Seminal Fractions Research Articles

Peptidase activities in human semen

Enkephalins are one of the opioids present in human semen and to date their function in this tissue remains unknown. The present work studies enkephalin-degrading enzyme activities, puromycin-sensitive alanyl aminopeptidase (AAP-S), puromycin-insensitive alanyl aminopeptidase N (Ap N) and neprilysin (NEP) in human seminal fractions. AAP-S activity was not detected in any fractions, whereas Ap N appeared in soluble and particulate sperm fractions in seminal fluid and in prostasome fraction. With regard to NEP activity, this was exclusively located in prostasome membranes. The high activity values observed in the prostasome fraction suggested that these peptidases and their substrates could be involved in seminal physiology.

Effect of split ejaculation and seminal extenders on longevity of donkey semen preserved at 5° C

The aim of this study was to evaluate the longevity of donkey sperm comparing the rich seminal fraction and the whole semen in two extenders, Kenney and modified Baken extenders. Semen of five donkeys were collected through an open-end artificial vagina once a week for five consecutive weeks. The two first jets (rich fraction) of semen were collected separately from the rest of the ejaculate. Whole semen samples were obtained mixing proportionally part of the rich with part of the poor seminal fractions. Seminal samples were immediately diluted 1:1 in each extender and maintained at room temperature during sperm concentration analysis. Samples were further diluted to rich 50×10(6) sperm per ml, cooled in a refrigerator at the initial rate of -0.6° C/min and preserved at 5° C. Total motility (TM), progressive motility (PM) and sperm vigor (V) were examined after final dilution and cooling, and every 24 hours up to the decrease of total motility under 10%. Sperm morphology was evaluated using a phase contrast microscope directly after dilution, on days 3, 6 and 9 post collection. It was used a 2×2 factorial design in a randomised bloc experiment, and means were compared by Student’s t test. Longevity did not vary between the rich seminal fraction and the whole semen for both extenders used. TM, PM, V and sperm morphology were better preserved in the extender with egg yolk (modified Baken extender) than in the one with skimmed milk (Kenney) in both seminal fractions.

Age-related changes in plasma testosterone concentrations and genital organs content of bulk and trace elements in the male dromedary camel

There is a paucity of information regarding the influence of plasma testosterone concentrations and inorganic cations secreted in the different seminal fractions on the spermatozoon activity throughout the reproductive life of the one-humped camels. To demonstrate these relationships, the genital organs of 12 prepubertal (<3 years), 9 peripubertal (3–<5 years), 16 mature (5–<15 years) and 15 aged (≥15 years) camels were collected from the Buraidah slaughter house (Al-Qassim Province, Saudi Arabia) during two consecutive breeding seasons (November–April) over 2 years. Plasma testosterone concentrations (mean±S.E.) did not exceed 1.4 ng/ml in prepubertal animals with a 3–4 fold increase in peripubertal (3.2±0.4 ng/ml) and mature (4.8±0.6 ng/ml) camels followed by about 50% decrease (2.6±0.3 ng/ml) in aged ones. These hormonal changes were correlated significantly with concentrations of certain elements in the testes (highest Na, Ca and Cu contents), epididymides (highest P and Fe contents), prostrate (highest Zn content), and bulbo-urethral glands (highest K and Mg contents). The significance of some interrelationships among the different cations and their biological effects on sperm production and metabolic activity were discussed.

Oxytocin in the semen and gonads of the stallion

It has been suggested that oxytocin is involved in sperm transport and motility in domestic animals. Immunoreactive oxytocin was measured in seminal fractions (pre-ejaculatory fluid, seminal plasma, gel and sperm) and in extracts of testis and epididymis from stallions. In addition, sections of gonadal tissue from stallions were immunostained for the presence of oxytocin and its neurophysin. Oxytocin was detected in all of the seminal fractions, being highest in the gel. It was also present in washed, lysed sperm and in extracts from the testis and epididymis. Immunostaining for oxytocin was present in occasional interstitial cells in the testis and in the epididymal epithelium and smooth muscle. However, immunostaining for neurophysin was detected in a few interstitial cells in the testis of only 1 of 8 stallions and was absent from all areas of the epididymis. These data demonstrate for the first time the presence of oxytocin in stallion semen and gonadal tissue; however, lack of immunostaining for neurophysin indicated that it was unlikely that there was local synthesis within the gonads.

Absence of hepatitis C virus and detection of hepatitis G virus/GB virus C RNA sequences in the semen of infected men.

The identification of hepatitis C virus (HCV) in semen remains controversial and that of hepatitis G virus (HGV) or GB virus C (GBV-C) has never been investigated. Serum and semen from 90 anti-HCV-positive drug users were tested (27 infected with HIV) for HCV and HGV/GBV-C RNAs by polymerase chain reaction (PCR) assay, hybridization, and sequence analysis. Semen was processed into round cells, seminal plasma, and spermatozoa. Fifty-six patients were HCV-viremic, but HCV-RNA was not identified in their seminal fractions. However, PCR inhibitors were found in the semen of 34 of these men. Twenty-eight patients had HGV/GBV-C RNA in their blood and for 24 of them, ejaculates were available for analysis. HGV/GBV-C RNA was found in the seminal plasma of 6 of 12 samples free from PCR inhibitors. These results agree with the low risk of sexual transfer of HCV and provide preliminary evidence for the presence of HGV/GBV-C in semen.

Distribution of Pz-peptidase in bovine epididymal and ejaculated semen.

Bovine epididymal or ejaculated semen was fractionated by density gradient centrifugation in Percoll, and seminal components recovered from the gradients were subjected to additional separation and washing steps. This procedure resulted in isolation of four major seminal constituents: particle-free extracellular fluid, washed light particulates, washed cytoplasmic droplets, and washed spermatozoa. When assayed using the Pz-peptide substrate, all the isolated seminal fractions contained substantial Pz-peptidase activity. The extracellular fluid Pz-peptidase was present in soluble form, but Triton X-100 was required for complete extraction of the Pz-peptidase activity from the spermatozoa, cytoplasmic droplets, and light particulates. The greatest Pz-peptidase activities were observed in the cytoplasmic droplet and epididymal sperm extracts, whereas the activities in extracellular fluid, extracts of light particulates, and extracts of ejaculated spermatozoa were relatively low. Most of the Pz-peptidase activity in extracts of epididymal spermatozoa was attributable to cytoplasmic droplets. The specific Pz-peptidase activities found by regression analysis were 6.1 mU/billion attached cytoplasmic droplets and 1.1 mU/billion spermatozoa. These results established that in the bovine, cytoplasmic droplets were the major source of Pz-peptidase activity in semen and that Pz-peptidase was not primarily a spermatozoal enzyme.

Human Intra-urethral Inoculation of Ureaplasmas

Ureaplasma urealyticum was isolated from two men suffering from non-specific urethritis and from whom no other micro-organisms were recovered. Their disease responded to tetracycline. The two ureaplasma strains were cloned and shown to belong to serotype 5 of U. urealyticum . An inoculum containing 5×104 colour-changing units of one strain was introduced intraurethrally into a subject (an author) who was free of ureaplasmas and other urethral micro-organisms. The ureaplasmas multiplied in the urethra and the subject soon experienced symptoms of dysuria. Furthermore, polymorphonuclear leucocytes were found in centrifuged aliquots of urine and a serum metabolism-inhibition antibody response of short duration was detected. Tetracycline given six days after inoculation brought about rapid clearance of organisms from the urine and a more gradual disappearance of symptoms and signs. Inoculation of ureaplasma-free medium about two months after the initial introduction of ureaplasmas did not elicit symptoms or signs. These observations showed that the ureaplasmas had produced urethritis. Organisms of the other ureaplasma strain were introduced in the same number and in the same way into a second subject (another author) who was also free of urethral micro-organisms. He experienced symptoms and signs similar to the first subject, ureaplasmas were consistently isolated from urine and a serum antibody response of at least three months duration was detected. However, the characteristic feature was the appearance of urinary threads composed of epithelial cells and polymorphonuclear leucocytes. Following tetracycline therapy instituted one month after inoculation, viable ureaplasmas were rapidly eliminated from the urogenital tract and, although most signs disappeared, urinary threads continued to appear. Inoculation of ureaplasma-free media over two months after the initial challenge elicited some symptoms and signs, but these were less than those which occurred after introduction of ureaplasmas. Analysis of seminal fractions during the course of the ureaplasma infection indicated that the prostate was infected. The possibility that the threads were of prostatic origin and the reason for their persistence are discussed.