Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A major secretory protein of the human epididymis that is taken up by maturing spermatozoa is homologous to the leukocyte antigen CD52. The epididymis was shown to be the sole source of CD52 in seminal fluid, since CD52 could be detected in seminal plasma from sperm-containing ejaculates and not in ejaculates of vasectomized patients by Western blot analysis. The glycoprotein is not expressed in the testes. A fluorescence immunobinding assay was developed to quantify the amount of epididymal secretion of CD52 in the seminal plasma of various groups of fertile and infertile patients. Donor spermatozoa bearing CD52 were used as binding site tracers for free anti-CD52 antibody remaining after it had adsorbed CD52 from the seminal plasma to be assayed. The level of subsequent antibody binding to spermatozoa was measured by flow cytometry and the extent of binding inhibition was compared to a reference pool of seminal plasma to provide relative amounts of CD52 in test seminal plasma. There were no correlations between seminal plasma CD52 concentration and any semen parameter tested, including sperm concentration, percentage motility, normal sperm morphology or the concentration of seminal neutral alpha-glucosidase, fructose and zinc. There was a slight tendency towards an inverse relationship with the amount of CD52 on spermatozoa, but this was not significant. No differences were found among groups of patients classified by their semen parameters or fertility status. These findings indicate that the epididymal specific supply of CD52 is not a limiting factor for CD52 uptake onto spermatozoa.
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PMID:Epididymal secretion of CD52 as measured in human seminal plasma by a fluorescence immunoassay. 966 31

The origin of seminal leucocytes and their biological significance were investigated in 76 whole ejaculate samples and 27 split ejaculate samples, obtained from patients attending the Zimbabwe Family Planning Council's Spilhaus Infertility Clinic at Harare. The leucocytes were more prevalent in fractions 1 and 2 than in fraction 3, implying that the testis, epididymis and prostate are the major sources of seminal leucocytes. The contribution from the seminal vesicles was minimal. An inverse relation is apparent between leucocyte count and sperm count (p < 0.01). The percentage of abnormal sperms was higher (p < 0.05) and the sperm motility poorer in leucocytospermic samples (p < 0.01). Fructose, the seminal vesicular marker, citric acid, the prostatic marker and alpha-glucosidase, the epididymal marker were not decreased in leucocytospermia. It is concluded that the epididymis and prostate are the major contributors of granulocytes in semen. Leucocytospermia affects sperm morphology and sperm motility but not the accessory sex gland functions. Probably these cytotoxic effects are mediated by hydrogen peroxide due to activation of seminal leucocytes. However, the presence of leucocytospermia in normozoospermic samples is indicative of the possible peaceful coexistence of leucocytes and sperms.
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PMID:Study on the origin of seminal leucocytes using split ejaculate technique and the effect of leucocytospermia on sperm characteristics. 987 48

Results from recent animal models with implications for putative human male contraceptives acting on the epididymis are reviewed. Inducing sterility by enhancing sperm transport through the epididymis has not been achieved. The induction of infertility in males of several species is easier to achieve by direct actions of drugs on sperm function (e.g. inhibition of sperm-specific isoenzymes of the glycolytic pathway by chloro-compounds) than by indirectly reducing amounts of epididymal secretions normally present in high concentration (e.g. alpha-glucosidase, L-carnitine). The former show promise for the clinic since human spermatozoa are susceptible to inhibition. On the other hand, the infertile male mice of the c-ros knock-out model demonstrate the influence of even a small region of the epididymis on fertility, so that targeting the as yet unknown epididymal factors presumably secreted in limiting amounts by this epididymal segment, is a new lead for a contraceptive. Targeting a specific sperm protein acquired in the testis, but depleted in the epididymis by toxicants that induce rapid infertility, may also lead to the discovery of new contraceptives, but these will require developing new means of organ-specific delivery of contraceptive drugs.
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PMID:Recent biochemical approaches to post-testicular, epididymal contraception. 1033 18

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

alpha-Glucosidase is a normal constituent of human semen, produced mainly in the epididymis. It is significantly correlated to sperm count. Its activity is low in cases of epididymal obstruction. We evaluated alpha-glucosidase activity in 653 semen samples of patients, who attended our department for marital infertility, with respect to associations to clinical and other seminal parameters. The normal range (mean +/- 2 SD) in samples with normal parameter values was 7.2-46.4 mU ml-1. The determination in patients with azoospermia revealed mean values of 7.7 +/- 9.5 mU ml-1 in obstructive azoospermia, and 15.8 +/- 11.5 mU ml-1 in nonobstructive azoospermia. The difference was not statistically significant in that the sensitivity of determination with respect to the presence of obstruction was only 0.66, and the specificity 0.83. A significant correlation (r = 0.34) of alpha-glucosidase activity with log sperm count was observed. The mean alpha-glucosidase activity was not significantly different in groups formed according to sperm motility, according to leucocyte count or according to semen volume. A difference between smokers and nonsmokers with comparable sperm count, as reported in the literature, did not occur. We conclude from our results that the determination of alpha-glucosidase activity does not give additional information of the fertility status exceeding that of other clinical investigations or parameters of semen analysis.
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PMID:Why do we determine alpha-glucosidase activity in human semen during infertility work-up? 1052 38

The effects of atrazine exposure on testicular sperm number, epididymal sperm number and motility and alpha-glucosidase activity in the epididymis were studied in Fischer rats. Histological changes in the testicular tissue were followed by light and electron microscopy. Groups of adult animals were treated i.p. with 60 and 120 mg atrazine kg(-1) body wt. twice a week over 60 days. The results indicate a decrease in the body weight and relative weights of pituitary and ventral prostate vs control, measured on the last day of treatment in both treated groups. Testicular sperm number (expressed as number of sperm per 500 Sertoli cells) in atrazine-treated groups increased with the treatment time due to the reduced sperm motility. Therefore atrazine treatment provoked a significant decrease in sperm number and motility in epididymis, measured after the last day of treatment. alpha-Glucosidase activity in the epididymis, after the last day of treatment, showed a decrease in both treated groups vs control values. Histological analysis of testicular tissue from treated rats showed the cell disorganization and cell clusters together with spermatocytes. Electron microscopy presented differently vacuolated cytoplasm, collagen fibre was reduced, Leydig cells were of irregular shape with unequal form and cisternae of rough endoplasmic reticulum were accentuated and softly widened. In Sertoli cell cytoplasm, atrazine treatment provoked degenerative changes. According to the results obtained, it is evident that atrazine exerted morphological changes and a toxic effect on sperm and their motility.
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PMID:Disorders of male rat reproductive tract under the influence of atrazine. 1064 Oct 17

The seminal plasma components neutral alpha-glucosidase, carnitine, fructose, citrate, and polymorphonuclear granulocyte (PMN) elastase in 253 men were determined. The seminal plasma of 221 infertile men, a control group with proved fertility and 13 patients after vasectomy were investigated. The concentrations of free carnitine (212 versus 521 micromol/l, n = 219, P < 0.001), total carnitine (437 versus 743 micromol/l, n = 219, P < 0.001), and the activity of neutral alpha-glucosidase (15.1 versus 23.4 IU/l, n = 236, P < 0.05) were significantly reduced in the infertile patient group as compared to the fertile control group, the concentration of PMN elastase (102 versus 48 microg/l, n = 234, P < 0.05) being significantly increased in the infertile patients. In the patients after vasectomy the activity of neutral alpha-glucosidase was the only epididymal marker that was significantly reduced (4.3 versus 9. 8 IU/l, n = 35, P = 0.002) in comparison with the patients with testicular azoospermia. At a limit of 6 IU/l the sensitivity of the method was 92% and the specificity was 72%. Altogether, the epididymal markers were reduced in subfertile patients compared with the control group. For the differential diagnosis of azoospermia only the determination of the neutral alpha-glucosidase activity is useful.
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PMID:Relationship between semen quality and the seminal plasma components carnitine, alpha-glucosidase, fructose, citrate and granulocyte elastase in infertile men compared with a normal population. 1073 29

The dynamics of glycosidase secretion was evaluated in human epididymal cell culture. Epithelial cells from caput, corpus, and cauda epididymis were isolated from tissue obtained from patients undergoing therapeutic orchidectomy due to prostatic carcinoma. The activities of alpha-glucosidase, N-acetylglucosaminidase, beta-glucuronidase, and alpha-mannosidase were analyzed in conditioned culture media. Glycosidase activity was significantly higher in corpus and/or cauda than in caput epididymis. There was a time-dependent increase in enzyme activities that was maximal between 10 and 14 days of culture in all epididymal regions. Epididymal glycosidases are secreted by cultured epithelial cell from human epididymis with an increase toward the distal regions of this organ, which may be related to the dynamics of sperm maturation. Cultures from different epididymal regions may represent a valuable tool to study of human epididymal function.
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PMID:Secretion of glycosidases in human epididymal cell cultures. 1095 1

The induction of infertility in males of several species through epididymal interference is more difficult to achieve by reduction of the amounts of epididymal secretions (eg alpha-glucosidase, L-carnitine) or immunological interference with secreted proteins (eg D/E, P34H, P26h) than by direct actions of drugs on sperm function (eg inhibition of glyceraldehyde 3-phosphate dehydrogenase by chloro-compounds). The latter approach holds promise for mankind as human sperm are susceptible to glycolytic inhibition. Future contraceptive developments may arise from production of targeted inhibitors, research on the displacement of sperm proteins in the epididymis and interference with sperm plasma membrane ion channels.
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PMID:Approaches to post-testicular contraception. 1122 1

Harmful micro- and macroscopic effects of the environmental xenoestrogen p-nonylphenol (p-NP) on the male rat reproductive system have been previously reported. In our study, biochemical evidence of epididymal involvement was sought by determining epididymal marker values after exposure at levels below (5, 20 and 50 mg kg-1) and above (100, 250 and 400 mg kg-1) the "no observed adverse effect" level (NOAEL: 50 mg kg-1 day-1). Exposure to p-NL below the NOAEL did not affect biochemical marker values. At levels above the NOAEL, biochemical markers of epididymal function were affected by the exposure of adults, and by maternal exposure (gestational and lactational periods followed by oral exposure until sexual maturity). l-carnitine was unchanged at all levels of exposure. Exposure of adult males to levels above the NOAEL resulted in higher alpha-glucosidase, suggesting increased epididymal secretory activity. This could upset the balance between secretory and reabsorptive function, and could alter the biochemical composition of the epididymal luminal fluid surrounding spermatocytes during the maturation process. Maternal exposure at levels above the NOAEL resulted in higher tartrate-resistant acid phosphatase activity in the caput-corpus epididymidis, which could indicate an oestrogen-mimicking effect.
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PMID:Epididymal markers in rats exposed to the xenoestrogen p-nonylphenol: no biochemical effects at low dosages. 1168 7


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