Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study demonstrates that beta-glucuronidase from rat preputial glands binds with high affinity to spermatozoa from the cauda epididymis. The binding was calcium-independent and was inhibited by mannose-6-phosphate, but not by other phosphorylated or non-phosphorylated sugars. Binding was also inhibited by alpha-mannosidase from Dictyostelium discoideum, an enzyme known to have mannose-6-phosphate as the ligand. From solubilized sperm membranes, a protein of > 200 kDa and one of 45 kDa, were absorbed to a column of D. discoideum enzyme and to a phosphomannan column respectively, and eluted with mannose-6-phosphate. According to histochemical observations at the light and the electron microscopic level, gold particles coated with the enzyme became bound to the external surface of the plasmalemma in the acrosomal region of caudal spermatozoa. Similar labelling was observed using gold particles coated with antibodies against the rat 300 kDa phosphomannosyl receptor. The existence of phosphomannosyl receptors on the sperm plasma membrane, and our previous demonstration of the presence of affinity sites for epididymal beta-galactosidase on these gametes which is inhibited by phosphofructosyl derivatives, suggest strongly that maturing spermatozoa could be a target for glycosidases secreted into the lumen of the cauda epididymis, which then become bound to these cells via different ligand-receptor systems.
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PMID:Phosphomannosyl receptors on the surface of spermatozoa from the cauda epididymis of the rat. 755 73

Glycosidases secreted by the epididymis become bound to the surface of spermatozoa during their transit through the epididymal duct. They are believed to play a role in mammalian fertilization. In the present report, we demonstrate that beta-glucuronidase binds to the surface of ejaculated human spermatozoa with high affinity and in a saturable manner. The binding is Ca(2+)-independent, inhibited by either mannose-6-phosphate, phosphomannan fragments from the yeast Hansenula holstii and alpha-mannosidase from the Dictyostelium discoideum, suggesting that phosphomannosyl receptors are involved in the recognition of the enzyme. The catalytic site of the enzyme is not involved in the binding. The localization of the beta-glucuronidase binding-sites is restricted to the surface of the sperm head. These results suggest that the spermatozoa could be the target for glycosidases present in the seminal plasma.
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PMID:Affinity sites for beta-glucuronidase on the surface of human spermatozoa. 902 Oct 45

Intrauterine fluid (IUF) was collected using a tampon from mid-oestrous mares (n = 57) with and without ultrasonically detectable accumulations of free intraluminal fluid. Bacteria were cultured and neutrophils counted from all samples (n = 57). Total protein concentration, trypsin-inhibitor capacity (TIC), and plasmin, beta-glucuronidase (B-Gase) and N-acetyl-beta-D-glucosaminidase (NAGase) activities were determined in 27 IUF samples. The motility of spermatozoa in the presence of IUF, IUF extended with Kenney's medium (1:1) and Kenney's medium alone was analysed in 9 samples using a Hamilton-Thorn motility analyser. Thirty-five mares were inseminated immediately after collection of IUF, and every second day until ovulation. Embryos were recovered nonsurgically 6 days after ovulation. After embryo transfer, fluid accumulations were recorded during oestrus and an endometrial biopsy specimen taken (n = 53). In the beginning of oestrus, fluid accumulations were detected in 39% (22/57) of mares, while on the day when IUF was collected, fluid accumulations were observed in 26% (15/57) of mares. The fluid was anechogenic, and in 80% of the mares located in the uterine body. None of the mares exhibited cytological or bacteriological evidence of acute endometritis. Total protein concentrations, TIC and B-Gase activities in IUF were statistically significantly lower in mares with fluid accumulations (n = 14) than in mares without fluid accumulations (n = 13) (p < 0.01). The addition of undiluted IUF to extended semen significantly reduced total and progressive motilities, path velocities and percentages of rapid spermatozoa (p < 0.05) in vitro. On endometrial biopsy, fibrosis was found to be more prominent (p = 0.025) in mares with fluid accumulations (n = 9) than in mares without (n = 44). It was concluded that anechogenic fluid accumulations during oestrus were associated with compositional changes in IUF. Although IUF had negative effects on spermatozoal motility in vitro, the presence of fluid accumulations at the time of insemination did not affect embryo recovery rates.
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PMID:Intrauterine fluid accumulation in oestrous mares. 912 48

Spermatozoa released from the seminiferous tubules are terminally differentiated cells with no known synthetic activity. Their components are synthesized in the spermatogenic cells during spermatogenesis. In this study, we report the characterization and immunolocalization of beta-glucuronidase in mouse testicular germ cells and spermatozoa. The enzyme is an exoglycohydrolase with dual localization, being present in lysosomes and endoplasmic reticulum of several mouse and rat tissues. The purified germ cell preparations (spermatocytes, round spermatids, and condensed/elongated spermatids) when assayed for beta-glucuronidase activity showed that the spermatocytes contained five times more enzyme activity per cell than the spermatids. Polyacrylamide gel electrophoresis, carried out under native and denaturing conditions, demonstrated that the germ cells express only the lysosomal form of the enzyme (pI 5.5-6.0) with a subunit molecular mass of 74 kDa. Immunocytochemical studies revealed a positive reaction in the Golgi membranes, Golgi-associated vesicles, and lysosomes of late spermatocytes (pachytene spermatocytes) and a stage-specific localization during spermiogenesis. The forming or formed acrosome of the elongated spermatids (stages 9-16) and epididymal spermatozoa was highly immunopositive. Comparison of immunoprecipitation curves and kinetic properties of the enzyme present in spermatocytes and spermatozoa revealed no major differences. Taken together, our results demonstrate that beta-glucuronidase activities present in the lysosomes of spermatocytes and the sperm acrosome are kinetically and immunologically similar.
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PMID:Characterization and immunolocalization of beta-D-glucuronidase in mouse testicular germ cells and spermatozoa. 1004 47

The human epididymis and its secretions actively promote sperm fertilizing capacity and provide protection for spermatozoa against harmful influences. Among epididymal secretions, glycosidases have been recently studied and associated with molecular changes on the sperm surface. In the present work, we studied the influence of different concentrations of testosterone, dihydrotestosterone and cyproterone acetate on the secretion of alpha-glucosidase, N-acetyl-glucosaminidase, beta-glucuronidase and alpha-mannosidase by isolated and cultured epithelial cells from human caput, corpus and cauda epididymides. Cell cultures were obtained from aggregates of isolated tubule fragments plated on extracellular matrix-covered multi-well plates. Activities of the glycosidases were measured in conditioned culture media and were higher in the distal regions of the epididymis. Testosterone and dihydrotestosterone significantly increase the enzyme secretion in a concentration-dependent manner. This increase was higher in corpus and/or cauda than in caput epididymis. Cyproterone acetate caused a dose-dependent decrease in glycosidase secretion in cultures from all epididymal regions. It is concluded that the secretion of epididymal glycosidases is regulated by androgen, being stimulated by dihydrotestosterone and testosterone and inhibited by the androgen antagonist cyproterone acetate.
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PMID:Androgen regulation of glycosidase secretion in epithelial cell cultures from human epididymis. 1035 69

The activities of acid beta-glucuronidase, alpha-mannosidase, alpha-glucosidase, alpha-galactosidase, beta-galactosidase and beta-N-acetylglucosaminidase were analysed in seminal plasma and spermatozoa from 26 infertile men with varicocele and from 36 men of normal fertility. Semen samples from ten men with non-obstructive azoospermia were used as control specimens that contained the other components of semen. Spermatozoa were solubilized by both physical (homogenization) and chemical (Triton-X100) methods to obtain the soluble and non-soluble fractions. The activities of several glycosidases measured both in seminal plasma and spermatozoa were directly correlated with the numbers of spermatozoa and sperm motility, confirming previous studies. As some infertile patients with varicocele have normal semen parameters, whereas others have low numbers of spermatozoa and low sperm motility, the varicocele patients were prospectively divided into two groups: one (n = 15) with normal spermiograms and the other (n = 11) with abnormal spermiograms. The activities (expressed in mU ml(-1)) of alpha-mannosidase, beta-galactosidase and beta-N-acetylglucosaminidase in seminal plasma of normozoospermic infertile patients with varicocele were significantly higher than those of fertile controls, but not when expressed in U per 10(8) spermatozoa. The activities of beta-glucuronidase, alpha-mannosidase, beta-galactosidase and beta-N-acetylglucosaminidase in seminal plasma when expressed in U per 10(8) spermatozoa in varicocele patients with abnormal spermiograms were significantly higher than in those of men of normal fertility. The activity of alpha-mannosidase in the soluble fraction of sperm homogenates, expressed as U per 10(8) spermatozoa, was significantly higher in infertile patients with varicocele and abnormal spermiograms than in controls. In the non-soluble fraction of spermatozoa from infertile patients with varicocele, there was an increase in the expression of beta-galactosidase and beta-N-acetylglucosaminidase activities compared with the fraction of spermatozoa from fertile subjects. In summary, infertile patients with varicocele displayed an overexpression of acid alpha-mannosidase, beta-galactosidase and beta-N-acetylglucosaminidase activities in seminal plasma and spermatozoa that may be associated with functional defects in spermatozoa as these glycosidases play an important role in mammalian fertilization.
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PMID:Abnormal expression of acid glycosidases in seminal plasma and spermatozoa from infertile men with varicocele. 1188 18

The mammalian epididymis is an organ particularly rich in acid hydrolases, consistent with a developed lysosomal apparatus. However, some of these enzymes could also play a role in an extracellular environment, since they are actively secreted by the epithelium. In this study the authors measured the activity of five acid hydrolases distributed between the epithelium, fluid, small vesicles, and spermatozoa of the rat cauda epididymis in adult rats, and compared with that distribution under conditions of deprivation of luminal testosterone and testicular compounds (hemicastration). Lysosomal enzymes are differently compartmentalized in rat cauda epididymis. Most of beta-galactosidase (beta-GAL) and aryl sulfatase (approximately 70%) were found in soluble form within the fluid. Some 60% of N-acetyl-beta-D-glucosaminidase (beta-NAG) and alpha-mannosidase (alpha-MAN) become transiently bound to sperm, and beta-glucuronidase (beta-GLU) was mostly concentrated in the epithelium. After remotion of testis this distribution changed, as the retention of alpha-MAN, beta-GAL, beta-GLU, and beta-NAG by the epididiymal tissue increased. The increase of beta-GLU followed an increase of synthesis of the enzyme. The distribution of enzymes in the epididymis from the contralateral side was similar to that in normal rats. The different roles for each enzyme in the epididymis are discussed.
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PMID:Compartmentalization of lysosomal enzymes in cauda epididymis of normal and castrated rats. 1196 12

Pregnancy rates after frozen semen inseminations (AI), particularly in older and problem mares, are lower than after fresh semen AI. Uterine contractility and the inflammatory reaction after frozen semen insemination were studied in two groups of mares: the abnormal group comprised of 6 old barren mares categorized in biopsy category IIB or III, and the control group including 6 reproductively normal young maiden mares in biopsy category I or IIA. All 12 mares were inseminated in the first cycle with 2 mL of phosphate-buffered saline (PBS) and in their second cycle with 2 mL of frozen semen containing 800 x 10(6) spermatozoa. Before and 1, 2, 4, 8, and 20 to 24 h after this treatment, all mares were examined by ultrasonography for intrauterine fluid accumulations (IUFA). The examinations were videotaped to count the number of uterine contractions later. Uterine fluid was obtained by tampon before treatment, and by the tampon method followed by uterine lavage after the last examination. Fluids were cultured bacteriologically, and polymorphonuclear leukocytes (PMN) were counted. Trypsin-inhibitor capacity (TIC), lysozyme concentration, and beta-glucuronidase (BGase) and N-acetyl-beta-D-glucosaminidase (NAGase) activities were determined in frozen-thawed tampon and lavage fluids. Both treatments induced significant neutrophilia in the uterine lumen. Although PMN concentrations were numerically higher after frozen semen AI than after PBS-treatment, the difference was not significant. There was not any difference between the mare groups either. The amount of IUFA differed only in the normal group between frozen semen AI and PBS treatment, and between 0- and 24-h samples for frozen semen AI. Although abnormal mares showed consistently more fluid than normal mares, this difference was not significant. Uterine contractions and enzyme concentrations between groups did not differ. None of the variables showed significant differences between the normal and abnormal mares in their reaction to frozen semen AI.
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PMID:Effect of frozen semen on the uterus of mares with pathological uterine changes. 1546 Jan 63


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