Coagulation, liquefaction and viscosity of human semen

Deletion of a Seminal Gene Cluster Reinforces a Crucial Role of SVS2 in Male Fertility

Multiple genes, whose functions or expression are overlapping, compensate for the loss of one gene. A gene cluster in the mouse genome encodes five seminal vesicle proteins (SVS2, SVS3, SVS4, SVS5, and SVS6). These proteins are produced by male rodents and function in formation of the copulatory plug following mating. SVS2 plays an essential role in the successful internal fertilization by protecting the sperm membrane against a uterine immune attack. We hypothesized that the four remaining seminal vesicle proteins (SVPs) of this gene cluster may partially/completely compensate for the deficiency of SVS2. For confirming our hypothesis, we generated mice lacking the entire SVP-encoding gene cluster and compared their fecundity with Svs2-deficient (Svs2^−/−) mice; that is, mice deficient in Svs2 alone. A single loxP site remained after the deletion of the Svs2 gene. Therefore, we inserted another loxP site by combining the CRISPR/Cas9 system with single-stranded oligodeoxynucleotides (ssODN). Male mice lacking the entire SVP-encoding gene cluster (Svs2–6^−/− mice) and thereby all five SVP proteins, generated by the deletion of 100kbp genomic DNA, showed low fecundity. However, the fecundity level was comparable with that from Svs2^−/− male mice. Our results demonstrate that SVS3, SVS4, SVS5, and SVS6 do not function in the protection of sperm against a uterine immune attack in the absence of SVS2. Thus, Svs2 is the critical gene in the SVP gene cluster.

Evaluation of Seminal Fructose and Citric Acid Levels in Men with Fertility Problem

CONTEXT

Male infertility is a medical problem, attributed to 50% of infertility. Seminal plasma can be an anticipating factor as it comprises secretions of accessory sex gland, thus offering novel and precise ways to understand potential roles of these biochemical markers in male infertility.

AIM

The objective of this study was to assess the correlation between biochemical markers and sperm parameters in envisaging male infertility.

SUBJECTS AND DESIGN

We enlisted 105 men with fertility issue as patients and 25 fertile men as controls to evaluate the sperm parameters and biochemical markers, namely fructose and citric acid in ascertaining male infertility.

MATERIALS AND METHODS

The semen samples from patients were collected properly and analyzed according to the World Health Organization-2010 manual. Later samples were centrifuged, seminal plasma was collected, and biochemical markers assessment was carried out by standard protocols.

STATISTICS

Descriptive statistics, independent t-test, one-way ANOVA, and Pearson correlation were used for statistical analysis of different variables using SPSS 20.0. The mean sperm count and motility by all infertile conditions displayed a significant difference when compared with the controls (P < 0.05).

RESULTS

The mean fructose levels of oligozoospermia showed a nonsignificance difference when compared with controls (P < 0.05). Asthenozoospermia, asthenoteratozoospermia, and azoospermia had a significance difference (P < 0.05) for citric acid levels. Pearson correlation coefficient showed significant negative correlation of sperm count (r = -0.564) and sperm motility (r = -0.574) with fructose levels. Whereas seminal citric acid concentration had a positive correlation with sperm count (r = 0.458) and sperm motility (r = 0.446).

CONCLUSION

Therefore, evaluation of certain biochemical markers of seminal fluid may benefit in understanding the functionality of accessory glands which subsidizes significantly to the seminal volume.

Mechanical processing of hyperviscous semen specimens can negatively affect sperm DNA fragmentation

INTRODUCTION

The present study compared the DNA fragmentation in human sperm samples with reduced, physiological, and increased viscosity in order to evaluate whether the process used to reduce viscosity (expulsion of semen through a needle and syringe) alters significantly sperm DNA fragmentation.

METHODS

The seminal parameters of semen samples from 123 patients were evaluated and classified according to their viscosity. Samples with increased viscosity were submitted to a process of expulsion of semen through a 10-mL syringe and an 18-gauge (18G) needle to reduce the seminal viscosity. The DNA fragmentation of all samples was analysed using TUNEL assay (Terminal deoxynucleotidyl transferase mediated dUTP Nick-end labelling assay); in samples with increased viscosity, the fragmentation was assessed before and after the process of expulsion with syringe and needle.

RESULTS

There was no difference in DNA fragmentation between groups with different viscosity (P = 0.857). A significantly increase in sperm DNA fragmentation after expulsion of hyperviscous semen through the syringe was observed (P = 0.035).

CONCLUSION

There was no difference in DNA fragmentation rate between samples with reduced, increased and physiological viscosities; however, the physical process of expulsion of semen through a syringe and needle increased sperm DNA fragmentation.

Semen analysis and sperm function tests: How much to test?

Semen analysis as an integral part of infertility investigations is taken as a surrogate measure for male fecundity in clinical andrology, male fertility, and pregnancy risk assessments. Clearly, laboratory seminology is still very much in its infancy. In as much as the creation of a conventional semen profile will always represent the foundations of male fertility evaluation, the 5th edition of the World Health Organization (WHO) manual is a definitive statement on how such assessments should be carried out and how the quality should be controlled. A major advance in this new edition of the WHO manual, resolving the most salient critique of previous editions, is the development of the first well-defined reference ranges for semen analysis based on the analysis of over 1900 recent fathers. The methodology used in the assessment of the usual variables in semen analysis is described, as are many of the less common, but very valuable, sperm function tests. Sperm function testing is used to determine if the sperm have the biologic capacity to perform the tasks necessary to reach and fertilize ova and ultimately result in live births. A variety of tests are available to evaluate different aspects of these functions. To accurately use these functional assays, the clinician must understand what the tests measure, what the indications are for the assays, and how to interpret the results to direct further testing or patient management.

Association between kallikrein-related peptidases (KLKs) and macroscopic indicators of semen analysis: their relation to sperm motility

Human kallikrein-related peptidases (KLKs) are a family of proteases, the majority of which are found in seminal plasma and have been implicated in semen liquefaction. Here, we examined the clinical value of seminal KLKs in the evaluation of semen quality and differential diagnosis and etiology of abnormal liquefaction and/or viscosity. KLK1–3, 5–8, 10, 11, 13, and 14 were analyzed, using highly specific ELISA assays. Samples were categorized into four clinical groups, according to their state of liquefaction and viscosity. Data were compared between the clinical groups and in association with other parameters of sperm quality, including number of motile sperms, straight line speed, sperm concentration, volume, pH, and patient age. Seminal KLKs were found to be differentially expressed in the four clinical groups. Combination of KLK2, 3, 13, and 14 and KLK1, 2, 5, 6, 7, 8, 10, 13, and 14 showed very strong discriminatory potential for semen liquefaction and viscosity, respectively. Liquefaction state was associated with several parameters of sperm motility. Finally, KLK14 was differentially expressed in asthenospermic cases. In conclusion, the expression level of several seminal plasma KLKs correlates with liquefaction and viscosity indicators of semen quality and may aid in their differential diagnosis and etiology.

Secretory proteins of human seminal vesicles and their relationship to lipids and sugars

Proteins secreted by human seminal vesicles are strongly positively charged. Cellulose acetate electrophoresis show how the presence of two protein bands of vesicular origin (N3 and N4). When studied on SDS-PAGE there are three main bands of molecular weight 67, 45 and 40 kDa, respectively. These proteins may be separated by a chromatographic process using gel filtration on Sephadex G 25 M and ion exchange chromatography on CM and SP Sephadex C 50. Fructose, secreted by seminal vesicles, is excreted with specific proteins and these complexes take part to coagulum formation. During liquefaction glucose appears progressively and fructose is released from complexes with proteins. Interconversion processes that transform fructose into glucose, originate from prostatic secretion. In man, the liquefaction process seems to be not due to proteolysis, but by the way of other mechanisms that transform vesicular proteins of very high molecular weight into sub-units with lower molecular weights in the first minutes after ejaculation. In species other than man, i.e. lemurian, fructose takes part in the coagulation process with other components (albumin, ions, -SH groups). Cholesterol appears to be in relation with proteins which have high molecular weights. Half of phospholipid content of seminal plasma is probably free. Incubation of seminal plasma with spermatozoa show that these cells use triglycerides for their metabolism. The ratio between cholesterol and phospholipids is an important marker for the capacitation-decapacitation process.

Seminal hyperviscosity is associated with poor outcome of in vitro fertilization and embryo transfer: a prospective study

OBJECTIVE

To investigate the effect of increased seminal viscosity on fertilization, implantation, and pregnancy outcome in patients undergoing in vitro fertilization/ intracytoplasmic sperm injection (ICSI).

DESIGN

Prospective study.

SETTING

University-affiliated infertility center.

PATIENT(S)

One hundred fifty-eight infertile couples (168 cycles) with increased seminal viscosity and 129 infertile couples (138 cycles) with normal seminal viscosity as controls.

INTERVENTION(S)

In vitro fertilization using conventional insemination or ICSI.

MAIN OUTCOME MEASURE(S)

Fertilization, embryo quality, implantation, and pregnancy rates (PR) were evaluated.

RESULT(S)

Patient age and the cause of infertility were similar between the two groups. Sperm count (36.9 +/- 34.0 vs. 28.1 +/- 25.6) and motility (41.5 +/- 19.2 vs. 37.0 +/- 20.5) was higher in the control group compared to the study group. Fertilization rate after IVF (50.4% vs. 64.6%), clinical PR (28% vs. 39.9%), and the implantation rates (10.5% vs. 16.5%) were significantly lower in patients with hyperviscosity compared to the control group.

CONCLUSION(S)

The lower implantation rate and clinical PR in couples with seminal hyperviscosity may be attributed to biophysical alterations or chemical changes of the ejaculate that could impact sperm DNA despite the presence of apparently normal motile sperm for the IVF/ICSI procedure.

Semen-coagulating protein, SVS2, in mouse seminal plasma controls sperm fertility

Mammalian seminal plasma is known to contain a decapacitation factor(s) that prevents capacitation and thus, the fertility of sperm. This phenomenon has been observed in experiments conducted in vitro that assessed the inhibition of epididymal sperm fertility by seminal plasma or by the purified decapacitation factor. However, the phenomenon of decapacitation has not yet been characterized in vivo. In the present study, we demonstrate that seminal vesicle protein secretion 2 (SVS2), which is a 40-kDa basic protein and a major component of the copulatory plug, enters the uterus and interacts with ejaculated sperm heads after copulation. The SVS2-binding region of sperm changed from the postacrosomal region to the equatorial segment, while the sperm migrated through the uterus and finally disappeared in the oviduct. Furthermore, SVS2 reduced the fertility of epididymal sperm. The sperm treated with SVS2 decreased the percentage of fertilized oocytes from 60% to 10%. The capacitation state was assessed by protein tyrosine phosphorylation and the comprehensiveness of the acrosome reaction. SVS2 functioned to maintain sperm in the uncapacitated state and to reverse capacitated sperm to the uncapacitated state. We found that the fertility of ejaculated sperm is associated with SVS2 distribution in the female reproductive tract. These results indicate that SVS2 functions as a decapacitation factor for mouse sperm.

Seminal Factor VIII and von Willebrand Factor: a possible role of the conventional clotting system in human semen?

Factor (F) VIII circulates in blood complexed with von Willebrand Factor (vWF). Deficiency or defect accounts for haemophilia A and vWF disease. In blood, FVIII functions as a co-factor for FIXa in the activation of FX. Human semen coagulates and liquefies in a process that resembles and has some links with the conventional haemostatic process. A study elsewhere has detected traces, but not measurable levels, of FVIII coagulant activity (FVIII:C). In the present study we have assessed FVIII antigen (FVIII:Ag), FVIII:C and vWF antigen (vWF:Ag) levels in 159 semen specimens obtained from sub-fertile (n = 21), normally fertile (n = 38), fertile donors (n = 32), and vasectomized men (n = 57). Seminal FVIII:Ag levels were also measured in a group defined by several parameters derived from the World Health Organization (WHO) fertility criteria, termed "pooled normal semen parameters" (PNSP). Factor VIII:Ag levels were compared with conventional fertility parameters. In addition, both FVIII:C and vWF:Ag were assessed in a separate group of normal individuals (n = 11). Factor VIII:Ag, FVIII:C and vWF were present and quantifiable in human semen. Factor VIII:Ag levels were significantly lower in vasectomy subjects compared with donors (p = 0.01) or PNSP group (p = 0.01). Several trends taken together suggest an associations between FVIII:Ag and semen quality. Parallel investigations demonstrate FV, FVII, FVIIa, FIX, FIXa, FXa, FXI, FXII, tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in semen. The present report therefore provides further evidence for the presence of a functioning clotting system in human semen.

Association of eppin with semenogelin on human spermatozoa

Eppin (SPINLW1; GeneID, 57119) is a single-copy gene encoding a cysteine-rich protein found only in the testis and epididymis, which contains both Kunitz-type and WAP-type four disulfide core protease inhibitor consensus sequences. This study demonstrates that, in seminal plasma and on human spermatozoa following ejaculation, Eppin is bound to semenogelin I (Sg). Six different experimental approaches: 1) immunoprecipitation from spermatozoa and seminal plasma with anti-Eppin, 2) colocalization in semen and spermatozoa, 3) incubation of recombinant Eppin (rEppin) and rSg and immunoprecipitation with either anti-Eppin or anti-Sg, 4) far-Western blotting of Eppin and Sg, 5) Saturation binding of 125I-Sg to Eppin, which is competed by unlabeled Sg, and 6) direct binding of 125I-Sg to Eppin on a blot, all demonstrate that Eppin and Sg bind to each other. To study the specificity of binding, recombinant fragments of Eppin and Sg were made and demonstrate that the Eppin(75-133) C-terminal fragment binds the Sg(164-283) fragment containing the only cysteine in human Sg I (Cys-239). Reduction and carboxymethylation of Cys239 blocks binding of 125I-rEppin, indicating that a disulfide bond may be necessary for Eppin binding. The physiological significance of the Eppin-semenogelin complex bound on the surface of ejaculate spermatozoa lies in its ability to provide antimicrobial activity for spermatozoa, which has been reported for both Eppin and semenogelin-derived peptides, and in its ability to provide for the survival and preparation of spermatozoa for fertility in the female reproductive tract.

Viscosity of human seminal fluid: role of lysozyme

The aim of this research was to evaluate the role of lysozyme in the phenomenon of seminal hyper-viscosity. The enzyme was determined in 142 samples of seminal plasma either leucospermic or not, with or without active macrophages classified according to their consistency (normal or high). The kinetic method with Micrococcus lysodeikticus as substrate was employed. No difference was found in enzymatic concentration expressed in nmol/L of enzymatic protein (mean +/- 2 SEM) on comparing normal and high seminal consistency groups, while differences proved highly significant in batches either leucospermic or not (n = 44, 197.2 +/- 51.3 vs. n = 98, 108.3 +/- 12.8; p < .0005). On subdividing the normal and high-consistency groups according to the count of polymorphonuclear leucocytes and the macrophagic responses, differences were also significant (p < .005 in both cases). Lysozyme concentration increases in presence of leucospermic reaction. In vitro lysozyme addition showed no significant effect on samples with high consistency. The results indicate that lysozyme plays no direct role in the phenomenon of seminal hyperviscosity, although its deficiency in cases of chronic infections may prove a factor aggravating the clinical picture.

Dithiothreitol effects on human sperm quality

Human semen normally coagulates immediately after ejaculation and then undergoes liquefaction during the next 15 to 60 minutes. Incomplete seminal liquefaction can result in impaired sperm motility and make clinical evaluation and manipulation difficult. Dithiothreitol, a mucolytic agent that reduces the mucoprotein disulfide bonds in sputum, has been found to induce liquefaction of incompletely liquefied semen in vitro. We studied the effects of dithiothreitol on sperm motility, viability, acrosomal integrity and morphology. A semen sample was provided by 45 healthy, young men at the University of Arizona. Of the specimens 10 (22%) demonstrated incomplete liquefaction. Sperm motility and motion characteristics of untreated (control) semen and semen treated with dithiothreitol were objectively evaluated using computer assisted semen analysis. Sperm cell membrane integrity and mitochondrial integrity were measured by fluorescence microscopy using the deoxyribonucleic acid specific fluorochrome propidium iodide and the mitochondria specific fluorochrome rhodamine-123, respectively. Acrosomal integrity was determined using the fluorescent stain chlortetracycline. Sperm morphology was evaluated using bright field microscopy. For completely liquefied semen (35 cases) dithiothreitol reduced sperm motility (59.1 +/- 1.2% untreated versus 53.2 +/- 1.2% treated, p < 0.01) and motion characteristics. However, dithiothreitol had no statistically significant effect on motility on sperm in the group with incompletely liquefied semen (10 cases). Sperm cell membrane, mitochondrial and acrosomal integrity was unaffected by dithiothreitol regardless of liquefaction status. Dithiothreitol caused a significant increase in abnormally large sperm head morphology in the group with completely liquefied semen. The minimal effects of dithiothreitol on sperm motility traits and viability support its use as a possible aid in the evaluation and manipulation of incompletely liquefied semen.

Deficiency in major high molecular-weight seminal proteins in men producing poorly coagulating and alkaline liquid ejaculates

Using SDS-PAGE three major high molecular-weight coagulum proteins (57, 75 and 79 kD) were identified in unliquefied human ejaculates. Washed coagulum was prepared at pH 4.5 and demonstrated negligible proteolysis as determined by a highly sensitive fluorescamine-based method. Laser densitometric scanning of these high molecular-weight proteins in unliquefied ejaculates in relation to their coagulational failure revealed that the total content of 57, 75 and 79 kD proteins in whole semen represented approximately 44% of levels in the normally coagulated, approximately 24% in poorly coagulated (P less than 0.005) and approximately 3% in the non-coagulated (alkaline liquid, P less than 0.001) samples. The findings imply that these predominant high molecular-weight proteins play a major role in human seminal coagulum formation.

Seminal plasma biochemistry. III: Characterization of coagulum components

Human seminal plasma components involved in coagulum formation have been isolated by liquefaction and reformation of the coagulum in acidic and neutral buffers, respectively. The SDS-PAGE profile of the isolated coagulum (recoagulum) is similar to that reported for the native coagulum immediately following liquefaction. Thus the recoagulum may be considered to represent the native coagulum. Electrophoresis of the recoagulum under non-denaturing conditions reveals the presence of both positively and negatively charged components. These components are sialoglycoproteins that bind copper. Based on these results, a possible mechanism for coagulum formation and liquefaction is discussed.

Demonstration of the role of prostate-specific antigen in semen liquefaction by two-dimensional electrophoresis

Two-dimensional protein profiles of human semen, prostatic fluid, and seminal vesicle fluid were compared to demonstrate changes in the protein composition of human semen before and after liquefaction. Semen specimens were obtained from a volunteer. Prostatic fluid specimens were collected by rectal massage from patients visiting a urology clinic. Samples of seminal vesicle fluid were collected by needle aspiration from isolated seminal vesicles, which were removed at surgery. All specimens were prepared and processed according to the ISO-DALT system for separation of proteins in two-dimensional gels. Following electrophoresis, protein spots in the gels were visualized by silver staining. Prostatic fluid and seminal vesicle fluid showed their characteristic protein profiles. The protein profile of human semen contained specific proteins of both prostatic fluid and seminal vesicle fluid. One major group of proteins in seminal vesicle fluid (Mw 28,000-68,000 daltons), designated as seminal vesicle-specific antigen, was observed in freshly ejaculated human semen, but disappeared from the two-dimensional profile when the ejaculate was allowed to stand at room temperature for 30 min. When prostatic fluid or prostate-specific antigen was mixed with seminal vesicle fluid and incubated at 37C for 30 min, the seminal vesicle-specific antigen also disappeared from the two-dimensional profiles. The findings indicate that seminal vesicle-specific antigen, a group of predominant proteins in seminal vesicle fluid, is the structural component of seminal coagulum, and that prostate-specific antigen is the enzyme which digests seminal vesicle-specific antigen and liquifies semen coagulum.

Seminal plasma biochemistry. IV: Enzymes involved in the liquefaction of human seminal plasma

A significant positive correlation was found between the liquefaction time of human seminal coagula and bound sialic acid. There was also a similar relationship between bound sialic acid and the enzyme sialyl-transferase. This suggests that the degree of sialylation of the components of seminal coagulum are important in determining the liquefaction time of the coagulum. These results support previous findings. The coagulum is considered to be composed of glycoprotein-metal ion complexes, and the initial stage of liquefaction results from the reduction of these metal ions by L-ascorbic acid. The removal of hydrogen peroxide, generated by the oxidation of L-ascorbic acid, requires the presence of glutathione peroxidase and glutathione reductase. These enzymes have been identified in human seminal plasma and their possible physiological importance is discussed.

Biochemical parameters of slowly liquefying human ejaculates

Abnormality in liquefaction of human semen is associated with poor scoring in postcoital tests and may lead to subfertility. A relative study on the seminal plasma characteristics of slowly and normally liquefying human ejaculates has been made. A multitude of seminal vesicular and prostatic components in the seminal plasma of eight slow-liquefying ejaculates from 4 men were compared with ten normally liquefying ejaculates from different healthy volunteers. For 60% liquefaction, the time taken by these two types of ejaculates was 46 and 7 min, respectively. The levels of the components that are mainly secreted by the seminal vesicles were similar in both the groups. But all the prostatic components demonstrated significantly (p less than 0.001) decreased levels in the slow-liquefying group from those in the group being compared. It was concluded that relative decrease in the prostatic activity with respect to that of the seminal vesicles appears to be the cause of slow-liquefaction.

Seminal vesicle-secreted proteins and their reactions during gelation and liquefaction of human semen

The comparison of measurements of fibronectin and lactoferrin in ejaculates from vasectomized men, subjects with functional deficiency or aplasia of the seminal vesicles, and reference subjects provided evidence that both the fibronectin and the lactoferrin in human seminal fluid originate from the seminal vesicles and the ampullae. The fibronectin is incorporated in the framework of the seminal gel formed during the immediate postejaculatory phase, whereas the lactoferrin remains in solution. In the seminal gel fibronectin is linked to its predominant structural protein, a high molecular weight seminal vesicle protein (semenogelin). Both the gel-bound fibronectin and semenogelin are progressively fragmented and solubilized by the abundant prostatic kallikrein-like protease (prostate-specific antigen) during and after seminal gel liquefaction. Lactoferrin remains essentially unaffected by the seminal proteases.

Amino acid content of human semen in normal and infertility cases

Reports concerning the content of alpha-amino-nitrogen and amino-acids in human semen are few and results are different with authors. These variations could be explained by the no considerations of the changes due to liquefaction. In order to test this possible effect, measures were performed 30 mm, 1 h 30, 3 h and 5 h after seminal collection. Deproteinization was obtained with mixture of barium hydroxide and zinc sulfate. The data were compared to results of spermiogram. According to seminal parameters, 6 categories were distinguished. Measures showed a significant increase of the alpha-amino-nitrogen with time. The chromatography separation showed 19 different free amino-acids. The content of the most amino-acids increased with time except phosphoserine, taurine and ornithine; several amino-acids appear. In cases of azoospermia, levels of alpha-amino-nitrogen and amino-acids were lower. The content of amino-acids is not influenced by the spermatozoa count that seems to indicate their glandular origins. The free amino-acids content had to be considered in regard to cases with low liquefaction. But, in all cases it appears necessary to use a strictly standardized method since results are influenced with time.

Investigation of flow behaviour (viscosity) from human seminal fluid with a rotational viscosimeter

Flow behaviour of human seminal fluid was studied with a rotational viscometer (Rotoviso RV 100 with low shear sensor CV 100 made by Haake Karlsruhe) regarding normozoospermia, oligozoospermia, azoospermia and initially prolongated liquefaction time. Measurement is done according to DIN 53018 (procedure) and DIN 53019 (evaluation) and viscosity is given in millipascal seconds (mPas). At a shear rate of 90 s-1 the absolute viscosity n is 7.86 +/- 5.51 mPas (n = 104); without the initial viscous ejaculate (n = 23) viscosity n at 90 s-1 was 5.55 +/- 1.71 mPas (n = 81). Within the group of viscous ejaculates the average viscosity is distinctly higher than the one in the group of normal ejaculates. In both groups there is no correlation between number of spermatozoa and viscosity and motility and viscosity. A reason for the different flow behaviour is not yet found.

The predominant protein in human seminal coagulate

The predominant protein in human seminal vesicle secretion constitutes the structural protein of coagulated semen. This high molecular weight protein (HMW-SV-protein) is stable in seminal vesicle secretion during in vitro storage at 37 degrees C for at least 20 h, but is rapidly cleaved on mixing with prostatic proteases. Seminal coagulate, washed free of soluble components, is dissoluble by 2 to 3 mol/l of guanidine-HCl. Although dithiothreitol added to seminal coagulate does not liquefy the clot, complexes between HMW-SV-proteins are broken up by reduction under denaturing conditions, which suggests that the non-covalent linkages of HMW-SV-proteins are essential in the clot. Prostatic proteases cleave the HMW-SV-protein during liquefaction of ejaculated semen to a series of labile proteins. These proteins are further cleaved to peptides of successively decreasing size after completed liquefaction. The cleavage of the HMW-SV-protein is the major cause of the fast shift of the electrophoretic pattern of seminal proteins if semen is stored without protease inhibitors.

Physical properties and non-enzymic components of human ejaculates. Relationship to spontaneous liquefaction

The relationship between spontaneous liquefaction and the characteristics of ejaculated human semen has been investigated. The liquefaction time of ejaculates was found to be significantly correlated with their extent of coagulation and some non-enzymic components of seminal plasma. Human ejaculates were classified into 3 distinct groups depending on their liquefaction time, and the groups were characterized physico-chemically. The liquefaction time also revealed a low but significant negative correlation with semen volume. It is concluded that an individual's ejaculatory characteristics can be evaluated simply by determining its liquefaction time.

Liquefaction of coagulated human semen

Liquefaction of coagulated human semen was inhibited by o-phenanthroline; subsequent addition of Zn2+ reversed this inhibition, but not if the coagulum was repeatedly washed before Zn2+ was added. No liquefaction of the coagulum occurred when Fe2+ was added (in a 1:3 molar ratio to o-phenanthroline), and the gel repeatedly washed. This o-phenanthroline-depleted coagulum was liquefied by resuspended pellet from ultracentrifuged pooled seminal plasma. In denatured and reduced semen coagulate, we identified the 52 kDa, 71 kDa, and 76 kDa protein bands of the predominant seminal vesicle protein. The protein was not present in the supernatant after centrifugation of coagulated semen, and it was degraded to several minor basic proteins when semen liquefied. These findings imply that the predominant seminal vesicle protein functions as the structural protein of coagulated semen. In much the same way as in ejaculated semen, the 52 kDa, 71 kDa, and 76 kDa protein bands in seminal vesicle secretion collected postmortem were digested to minor basic proteins after incubating the secretion with resuspended pellet from ultracentrifuged seminal plasma. This pellet contained the membrane-bound succinyl(alanine)3-p-nitroanilide hydrolysing peptidase of prostatic origin which, like the liquefaction process, was active in the presence of EGTA, inhibited by non-chelated Zn2+, and inactivated by o-phenanthroline--an inactivation that was reversed by Zn2+.

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.

Scanning electron microscopy and histological examination of human seminal plasma coagulum

Human seminal plasma coagulum was examined by S.E.M. and light microscopy using various preparatory techniques. Two types of structures were observed; porous and laminated. A consistent finding using all the preparatory techniques was the presence of the majority of the spermatozoa on the surface of the coagulum as opposed to the interior. Those spermatozoa present in the interior of the coagulum are attributed to the invagination of the surface layer. The presence of spermatozoa on the surface of seminal plasma coagulum plays an important role in concentrating spermatozoa in close proximity to the cervical os. This allows spermatozoa to reach cervical mucus rapidly and minimizes the time they must remain in the unfavourable environment of the vagina.

Use of Sputolysin form liquefaction of viscid human semen

A comparative study evaluating the effect of different mucolytic agents on viscid semen and on sperm motility at successive time intervals was carried out. Sputolysin (dithiothreitol, Calbiochem Behring, 1978) was found to be most efficient in liquefying viscid semen and also in preserving sperm motility. The mean liquefaction times for Sputolysin, Alevaire (a mucolytic detergent), and alpha-amylase were found to be 10 minutes, 39 minutes, and 20 minutes, respectively. The rate of decline in sperm motility over an interval of 24 hours was found to be least with Sputolysin, followed in order by phosphate-buffered saline, alpha-amylase, control, and Alevaire. The adverse effect of Alevaire on sperm motility over successive time intervals was quite marked. A serial dilution study with Sputolysin showed that, at higher dilution (1:80), liquefaction time was prolonged (24 minutes), but it was still shorter than with Alevaire (39 minutes) and nearly the same as with alpha-amylase (20 minutes).