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

Small membranous vesicles, between 25- and 75-nm diameter, were collected by high-speed centrifugation from the ram cauda epididymal fluid and were found to be normal constituents of this fluid and of the seminal plasma. The SDS-PAGE protein pattern of these vesicles was specific and very different from that of the caudal fluid, seminal plasma, sperm extract, and cytoplasmic droplets. After two-dimensional electrophoresis separation and mass spectrometry analysis, several proteins were identified and grouped into i) membrane-linked enzymes, such as dipeptidyl peptidase IV (DPP-IV), neprilysin (NEP), phosphodiesterase-I (E-NPP3), and protein G-beta; ii) vesicle-associated proteins, such as lactadherin (MFEG8-PAS6/7) and vacuolar ATPase; iii) several cytoskeleton-associated proteins, such as actin, ezrin and annexin; and iv) metabolic enzymes. The presence of some of these proteins as well as several different hydrophobic proteins secreted by the epididymis was further confirmed by immunoblotting. These markers showed that the majority of the vesicles originated from the cauda epididymal region. The physical and biochemical characteristics of these vesicles suggest they are the equivalent of the exosomes secreted by several cell types and epithelium. The main membrane-linked proteins of the vesicles were not retrieved in the extract from cauda or ejaculated sperm, suggesting that these vesicles did not fuse with sperm in vivo.
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PMID:Identification, proteomic profiling, and origin of ram epididymal fluid exosome-like vesicles. 1563 28

Neutral endopeptidase (NEP, metallo-endopeptidase EC 3.4.24.11; enkephalinase, neprilysin, CD10, CALLA) represents a major regulator of bioactivity of natriuretic peptides. C-type natriuretic peptide (CNP) is present in high levels in epididymis and seminal plasma. However, detailed expression pattern and CNP-related function of NEP in the epididymis are unknown. Comparison of NEP protein levels in various organs revealed an extremely high expression in human and mouse epididymis. NEP was localized exclusively to apical (luminal) parts of epithelial cells. In man, strong NEP-immunoreactivity was associated with epithelia of efferent ducts and the epididymal duct including stereocilia. Segment-by-segment analysis in mouse revealed a distinct distribution along the epididymal duct. We also found the CNP receptor guanylyl cyclase B (GC-B) in epithelial cells of the epididymal duct. Two different NEP inhibitors decreased CNP degradation and increased CNP/GC-B-induced cGMP production by epididymal membranes, suggesting a functional involvement of NEP. Data indicate an important, previously neglected, role of NEP for regulation of luminal factors in the epididymis and suggest a novel role for CNP/GC-B in the epididymal epithelium, presumably in context of local water balance.
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PMID:Neutral endopeptidase (CD10) is abundantly expressed in the epididymis and localized to a distinct population of epithelial cells--its relevance for CNP degradation. 2409 62

Contractions of the adult epididymal duct are well known in the context of sperm transport. Some reports also describe contractions of the epididymal duct during development, but data about their character, regulation and function are sparse. In the foetal human epididymis we found luminal cells and could identify them as exfoliated epithelial cells originating from the epididymis and not from testis by using antibodies against neutral endopeptidase as an epithelial epididymal duct marker. Exfoliated cells were also found in the epididymal duct after birth. Time-lapse imaging revealed directional transport of luminal cells in the neonatal rat epididymis interrupted by pendular movement. Spontaneous contractions were discovered in the neonatal epididymis and an association between these contractions and the transport of the luminal cells could be observed. Both, transport and spontaneous contractions, were affected significantly by substances known to contract (noradrenaline) or relax (the phosphodiesterase 5 inhibitor sildenafil) smooth muscle cells. Immunohistochemistry showed staining for the proliferation marker proliferating-cell-nuclear-antigen (PCNA) in cells of the ductal lumen of the neonatal rat epididymis indicating the extrusion of cells also during proliferation. Our data showed spontaneous contractions of the immature epididymal duct associated with the transport of exfoliated luminal cells before the first occurrence of sperm cells. Results suggest an important role including both (i) a mechanical place holder function of exfoliated luminal cells (ii) together with a novel idea of organized waste disposal of these cells during development.
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PMID:Contractions transport exfoliated epithelial cells through the neonatal epididymis. 3244 62