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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Luminal fluid was collected by micropuncture techniques from the testis and epididymis of the rat, hamster, rabbit, boar and ram and the concentration of free L-carnitine in the fluid was estimated using enzymic methods. Carnitine was present in the testicular fluid of the rat in concentrations less than 1 mM but increased down the epididymis to reach 53 mM in luminal fluid from the cauda epididymidis, approximately 2000 times higher than in blood plasma. A high concentration was first found in the luminal fluid from the distal caput epididymidis, at about the point where the spermatozoa become motile. Carnitine was also present in the epididymal luminal fluid of the other species studied; the amounts were not as high as those in the rat but were still higher than those in blood plasma.
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PMID:The concentration of carnitine in the luminal fluid of the testis and epididymis of the rat and some other mammals. 46 29

The general histology and ultrastructural features of the developing ductus epididymidis were examined in the brown marsupial mouse, Antechinus stuartii, from April, when males were sexually immature, until August, when the adult males were involved in mating activities, just prior to the annual male die-off. Samples were also examined 3 and 6 months after the August die-off period in males kept in isolation from conspecifics during the prebreeding and breeding periods. In April, tubule diameter and epithelial height were largest in the caput and least in caudal segments but the reverse was observed thereafter. Epithelial height increased in caput segments in August and remained high in the post die-off samples. However, caput epithelial height and tubule diameters were low compared with the remainder of the duct from July until February. Luminal shape in caudal segments (10, 11 and 12) changed in June from circular to a narrow slit, and the epithelium became variable in height. The epididymal epithelium was undifferentiated with few cytoplasmic organelles in April. Differentiation occurred mostly from May to June in association with an increased abundance of cytoplasmic organelles, increasing prostatic weight and rising plasma androgen levels. Differentiated principal and basal cells were found in caput and corpus regions in May and in caudal segments in June in association with the de novo development of a brush border of microvilli. Few clear cells were seen in caput and corpus regions of the duct in May but they, and mitochondria-rich cells, were common throughout the duct from June. Development of the unusual structural features of the cauda epididymidis preceded the arrival of spermatozoa in June. The presence of degenerating spermatozoa and cytoplasmic droplets in the cauda at this time suggested that it was not yet capable of supporting sperm viability. There was no evidence to suggest that the presence of spermatozoa has a stimulatory effect on the epididymis. Intact sperm were observed throughout the duct from July. Free cytoplasmic droplets, which showed some evidence of degeneration, collected in large masses in the distal corpus/proximal cauda epididymidis of adult males between aggregates of spermatozoa. Epididymal differentiation appeared complete by mid-July; few ultrastructural changes occurred after this time. Recruitment of spermatozoa into the epididymis ceased by August and was associated with a rapid decline in sperm content in the proximal caput segments. In the November and February samples, spermatozoa were present only in distal corpus and proximal cauda segments.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Late postnatal development and differentiation of the ductus epididymidis in a dasyurid marsupial (Antechinus stuartii). 141 75

Clusterin is a heterodimeric glycoprotein synthesized and secreted by rat Sertoli cells and epididymal epithelium. The goal of this study was to determine the presence of clusterin in the luminal fluid of the cauda epididymides and its association with the membranes of developing spermatozoa in the presence and absence of androgen. We have previously demonstrated by two-dimensional (2-D) Western blot probing for clusterin that in epididymal fluid the amounts of clusterin were: caput greater than corpus greater than cauda. Luminal fluid from cauda epididymides was collected from control and orchiectomized rats (6 and 12 days) and orchiectomized animals that received testosterone implants. Equal volumes of fluid were analyzed by 2-D Western blot probing for clusterin. Following orchiectomy, there was an increase in clusterin in the luminal fluid after 6 days and maximal amount after 12 days compared with control cauda fluid. Orchiectomized animals which received testosterone treatment showed levels of clusterin comparable to that of controls. Serum clusterin was detected in fluid of orchiectomized animals with and without testosterone. Western blots of cauda sperm membrane extracts of control animals and orchiectomized animals treated with testosterone had a very low level of epididymal clusterin, whereas extracts collected from orchiectomized animals revealed high levels of clusterin. We suggest that, in the normal animal, clusterin is secreted into the lumen of the proximal epididymis where it binds to the sperm membrane. In the distal epididymis, clusterin dissociates from sperm and is processed (proteolysis/endocytosis). We hypothesize that, in the absence of androgen, the processing and regulation of clusterin is disrupted.
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PMID:Clusterin (SGP-2) in epididymal luminal fluid and its association with epididymal spermatozoa in androgen-deprived rats. 151 50

The epididymis of the adult honey possum, Tarsipes rostratus, is enclosed by a heavily pigmented tunica vaginalis and lies with the testis in a prominent prepenile scrotum. It is connected to the testis by a single ductus efferentis and is lined by approximately equal numbers of cuboidal ciliated and principal cells. It is unusual for marsupials in having no well-defined compartments or fibrous septae and in having extensive convolutions of the duct only at the caudal flexure. Three principal functional zones (initial, middle, and terminal segments) were identified in the epididymis, based on epithelial type and ultrastructural evidence of sperm maturation. Luminal diameter increases progressively throughout the tract, and epithelial height variations (from about 2 to 20 microns) are greatest in the terminal segment. The epithelium itself is remarkably low (maximum of 21.6 microns) compared with that seen in the epididymis of other mammals. The thickness of the peritubular smooth muscle coat increases close to the junction of the epididymis and ductus deferens. Sperm concentrations were estimated from counts of sperm nuclei and thus can be no more than approximations. The figures are consistent, however, with a rapid increase in concentration in the initial segment, indicating extensive fluid resorption. Sperm concentrations appear to peak in the distal zone of the terminal segment, although sampling problems and wide variations in count make such a conclusion only tentative. Principal and basal cells are the predominant cell types in the epididymal epithelium. Basal cells are most abundant in the initial and distal middle segment. Principal cells show structural evidence of active exchange with the luminal contents and have abundant apical stereocilia, the structure of which depends on the epididymal zone. Other cell types occur less commonly in the epithelium. Lipid-rich and phagocytic principal cells are restricted to the middle and distal zones of the middle segment, respectively. Clear cells, restricted to the terminal segment, and halo cells were found in very low numbers. As in some other marsupials, principal cells (possibly specialized for this function) selectively remove cytoplasmic droplets and probably other cellular debris from the luminal contents. In Tarsipes, however, this process is not very efficient, and many discarded droplets pass through to the terminal segment where they form large masses of debris associated with aggregates of degenerating spermatozoa.
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PMID:Reproduction in the male honey possum (Tarsipes rostratus: Marsupialia): the epididymis. 379 90

Luminal fluid samples were collected by micropuncture of the seminiferous tubule, rete testis, and defined levels of the epididymal tubule. After removal of spermatozoa by centrifugation, the supernatant fluids were analyzed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and an ultrasensitive silver staining procedure to define the sequential change in protein composition along the excurrent duct system. Fluid from each segment displayed a characteristic 2-D PAGE map composed of numerous polypeptides. Seminiferous tubule fluid contained a wide array of polypeptides, with most concentrated in the 45 Kd to 90 Kd range, but, in contrast, rete testis fluid lacked most of these polypeptides. The major complex of rete testis fluid comigrated with serum albumin and was present in all distal segments. Other major rete testis components were not noted distally. Fluid from the caput was characterized by new major components of 30 to 37 Kd, 28 to 30 Kd, 24 Kd, and 23 Kd, each of which consisted of multiple spots of apparent isoelectric variants; all except the 30 to 37 Kd complex were present in the fluid from more distal segments. Proceeding distally, there was a temporal appearance of new polypeptides, especially in the molecular weight range below 30 Kd. Two-dimensional PAGE analysis of detergent extracts of washed spermatozoa indicate that a specific subset of these fluid polypeptides are sperm associated.
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PMID:Regional differences in luminal fluid polypeptides of the rat testis and epididymis revealed by two-dimensional gel electrophoresis. 397 17

Secretion of p-aminohippurate (PAH) from blood into the sperm-free lumen of the rat cauda epididymidis was studied by a stop-flow luminal perfusion technique. After an intravenous injection of [3H]PAH, radioactive material with chromatographic properties similar to those of free PAH appeared in perfusates. The highest concentration of PAH reached in the lumen was about 3 times that of the free PAH in blood. This was achieved after equilibration of the epididymis with perfusate for 20 min. Luminal accumulation of PAH by the epididymis was inhibited by intravenous injection of probenecid (32 mg/kg). However, deprivation of androgens by castration for 21 days had no effect on secretion. The rate of secretion (from blood to lumen) of PAH altered in a non-linear fashion with the concentration of free PAH in the blood and showed saturation at a free blood concentration of about 4 mumol/l. The apparent Km and Vmax values were 2 mumol PAH/l blood and 0.2 mumol PAH/h. 20 cm tubule, respectively. Based on the concentration profile of PAH across epididymal cells, a model was proposed for the secretion of PAH. It is concluded that the secretory mechanism is similar to that of the renal tubule. The significance of these results was discussed in relation to the functions of spermatozoa in the male reproductive tract.
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PMID:Secretion of p-aminohippurate by the rat epididymis. 403 98

Rats underwent either left unilateral or bilateral vasectomy; the vas deferens was ligated at both ends and a piece of it was removed. 1 animal was sacrificed each week at 1-8 months. Zones I-VI of the epididymis, as described by Reid and Cleland (1957), were studied from both the vasectomized and contralateral sides. When the vasectomized side was compared with the contralateral unoperated side or with controls, no consistent difference was seen in the diameters of the ducts from the various regions of the epididymis (caput, corpus, cauda, and vas). Findings in Zones I-VI are summarized. The vasectomized side had an accumulation of lysosomes and residual bodies in the principal cells; this indicated resorption of spermatozoa. On the contralateral side similar accumulations were seen after 10 weeks. Spermatozoa seem to be first broken down and only then resorbed by the epithelial cells of the epididymal duct. Luminal breakdown of spermatozoa may be due to aging of spermatozoa or a reduced production of certain secretory products by the epididymis. A third possibility, secretion of a lytic substance by the epididymis, is made somewhat untenable by a lack of substantial increase in acid phosphatase levels in the epididymis.
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PMID:Ultrastructural changes in rat epididymis after vasectomy. 473 67

It has been shown that the rat epididymis secretes proteins and organic compounds which may play a role in sperm maturation and storage. A method has been described to study caudal epididymal secretion in anaesthetized rats in vivo. The cauda epididymidis was luminally perfused with Krebs bicarbonate solution. The perfusate collected at the vas deferens was allowed to flow through a microcell and absorption at 280 nm was monitored and displayed on a recorder. Secretion as measured by this method was found to be independent of perfusion rate ranging from 2.8 to 25 microliter/min and was maintained over a period of 8 h. Removal of Na+ ions from the perfusion fluid had no effect on the secretion rate. Removal of Ca2+ by perfusion of the duct with a Ca2+-free EGTA (1.5 mM) solution caused a rise in the secretion rate as revealed by an increase in absorption of the perfusate. High potassium produced similar results. Analysis of the perfusates showed that the Ca2+-free EGTA solution caused an increase in the secretion of non-protein materials whilst high potassium stimulated the release of proteins. Luminal application (0.5 mg/ml) or intraperitoneal injection (30 or 80 mg/kg) of cycloheximide had no effect on secretion during the 6 h post-treatment period. These results are discussed in relation to the possible mechanism of secretion in the epididymis.
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PMID:Effect of intraluminal ion concentrations on the secretion of the rat cauda epididymidis in vivo. 719 Nov 6

The availability of glycerol in the epididymal lumen, and the extent of its utilization by spermatozoa, was studied by measurement of the substrate concentration in epididymal fluid and its oxidation in vitro. The source of luminal glycerol was sought by examining its penetration through the epididymal epithelium of a sperm-free tubule by the technique of luminal perfusion during intravenous infusion of glycerol. [3H]Glycerol was rapidly metabolized to a volatile and mobile molecule that quickly equilibrated between blood plasma and the epididymal lumen and so could not be used to monitor transfer. When blood levels of glycerol were raised by infusion of large amounts of the unlabelled compound, glycerol was detected in epididymal perfusates and a positive linear correlation existed between the rate of secretion into the epididymal lumen and the blood plasma concentration, suggesting that passive diffusion across the epithelium from blood could occur. In normal rats, however, the concentration of glycerol in sperm-free epididymal fluid (1.15 mM) exceeded that in blood plasma (0.35 mM). Luminal glycerol is therefore thought to arise from degradation of epididymal lipid.
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PMID:Entry of glycerol into the rat epididymis and its utilization by epididymal spermatozoa. 745 13

Luminal testicular factors are known to be important for the regulation of the epididymal epithelium. The present study was undertaken to test the hypothesis that complete deprivation of luminal factors by efferent duct ligation (EDL) would induce apoptosis in the epididymal epithelium, as does removal of trophic factors from other cell types. Additionally, experiments were performed to determine whether the apoptosis detected was p53 dependent or independent. Apoptosis detection was by terminal deoxynucleotidyl-mediated deoxyuridine triphosphate-biotin nick-end labeling and by DNA fragmentation studies. EDL caused loss of testicular luminal contribution in zone 1A of the rat epididymis (proximal initial segment) within 6 hr and induced epithelial apoptosis within 12 hr of the efferent duct obstruction. The wave of apoptosis in zone 1A was completed by three days after EDL and was followed by a much smaller wave in zone 1B which peaked three days after EDL. Significant apoptosis was not detected in any epididymal region distal to the initial segment for periods as long as 15 days after EDL. p53, a key apoptotic-pathway molecule in many tissues and conditions was tested by immunohistochemical and Western blot techniques and was not upregulated in the initial segment epithelium within the time cells were undergoing apoptosis and well before the wave of apoptosis was complete. It was concluded that epithelial apoptosis in the initial segment of the rat epididymis is induced by deprivation of luminal testicular factors, is localized to the proximal and middle initial segment, and is p53 independent.
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PMID:p53 independent, region-specific epithelial apoptosis is induced in the rat epididymis by deprivation of luminal factors. 1033 57


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