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

Human epididymal spermatozoa taken from caput, corpus, and cauda were investigated to determine their fertilizing capacity (22 epididymides from 11 patients who had undergone orchidectomy because of prostatic cancer). The following functions, which have been reported to correlate positively with the fertilization rate, were determined: motility and progressive motility, chromatin condensation (assessed by aniline blue staining), acrosin activity, and induction of acrosome reaction by low temperature. In addition, stimulation of motility by pentoxifylline and phosphatidylcholine was examined. The results showed that motility, progressive motility, normal chromatin condensation, and inducible acrosome reaction increased from the caput to the cauda epididymidis, whereas acrosin activity was normal in all sections. Stimulation of progressive motility, especially that of caput spermatozoa, could be achieved by both pentoxifylline and phosphatidylcholine, the latter being definitely superior. In conclusion, our study confirmed that human spermatozoa in physiological status undergo several steps of maturation during the epididymal transit. Stimulation of sperm motility by phosphatidylcholine may be helpful for patients in whom epididymal spermatozoa are used for assisted reproduction.
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PMID:Function of human epididymal spermatozoa. 772 72

A trypsin-like protease was extracted with 1% cetyltrimethylammonium bromide (CTAB) at pH 7.0 from boar cauda epididymal sperm nuclei whose acrosin had previously been removed by acid extraction. The CTAB-extracted sperm protease (CSP) was purified by ion-exchange chromatography on CM-23, gel filtration on Sephadex G-100, affinity chromatography on benzamidine-CH-Sepharose 4B, and HPLC on CM-5PW. CSP is a two chain protein composed of M(r) 2.6K and M(r) 37K chains, which are covalently cross-linked by disulfide bonds. CSP exhibited a pH optimum between pH 8.0 and 9.0, and was inhibited by diisopropyl phosphorofluoridate, antipain, leupeptin, and 1-chloro-3-tosylamide-7-amino-L-2-heptanone. The activity of CSP was enhanced about 1.2-fold with 50 mM CaCl2, with which acrosin is enhanced 2.0-fold. The catalytic efficiency (kcat/Km) of CSP toward Bz-L-Arg-OEt, Tos-L-Arg-OMe, and Tos-L-Lys-OMe in the presence of 50 mM CaCl2 differed from that of acrosin by factors of 0.53, 1.2, and 0.80, respectively. Amino acid sequencing of V8-digested peptides of CSP, and its L- and H-chains showed that the amino acid sequence of CSP was closely related to, but different from, that of acrosin. These results suggest that CSP is a novel acrosin-like enzyme that differs from acrosin in its location in the sperm head, the effect of calcium ions on its activity, and its substrate specificity.
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PMID:Purification and characterization of a novel acrosin-like enzyme from boar cauda epididymal sperm. 782 68

The effects of ingestion of sodium fluoride (NaF), 10 mg/kg body weight for 50 days, on the structure and metabolism of sperm of albino rats (Rattus norvegicus), were investigated. In different groups of rats, the reversible effects upon withdrawal of NaF treatment and by administering some therapeutic agents, viz., ascorbic acid and calcium alone and in combination with NaF (50 and 70 days), on sperm structure and metabolism were also studied. The results revealed that the sperm acrosomal hyaluronidase and acrosin were reduced after 50 days of NaF treatment. Sperm stained with acidic alcoholic silver nitrate revealed acrosomal damage and deflagellation, which might be causative factors for the reduced activity of the enzymes. These alterations also resulted in a decline in sperm motility. The cauda epididymal sperm count was decreased, perhaps because of spermatogenic arrest. Thus, the low sperm motility and count ultimately contributed toward reduction in fertility by NaF treatment. However, withdrawal of NaF treatment for 70 days produced incomplete recovery, while administration of ascorbic acid and calcium, individually and in combination, brought about significant recovery of fluoride-induced effects. Thus, the effects of fluoride on sperm structure and metabolism of rats are transient and reversible.
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PMID:Reversible effects of sodium fluoride ingestion on spermatozoa of the rat. 788 87

Seven independent cross-hybridizing clones have been isolated from a Macaca fascicularis epididymal cDNA library and their inserts shown to correspond to a secreted inhibitor of the sperm serine proteinase, acrosin. Hybridizing transcripts of approx. 0.6 kb have been shown by Northern blot analysis to be considerably more abundant in the epididymis than the testis. This finding is in surprising contrast to a previous report that human acrosin-trypsin inhibitor mRNA predominates in the testis.
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PMID:Sequence analysis of monkey acrosin-trypsin inhibitor transcripts and their abundant expression in the epididymis. 843 54

Protein C inhibitor (PCI) is a heparin-binding plasma serine protease inhibitor that was originally identified as an inhibitor of activated protein C. PCI has a broad protease specificity, inhibiting several proteases in hemostasis and fibrinolysis by acting as a suicide substrate. Recently it has been reported that proteases of the reproductive system, such as acrosin, prostate-specific antigen, and tissue kallikrein, can also be effectively inhibited by PCI. However, a direct relation between PCI and physiological events during fertilization has not yet been established. An attempt was made to monitor and localize the inhibition of the sperm protease acrosin by PCI. Localization experiments for PCI on epididymal spermatozoa showed that PCI is present on the acrosomal cap of human spermatozoa, which demonstrates the early presence of PCI in the male reproductive tract. Induction of the acrosome reaction in ejaculated human spermatozoa resulted in the disappearance of PCI from the plasma membrane overlying the acrosomal head and the appearance of a strict distribution at the equatorial segment of human spermatozoa. The activity of acrosin in sperm extracts could be effectively inhibited by PCI. Zona-binding assays showed that active PCI is able to block sperm-egg binding in a concentration-dependent manner. The combination of the potent inhibition of acrosin and sperm-egg binding by PCI and the localization studies suggested that PCI may protect spermatozoa against premature acrosome reaction and degradation, thereby modulating the acrosin activity so that it can coincide with binding to the oocyte.
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PMID:Protein C inhibitor may modulate human sperm-oocyte interactions. 951 Sep 55

To identify a novel candidate(s) for acrosomal proteins that act on the sperm/egg interaction, a DNA fragment was PCR-amplified from a cDNA library of acrosin-deficient mouse testis and then used as a probe to screen a mouse testis cDNA library. Complementary DNA clones encoding each of two similar but different serine proteases, TESP1 and TESP2, have been identified. The nucleotide sequences of these clones indicate that mouse TESP1 and TESP2 are initially synthesized as preproproteins of 367 and 366 amino acids, respectively. Comparison of the two TESP sequences with those of typical serine proteases suggests that each TESP zymogen is probably converted into a two-chain mature enzyme consisting of light and heavy chains covalently linked by a single pre-existing disulfide bond. The conversion may be accomplished by another protease(s) with a trypsin-like cleavage specificity, since it is unlikely that the mature TESP1 and TESP2 are capable of splitting the Lys-Ile bond between the light and heavy chains. Northern blot analysis of total cellular RNA demonstrates that the TESP1 and TESP2 genes are expressed only in the testis, and the transcripts are abundantly present in the haploid round spermatids. Moreover, immunocytochemical analysis of mouse cauda epididymal sperm using affinity-purified antibodies reveals that these two TESPs are both localized in the sperm acrosome and are released during the acrosome reaction induced by calcium ionophore A23187. These findings provide additional clues for elucidating the mechanisms involved in the sperm/egg interactions, including penetration of the zona pellucida by sperm.
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PMID:Two novel testicular serine proteases, TESP1 and TESP2, are present in the mouse sperm acrosome. 958 71

Acrosin is an acrosomal protease believed to play a major role in fertilization. It is synthesized as an inactive precursor, proacrosin, which is processed via (auto)proteolysis into active form(s). In this paper, comparative studies on the characteristics of acrosin from mouse, boar and human are reported. The mouse proacrosin/acrosin was especially investigated to clarify whether or not the enzyme undergoes modifications during epididymal maturation. Acrosomal extracts from mature and immature mouse spermatozoa, as well as from ejaculated boar and human spermatozoa, were analysed by means of SDS-electrophoresis, Western blot and activity measurements. The studies showed that epididymal maturation produced a shift in the molecular weight of proacrosin. It was also observed that the activation kinetics differ strongly between the three species studied. Human proacrosin showed a constant substrate turnover, acrosin from boar showed sigmoidal activation kinetics and mouse acrosin, either from the caput or the cauda epididymides, showed a rapid decay in activity, suggesting the presence of an endogenous specific inhibitor.
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PMID:Characterization of mouse epididymal acrosin: comparative studies with acrosin from boar and human ejaculated spermatozoa. 967 18

Effects of a combination of medoxy-progesterone acetate (MPA) and dihydrotestosterone (DHT) at a dose of 10 mg + 2 mg/kg, injected, in weekly to rats of proven fertility were investigated with respect to their fertility, sperm and organ functions. This hormonal regimen had no effect in body and organ weights except in the testis. A depletion in sperm reserves in testis and epididymis was noted in addition to a loss of their motility in the later. Alterations in cauda epididymal sperm viability and morphology and reduced levels of superoxide dismutase indicated changes in their plasma membrane permeability. Sperm acrosomal enzymes such as acrosin and hyaluronidase were also affected leading to a loss of their function. Consequently the fertility potential of these rats also impaired after 60 days of hormonal regimen. Testicular biochemical machinery revealed its altered metabolism and regressed spermatogenic activity accounting for its loss of weight. Similarly epididymal physiology also exhibited changes leading to impaired sperm maturation. However, toxicity studies showed no significant variations in liver and blood biochemical profiles indicating non-toxic nature of this combination. All these effects seemed to be transient and reversible upon withdrawal of treatment for 60 and 90 days gradually. Thus, this combination with aromatizable androgen is useful for induction of functional sterility.
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PMID:Endocrine approach to male fertility control by steroid hormone combination in rat Rattus norvegicus L. 983 78

The CRES (cystatin-related epididymal spermatogenic) protein is a member of the cystatin superfamily of cysteine protease inhibitors and exhibits highly restricted expression in the reproductive tract. We have previously shown that CRES protein is present in elongating spermatids in the testis and is synthesized and secreted by the proximal caput epididymal epithelium. The presence of CRES protein in developing germ cells and in the luminal fluid surrounding maturing spermatozoa prompted us to examine whether CRES protein is associated with spermatozoa. In the studies presented, indirect immunofluorescence, immunogold electron microscopy, and Western blot analysis demonstrated that CRES protein is localized in sperm acrosomes and is released during the acrosome reaction. Interestingly, while the 19- and 14-kDa CRES proteins were present in testicular and proximal caput epididymal spermatozoa, the 14-kDa CRES protein was the predominant form present in mid-caput to cauda epididymal spermatozoa. Furthermore, following the ionophore-induced acrosome reaction, CRES protein localization was similar to that of proacrosin/acrosin in that it was detected in the soluble fraction as well as associated with the acrosome-reacted spermatozoa. The presence of CRES protein in the sperm acrosome, a site of high hydrolytic and proteolytic activity, suggests that CRES may play a role in the regulation of intraacrosomal protein processing or may be involved in fertilization.
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PMID:Immunolocalization of CRES (Cystatin-related epididymal spermatogenic) protein in the acrosomes of mouse spermatozoa. 1033 Jan 17

A fraction of acrosomal proteins dispersed during calcium ionophore A23187-induced acrosome reaction was prepared from cauda epididymal sperm of wild-type and acrosin-deficient mice, rat, and hamster. The acrosome-reacted sperm were further extracted by Nonidet P-40 to obtain the detergent-soluble protein fraction. Activities of serine proteases in the two protein fractions were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of gelatin. A mixture of 42- and 41-kDa gelatin-hydrolyzing proteases was found in both fractions of the wild-type mouse sperm, whereas the acrosin-deficient mouse sperm contained the active 42-kDa protease and apparently lacked the activity of the 41-kDa protease. However, exogenous bovine pancreatic trypsin compensated for the absence of acrosin in the protein fractions of the mutant mouse sperm; the gelatin-hydrolyzing activity of the 41-kDa protease appeared when the sperm proteins of the mutant mice were treated with pancreatic trypsin. Two-dimensional polyacrylamide gel electrophoresis revealed that the 42- and 41-kDa proteases were distinguished from acrosin by the isoelectric point and immunoreactivity with affinity-purified antibody against an oligopeptide corresponding to the N-terminal amino acid sequence of mouse proacrosin. Moreover, the gelatin-hydrolyzing proteins corresponding to these two proteases were not detected in rat and hamster sperm, in spite of the treatment of the sperm extracts with pancreatic trypsin, and the total amount of gelatin-hydrolyzing activities in mouse was much smaller than those in rat and hamster. These results may reflect the difference of the serine protease system for the sperm penetration through the egg zona pellucida between mouse and other rodent animals, possibly explaining why the acrosin-deficient mouse sperm are capable of penetrating the zona pellucida.
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PMID:Difference of acrosomal serine protease system between mouse and other rodent sperm. 1044 Aug 45


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