gonadal axis was studied in young male rats passively immunized with LHRH-AS. Testicular and epididymal weights, serum androgen and gonadotropin levels, testicular receptors for human CG (hCG), and androgen binding protein (ABP) concentrations in serum, testis, and epididymis were compared in developing animals treated with a single ip injection of LHRH-AS or normal rabbit serum. Rats treated with LHRH-AS had lower serum concentrations of ABP at all ages; the highest levels were on days 22-24, which were several days later than controls. Testicular weight was about 60% that of the control at all ages from 10-90 days. A reduction in epididymal weight to 80% that of the control was seen only in adults at days 60 and 90. Testicular ABP content increased steadily with age, but its concentration peaked at day 17 for controls and day 22 for LHRH-AS treated animals. Both testicular and epididymal ABP content were commensurate with testicular weight in controls and treated rats through day 45. Similarly, hCG-receptor content and concentration increased steadily with age, but differences between control and treated groups paralleled testicular weight. These results suggest an effect of LHRH blockade at a critical period which impairs early testicular growth and causes a permanent reduction in growth. Sertoli cell function and hCG-receptor appearance are impaired in proportion to this reduction.
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PMID:Sertoli cell maturation is impaired by neonatal passive immunization with antiserum to luteinizing hormone-releasing hormone. 640 17

Concentrations of sex steroid-binding protein (SBP) in plasma of immature male little brown bats (Myotis lucifugus lucifugus) were found to be low (15 +/- 2.8 (S.E.M) nmol/l) and stable throughout the period of hibernation which immediately precedes the onset of the first spermatogenic cycle (sexual maturity). In contrast, plasma SBP titres in spermatogenically active adults (summer) were markedly raised (238 +/- 26 nmol/l). When immature males were removed from hibernation and maintained on a long photoperiod of 16 h light: 8 h darkness at a constant temperature of 25 degrees C to accelerate the onset of sexual maturity, these animals exhibited a rapid rise in circulating SBP. Plasma levels of SBP in immature males maintained on a long photoperiod increased significantly after 2 weeks, and by 3 weeks reached values (234 +/- 20 nmol/l) that were indistinguishable from those seen in spermatogenically active adults. These high plasma SBP titres at 3 weeks were accompanied by increases in testicular and epididymal weights and the onset of spermatogenesis. However, no stimulation of the sex accessory glands was observed, possibly reflecting the effects of increased plasma SBP on the biological activity of circulating androgens. The ability of immature male Myotis to exhibit a pubertal increase in plasma SBP following simple environmental manipulation should provide a valuable model for the study of the control and action of sex steroid-binding protein.
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PMID:Control of plasma sex steroid-binding protein in the bat Myotis lucifugus lucifugus: induction of steroid-binding activity in immature males. 640 7

This study was designed to determine the effects of a short episode of testicular heating (43 degrees C for 15 min) on spermatogenesis and Sertoli and Leydig cell function. Rats killed at intervals up to 156 days after heating were assessed by histological examination, and by measurement of serum FSH and LH, and by tests of Sertoli cell function consisting of fluid production, androgen binding protein (ABP) content of the ligated and unligated tests, together with the binding of [125I]FSH. Leydig cell function was assessed by in vitro testosterone production, serum testosterone levels and [125I]hCG binding to testes homogenates. Testis weight declined 7 days after heating to 70% of control and remained lower until 82 days, whereas epididymal weight did not decrease significantly until 26 days and also recovered by 82 days. Fluid production was significantly lower in heated testes at 26 days and returned to normal at 56 days. ABP production measured as the difference between the ABP content of ligated and unligated testes was significantly reduced at 14 and 26 days, but subsequently recovered. Serum FSH levels were significantly elevated from 14-26 days in the heat treated group and the binding of [125I]FSH was reduced at 26 days post-heating. Basal and stimulated in vitro T production was significantly increased in the heat-treated testes at 14 days and subsequently returned to normal whilst [125I]hCG binding was significantly lower in the heat-treated testes from 7-26 days. Serum T and LH did not alter significantly during the study. Primary spermatocytes and young spermatids were the most heat sensitive germ cell type and a reduction in spermatogenesis was noted from 7 to 26 days, although recovery appeared complete by 56 days and thereafter. These results demonstrate that the transient spermatogenic disruption induced by heating is accompanied by significant alterations in Sertoli and Leydig cell function which are identical to those produced in other models of spermatogenic dysfunction. The results suggest that the duration of these changes appears to correlate closely with alterations occurring in the germ cell compartment.
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PMID:Changes in testicular function induced by short-term exposure of the rat testis to heat: further evidence for interaction of germ cells, Sertoli cells and Leydig cells. 643 36

The effects of estradiol-17 beta on androgen uptake, metabolism and binding were studied in rat epididymis in vivo in comparison with cyproterone acetate. Steroids (250 ug/100 g body weight) were injected 5 min prior to 3H-testosterone in castrate rats. Estradiol-17 beta inhibited 3H-testosterone uptake into epididymal cytosol by 58% as compared to 38% by cyproterone acetate. 3H-Testosterone uptake into epididymal nuclei was inhibited 95% by estradiol-17 beta and 83% by cyproterone acetate. Total bound radioactivity in cytosol fractions was reduced to a greater extent by estradiol-17 beta than cyproterone acetate when either 3H-testosterone or 3H-dihydrotestosterone was injected. Binding of 3H-dihydrotestosterone to nuclear receptors was completely abolished by estradiol-17 beta; whereas approximately 20% binding remained in the nuclear extract after cyproterone acetate treatment. Metabolism of 3H-testosterone in vivo was also altered by estradiol-17 beta, resulting in diminished conversion to 3H-dihydrotestosterone. Cyproterone acetate, on the other hand, did not affect 3H-testosterone metabolism. Estradiol-17 beta and cyproterone acetate inhibited in vitro binding of 3H-dihydrotestosterone to the intracellular cytoplasmic receptor, but not the intraluminal androgen binding protein (ABP). These data suggest that estradiol-17 beta may have a more potent antiandrogenic effect on the epididymis than cyproterone acetate due to inhibition of 5 alpha reduction of testosterone as well as binding to the androgen receptor.
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PMID:Estradiol-17 beta inhibition of androgen uptake, metabolism and binding in epididymis of adult male rats in vivo: a comparison with cyproterone acetate. 645 38

Rabbit epididymal androgen binding protein (rbABP) and serum testosterone estradiol binding globulin (rbTeBG) were purified and their physicochemical properties compared. Both proteins bound dihydrotestosterone (DHT) with high affinity. Both contained two components, Heavy (H) and Light (L), and their molecular weights and pI values were comparable. rbABP and rbTeBG were different with regard to their ConA-Sepharose binding property. rbABP was not bound by ConA-Sepharose while rbTeBG was found and retained by this lectin; thus, rbABP and rbTeBG differed in their carbohydrate structure. Peptide mapping on SDS-PAGE indicated that the H components of rbABP and rbTeBG were distinct even though they showed a high degree of homology. By contrast, the L components of these two proteins appeared to be identical. The structure of the steroid binding sites of these two proteins was analyzed by peptide mapping of [1,2(3)H]17 beta hydroxy-androsta-4,6-dien-3-one photoaffinity labeled protein. The size distribution of radioactive peptide fragments generated appeared to be identical for these two proteins. However, the distribution of labeled peptides was slightly different when examined by high pressure liquid chromatography (HPLC). The observations suggest that the differences between rbABP and rbTeBG might reside not only in carbohydrate moieties but also in their amino acid sequences.
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PMID:Comparison of rabbit androgen binding protein with testosterone estradiol binding globulin--I. Physical and chemical properties. 654 37


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