Origin of maltase and variations in infertile men

Alpha-1,4-glucosidase activity and the presence of germinal epithelium cells in the semen for differential diagnosis of obstructive and nonobstructive azoospermia

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.

Improvement in the assessment of human epididymal function by the use of inhibitors in the assay of alpha-glucosidase in seminal plasma

Seminal alpha-glucosidase has been used clinically as a marker of epididymal function. In this study enzyme inhibitors were used to increase the specificity of the human seminal alpha-glucosidase assay and improve its diagnostic value as an indicator of distal epididymal occlusion in cases of azoospermia. Sodium dodecylsulphate was added to the sample to eliminate the interfering acid isoenzyme secreted by the prostate gland, and castanospermine was used with semen pools to provide a semen blank for the assay by eliminating non-glucosidase-regulated degradation of the substrate. With both inhibitors included in the assay, glucosidase activity in semen samples from 17 fathers was measured to provide reference values for the clinic (lower threshold 18 mU per ejaculate). With the improved assay glucosidase was non-detectable in 8 out of 11 cases of proven and 5 out of 8 cases of suspected ductal obstruction; other azoospermic patients with distal occlusion had values below 11 mU per ejaculate.

Alpha-glucosidase activity and sperm motility

We correlated the activity of alpha-glucosidase in seminal plasma with the motility and differential motility of sperm. Significant positive correlations were found between the alpha-glucosidase activity and both motility and the percentage sperm with good forward progression. This supports the use of alpha-glucosidase in semen as a marker of epididymal function and specifically of the development of motility.

Alpha-glucosidase as a specific epididymal enzyme marker. Its validity for the etiologic diagnosis of azoospermia

Azoospermic semen was obtained from 39 vasectomized men and 93 patients consulting for infertility. The latter underwent bioclinical investigations including measurement of plasma FSH and testicular biopsies. Carnitine content and alpha-glucosidase activity in semen samples were measured. The activity of alpha-glucosidase was determined systematically by a semiquantitative microtechnique and was verified by a spectrophotometric assay. A positive correlation was observed between carnitine and alpha-glucosidase activity. Both parameters were severely diminished in semen from the vasectomized men and the patients suffering from a complete obstruction of the genital tract. Enzyme activity was the most discriminant parameter in terms of sensitivity and specificity. The measurement of alpha-glucosidase in semen is a simple and sensitive method for determining the origin of azoospermia when used in conjunction with assays for plasma FSH.

Similar biochemical properties of human seminal plasma and epididymal alpha-1,4-glucosidase

We have studied some characteristics of alpha-1,4-glucosidases in human male reproductive organs in order to obtain information on the origin of the enzyme in seminal plasma. Acid and neutral enzymes could be distinguished on the basis of their selective inhibition either by SDS (acid enzyme) or MTT (neutral enzyme). Only the epididymis contained a significant amount of SDS resistant neutral alpha-1,4-glucosidase which was comparable to what has been isolated in seminal plasma. The similarity of epididymal and seminal plasma neutral enzymes was further confirmed by ultracentrifugation on sucrose density gradients, which permitted a complete separation of neutral (11S) and acid (4S) iso-enzymes. The 11S form was present in epididymis and in seminal plasma, but was totally absent in seminal vesicles, prostates and testis. The epididymal enzyme also had some of the unique characteristics found in the seminal plasma enzyme: it precipitated upon dialysis against distilled water, and its mobility on SDS polyacrylamide gel electrophoresis was identical to that of form 1 in seminal plasma. These results, although they do not constitute absolute proof of the identity of epididymal and seminal plasma alpha-glucosidase, certainly provide strong support for this hypothesis.

Biochemistry of the nonhuman primate prostate and seminal vesicles. I. Some chemical parameters

Normative biochemical values for cranial prostate, caudal prostate, and seminal vesicles were obtained in four macaque species and in baboons, with a view to chemical comparison of the cranial lobe with the other two tissues. The cranial prostatic lobe and the seminal vesicles were both significantly different from the caudal prostate in prostatic acid phosphatase activity. However, citric acid and lactate dehydrogenase in the cranial lobe were comparable to concentrations in the caudal lobe and significantly different from the seminal vesicles. Dihydrotestosterone was higher in content than testosterone in all tissues of each species examined. The nonhuman primate cranial lobe seems to be a link between the seminal vesicles and the caudal prostate.

Comparative study of alpha-glucosidase activities in blood and seminal plasma of rams

1. This study was undertaken to characterize the alpha-glucosidase present in blood and seminal plasma of two strains of pure-bred rams which are known as seasonal breeders. 2. pH profiles and activity levels were investigated in blood and seminal plasma using a sensitive spectrophotometric assay with para-nitrophenyl-alpha-D-glucoside as substrate. 3. According to their pH optimum, blood plasma and seminal plasma alpha-glucosidases were typically neutral and acid enzymes and significant differences were recorded in their physico-chemical properties, establishing the tissue specificity of the enzyme. 4. Notwithstanding the tissue under study, the nature of the alpha-glucosidase activity was similar in both strains of pure-bred rams.

Neutral alpha-1,4-glucosidase in human seminal plasma: molecular forms in varicocele and after vasectomy

Neutral alpha-1,4-glucosidase catalyzes the breakdown of oligosaccharides in several tissues including the reproductive organs, and we have demonstrated the presence of two molecular forms (F1 and F2) of the enzyme in human seminal plasma. The identification of these forms can be achieved by sucrose density gradient analysis and/or electrophoresis in the presence of detergents. Individuals with normal sperm analyses or affected by a varicocele, thus showing normo- or oligoasthenozoospermia, show a similar prevalence of F1 only and F1 + F2 forms, while the presence of F2 alone becomes obvious following vasectomy. In conclusion, molecular forms of the enzyme do not appear to be indicative of the presence of a varicocele, but they may reflect modifications in the secretory function of specific reproductive organs (prostate) or glands (seminal vesicles), as observed in the course of an obstructive abnormality at the epididymal or vas deferens level.

Enzymes in the seminal plasma from azoospermic men: correlation with the origin of their azoospermia

Semi-quantitative estimations of the activities of 65 enzymes were studied for cases of azoospermia in an attempt to correlate the seminal enzyme profile with the origin of the azoospermia. One single enzyme--alpha-glucosidase--showed variation. All other specificities tested gave identical results for all the azoospermic samples and for normal controls. The alpha-glucosidase activity that is present in normal semen was absent from samples from patients with azoospermia associated with a complete obstruction of the genital tract, and also from all semen samples from vasectomized subjects. This enzyme appears to be secreted by the epididymis, and the activity present in azoospermic semen can provide information concerning the origin of the azoospermia and the functional state of the epididymis. Positive but reduced alpha-glucosidase activity appears to be frequently associated with inflammatory disease. The consequences of these findings are discussed.

Enzyme comparative study of spermatozoa and seminal plasma in normal and subfertile man

A semiquantitative colorimetric micromethod (APIZYM) was used to study the enzyme profiles of seminal plasma and of spermatozoa. Reactions with 65 different substrates are simultaneously tested in a single specimen. These substrates (principally naphtolic) allow the detection of hydrolytic enzymes (esterases, phosphatases, and peptidases) and of dehydrogenases potentially involved in sperm metabolism and in the process of fertilization. The usual sperm enzymes were regularly observed: C3-C4 esterases, amino acid arylamidases, acrosine, phosphatases, glutamyl transpeptidase, and various osidases. Among the dehydrogenases we observed a striking predominance of the enzymes of the hexose monophosphate shunt and of LDH. Seminal plasma has an enzyme pattern very similar to that of spermatozoa except for the absence of acrosine and of some dehydrogenases. This unexpected similarity is discussed. The gametes from subfertile donors do not at first sight differ in their enzyme pattern from those from fertile donors. Moreover, we found no marked differences between zymograms of seminal plasma from normal, subfertile, or even azoospermic patients. Deep freezing does not modify the hydrolytic enzymes of human sperm either quantitatively of qualitatively, but the dehydrogenases of the hexose monophosphate shunt are adversely affected (60% loss of activity for G 6 PDH, and 30% for 6 PGDH); LDH is not affected. The consequences on fertilizing capacity of frozen semen are discussed.

Androgen binding in the baboon prostate

Androgen receptors were identified and partly characterized in cytosols of the caudal and cranial prostatic lobes of a 24-hr castrate baboon. Binding of cyproterone acetate (CA) to testosterone-binding globulin (TeBG) in baboon serum was negligible and therefore was an appropriate unlabeled competitor for distinguishing high-affinity binding of tritiated dihydrotestosterone (3H-DHT) to serum contaminants and receptors in cytosol preparations when multiple-point saturation analyses and removal of free steroid by charcoal adsorption were used. Specificity of androgen binding was demonstrated by the inability of diethylstilbestrol, a synthetic estrogen known to have low binding affinity for TeBG, to displace 3H-DHT from the receptor protein. The number of high-affinity binding sites and the dissociation constant of the androgen receptor calculated for the caudal lobe were 102 fmoles/mg cytosol protein and 4.0 X 10(-9) M, respectively; corresponding values for the cranial lobe were 49 fmoles and 1.3 X 10(-9) M.

Purification and properties of neutral alpha-1,4 glucosidase from human seminal plasma

Following a preliminary fractionation of neutral alpha-glucosidase (E.C. 3.2.1.20) from human seminal plasma, we have shown by ion exchange chromatography, Sephadex G-200 filtration, and adsorption chromatography that this alpha-glucosidase activity corresponded to two isoenzymes having the same ability to hydrolyse p-nitrophenyl-alpha-D-glucopyranoside. Both isoenzymes present a heat-stable fraction at 60 degrees C, require the presence of divalent cations in the incubation medium to demonstrate their glycolytic activity, and are inhibited by maltotriose and maltose. They have a molecular weight of approximately 200,000 daltons and different sedimentation profiles on sucrose density gradient. This basic knowledge appears to be the prerequisite for further studies dealing with the importance of such isoenzymes as markers of epididymal function in male fertility.