Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epididymis is the site of posttesticular sperm maturation in the male genital tract. Studies on human epididymides are hampered by the practical inaccessibility of epididymides of healthy men in their reproductive years. The limited use of laboratory animals therefore seems unavoidable. The objective was to establish baseline values of the epididymal markers alpha-glucosidase, glycerophosphocholine (GPC) and carnitine in the lumen of the caput, corpus and cauda epididymidis and in the ejaculate of adult male Chacma baboons and vervet monkeys. In both primates, alpha-glucosidase was found throughout the epididymis and in the ejaculate; values did not vary significantly. In monkeys, the highest concentration of GPC was found in the cauda epididymidis, but smaller amounts were found in the other regions and the ejaculate. In baboons, GPC was absent from the caput, but present in the other regions, including the ejaculate. Carnitine concentrations increased significantly from the caput to the cauda in monkeys and from the caput to the corpus in baboons. With this study, the relative concentration ranges in which these markers are present in the epididymides of these primates have been established. In future studies, changes in concentrations of these substances would probably indicate changes in epididymal function.
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PMID:The presence of alpha-glucosidase, glycerophosphocholine and carnitine in the epididymis and ejaculate of the vervet monkey (Cercopithecus aethiops) and the Chacma baboon (Papio ursinus). 748 36

The present study was performed to determine the usefulness of the alpha-sympathomimetic midodrin for diagnosis and treatment of functional sperm transport disturbances. 140 andrological patients consulting due to severe oligozoospermia, hypospermia or partial/complete retrograde ejaculation were included. Ejaculates were examined 30 min after intravenous injection of 5-15 mg midodrin. Sperm concentration, motility and alpha-glucosidase as a marker of both epididymal function and sufficient passage through the vasa deferentia and the ejaculatory duct were measured and the values compared to those in the ejaculates obtained before therapy. In 23 of 140 patients, sperm concentration or total sperm count was improved by more than 10 million spermatozoa ml-1 or 20 million spermatozoa per ejaculation. Alpha-glucosidase in the seminal plasma increased in two cases. The present study demonstrates that severe oligozoospermia may be caused by functional transport disturbance of semen from the epididymis to the efferent duct system. In these cases, midodrin is of diagnostic and therapeutic value; however, it should be emphasized that its effectiveness cannot be predicted individually.
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PMID:The alpha-sympathomimetic midodrin as a tool for diagnosis and treatment of sperm transport disturbances. 752 69

The way in which the human epididymis modifies spermatozoa during their sojourn in this structure might be clarified by knowledge of the nature of its secretions. We have examined the presence of several lysosomal hydrolases in human epididymal tissue and fluids, and their synthesis and secretion by monolayer cultures. Tissues were obtained from men undergoing orchidectomy for prostatic carcinoma. The enzymes cathepsin D and acid alpha-glucosidase were localised in the lysosomes of epithelial cells from the corpus epididymidis, by an immunocytochemical technique. Cathepsin D was also found in epithelial cells of the efferent ducts within lysosomes, apical vesicles and multivesicular bodies. No immunolocalisation of acid glucosidase in the efferent ducts or on the microvilli of the corpus was demonstrable. Cathepsin D, beta-hexosaminidase (N-acetylglucosaminidase) and alpha-glucosidase were measurable in the luminal fluid from the human corpus epididymidis; beta-hexosaminidase was secreted into the culture medium by confluent monolayers of epididymal and efferent duct cells. Immunoprecipitation of cell extracts and culture medium of these cultures incubated with 35S-methionine revealed that the precursors of cathepsin D and beta-hexosaminidase were synthesized and secreted by such monolayers. Thus, active lytic enzymes are secreted by the human epididymis and could modify sperm membranes.
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PMID:Immunocytochemical localisation of some lysosomal hydrolases, their presence in luminal fluid and their directional secretion by human epididymal cells in culture. 778 Oct 38

The function of accessory sex glands in 29 tobacco smokers, 25 tobacco chewers and 30 non-users of tobacco was investigated by determining the ejaculate contents of various glandular markers: N-acetyl amino sugar and total phosphate (seminal vesicles) zinc and acid phosphatase (prostate gland), and alpha-1,4-glucosidase (epididymis). Both vesicular and prostatic parameters were reduced significantly in smokers compared with non-users of tobacco, whereas these parameters were unchanged in tobacco chewers. This difference may be due either to the difference in constitution of xenobiotics emitted as a result of burning tobacco, or to differences in the pharmacokinetics of the two forms of tobacco consumption. The activity of alpha-1,4-glucosidase was significantly lowered in both types of tobacco users. It is concluded that use of tobacco, especially by smoking, impairs the secretory function of accessory sex glands in man.
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PMID:Effect of tobacco consumption on the function of male accessory sex glands. 856 92

Among azoospermics, the activity of seminal alpha-glucosidase (alpha G) is low in obstruction (OBS) cases, but there is no agreement regarding its value in others. With the hypothesis that a more marked decrease in alpha G activity occurs in OBS than in spermatogenesis arrest (SA), the enzyme was measured in the following groups: (1) vasectomized males (n = 15), (2) azoospermics with OBS (n = 7), (3) azoospermics with SA (n = 11), and (4) fertile males (n = 15). Patients within groups 2 and 3 had a testicular volume > or = 15 mL, no clinical evidence of abnormal epididymis, normal serum gonadotropins, and histological diagnosis. alpha G activities (mU/g protein, means +/- SD) by group were (1) 131 +/- 60, (2) 312 +/- 186, (3) 728 +/- 303, and (4) 1176 +/- 374. All between-group differences were significant (t test, p < .01), except for groups 1 vs. 2 comparison (.05 > p > .01). These results support the notion that SA is associated with a decrease in alpha G that is less marked that seen in OBS. The search for germinal epithelium cells in semen also allows discrimination between these two azoospermic groups.
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PMID:Alpha-1,4-glucosidase activity and the presence of germinal epithelium cells in the semen for differential diagnosis of obstructive and nonobstructive azoospermia. 857 77

The estimation of alpha-glucosidase activity in semen is widely used as a marker of epididymal function. In the present studies, glucosidase activity was evaluated in the different segments of the rat epididymis under various physiological conditions. In addition, the effect of two known male antifertility agents, gossypol and alpha-chlorohydrin, on enzyme activity was evaluated. Enzyme activity was absent from the epididymis of rats aged 10 and 20 days but became detectable at 30 days of age when the adult pattern of distribution (highest activity in the caput epididymis) was established. Enzyme activity was reduced significantly in all segments of the epididymis at 7 days after castration and a significant decrease in activity was also observed following the administration of either gossypol or alpha-chlorohydrin. These findings are consistent with a role for alpha-glucosidase in sperm maturation in the epididymis.
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PMID:alpha-Glucosidase activity in the rat epididymis under different physiological conditions. 929 19

Measurement of alpha-glucosidase (alpha-GLUC) activity by means of a simple colorimetric test using a commercial kit (EpiScreen; FertiPro, Lotenhulle, Belgium) yielded results that were strongly correlated with the values obtained for the neutral iso-enzyme measured by a fluorimetric reference method (r=0.85, P=0.003, n=13). The former method was characterized by a low intra- and inter-coefficient of variation (6.6 and 4.3% respectively). Vasectomized men with azoospermia (n=27) had a significantly lower alpha-GLUC activity in semen than vasectomized men with residual spermatozoa present (n=11, P < 0.01) and men with azoospermia of primary testicular origin (n=33, P < 0.01). Receiver operating curve (ROC) analysis showed alpha-GLUC measurement to be reasonably accurate in differentiation between cases with obstructive versus testicular azoospermia at criterion value 13.5 U/l (sensitivity=82%, specificity= 70%). In cases with spermatozoa present, alpha-GLUC activity and output per ejaculate were positively correlated with sperm concentration (r=0.53 and 0.38, n=472), linear velocity (r=0.35 and 0.30, n=224), curvilinear velocity (r=0.32 and r=0.29, n=224), semen adenosine triphosphate (r=0.35 and 0.26, n=64), the concentration of 5alpha-dihydrotestosterone (r=0.31 and 0.29, n=74), and gamma-glutamyltransferase activity (r=0.62 and 0.32, n=275) in seminal plasma. The activity of alpha-GLUC was inversely correlated with ROS generation after 12-myristate, 13-acetate phorbol ester stimulation (r=-0.27, n=104), and both alpha-GLUC activity and total output were inversely correlated with the concentration of peroxidase-positive white blood cells among samples with > or =1x10(6)/ml of these cells (r=-0.30 and -0.19, n=165). It is concluded that simple photometric measurement of alpha-GLUC activity in seminal plasma reflects the functional state of the epididymis and may be helpful for the differential diagnosis of certain cases with azoospermia.
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PMID:Seminal plasma alpha-glucosidase activity and male infertility. 957 18

Low alpha-glucosidase activity in seminal plasma is a marker of epididymal obstruction. The criterion standard for determining activity is the epididymal specific method, whereby the neutral iso-enzyme, specifically produced by the epididymis, is measured. A kit that determines total alpha-glucosidase activity (neutral iso-enzyme and the acid iso-enzyme originating from the prostate) has become available. The objective of the laboratory-based study was to compare alpha-glucosidase activity values measured by both the EpiScreen and the epididymal specific method, to determine if the kit may provide reliable results to substitute the neutral iso-enzyme specific method in the routine clinical setting. The neutral iso-enzyme activity according to both methods was measured in seminal plasma of 23 post-vasectomy and 24 normozoospermic patients. Significant differences (P < 0.05) were found between the activities measured according to both methods, but these differences pertained mostly to high values (> 40 mU ejaculate-1), which was not clinically significant. In conclusion, the epididymal specific method is best suited for research purposes, but the EpiScreen kit is convenient for routine use in infertility clinics.
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PMID:A comparative study of the EpiScreen kit and a conventional method for the determination of seminal alpha-glucosidase activity. 963 92

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


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