Electrolyte Composition of Rete Testis Fluid and Cauda Epididymal Plasma and Spermatozoa from Rats Following Gossypol Treatment

This investigation was undertaken to study the potassium and sodium concentrations in rete testis fluid and cauda epididymal plasma and spermatozoa following gossypol treatment. Rats were treated orally with gossypol acetic acid at a dose of 15 mg/kg/day for 3 and 6 weeks respectively. There were not abnormal findings in the ionic concentrations of cauda epididymal plasma following 3 or 6-week-treatment. After 6 but not 3 weeks the spermatozoa in the cauda epididymidis were rendered almost completely immotile and malformed with a significant reduction in their potassium concentration and rise in their sodium concentration. No abnormal findings in the morphological picture of the germinal epithelium were observed under such circumstances and fluid and sperm from the rete testis were normal. Therefore, a direct action of gossypol may be exerted locally on the spermatozoa in the epididymis.     

Acidification of epididymal fluid in the boar

The present study describes the measurement of pH made in vivo in the rete testis fluid and in different regions of the boar epididymis. Furthermore, samples of whole ejaculates, semen fractions, testicular (ductuli efferents/rete testis), epididymal and deferential fluids collected from the same fertile boars, were analysed for their acid/base status with an automatic blood gas analyser. A pH gradient of activity was found between the fluid entering the ductus epididymis (pH 7.2) and the region of sperm storage at the cauda (pH 6.5). A significantly lower concentration of bicarbonate ion was found in the cauda epididymidis (3-4 mM) compared to rete testis fluid (30 mM), which might be related to the quiescence of the spermatozoa. A significant increase in extracellular pH and bicarbonate concentration occurred at ejaculation, the bicarbonate levels being 9-10-fold higher in the semen fraction rich in seminal vesicle fluid, where sperm showed higher motility, than in the cauda epididymis.     

Epididymal Resorption of Spermatozoa in the Fild Rat (Millardia meltada)

A study has been made of epididymal resorption of spermatozoa in the field rat ( Millardia meltada ). At the height of its reproductive activity, many spermatozoa penetrate the epididymal epithelium and intertubular tissue where they undergo fragmentation and resorption. Sperm disposal is maximum in the cauda epididymidis.

Zusammenfassung

Auf der Höhe ihrer Reproduktionsaktivität dringen bei der Feldratte mehrere Spermatozoen in das Nebenhodenepithel und in das intertubuläre Gewebe ein, wo sie aufgelöst und resorbiert werden. Das Maximum der Spermatozoenbeseitigung liegt im Nebenhodenschwanz.     

Alterations in protein profile of rat spermatozoa during maturation

Alterations in the polypeptide pattern of rat spermatozoa during epididymal transit were studied by SDS-PAGE and compared with that of epididymal cytosol and luminal fluid. The total number of cytosol and luminal fluid polypeptides increase from caput to cauda epididymidis but sperm associated polypeptides decrease during epididymal transit. Changes in polypeptide pattern of spermatozoa are due to their acquisition, loss or modification. Spermatozoa acquire seven polypeptides, of which six are acquired in corpus (MW 16.5, 38, 41, 72, 75 and 100 Kdal) and one (MW 28.5 Kdal) in cauda epididymidis. Spermatozoa lose one polypeptide of MW 72.5 Kdal in caput and two polypeptides of MW 70 and 115 Kdal in cauda epididymidis. Four polypeptides of MW 18.5, 19.5, 64 and 67.5 Kdal disappear from cauda spermatozoa without appearing in the luminal fluid. Polypeptide of MW 62.5 Kdal is observed only in spermatozoa and luminal fluid from cauda epididymidis.     

The origin of some acid hydrolases of the fluid of the rat cauda epididymidis

The activity of N-acetyl-beta-D-glucosaminidase (NAG, 60.1 units/mg protein) and of acid phosphatase (57.7 units/mg protein) in fluid from the cauda epididymidis formed without any contribution from the testis (fluid obtained from a perfused and isolated cauda epididymidis or from an epididymis whose corresponding efferent ducts had been ligated for 40 days) was significantly higher than the activity of these enzymes in normal fluid (39.6 and 41.2 units/mg protein, respectively). Arylsulphatase activity of the locally formed fluid (11.2 units/mg protein) was lower than that of normal fluid (74.1 units/mg protein). The rete testis fluid was relatively rich in arylsulphatase since the ratio of arylsulphatase to acid phosphatase activity was 17 times higher in this fluid than in locally formed fluid. It is concluded that the activities of NAG and acid phosphatase in normal fluid from the epididymis originate in the epididymal tissue, while most of the arylsulphatase activity comes from the testis.     

Sperm structural and motility changes during aging in the Brown Norway rat

The Brown Norway rat provides a useful model to study aging of the male reproductive tract because of the selective age-dependent pathological changes that are found in the testis, epididymis, and prostate. In the testis, there is a clear age-dependent decrease in both steroidogenesis and spermatogenesis. In the epididymis, some striking segment-specific changes occur at the histological and biochemical levels prior to the major loss of spermatogenesis. We hypothesized that formation of spermatozoa in the testis and maturation of spermatozoa in the epididymis (ie, acquisition of motility and loss of the cytoplasmic droplet) may be altered during aging. Changes in the morphology of spermatozoa were assessed by light and electron microscopy. Using computer-assisted sperm analysis, the motility parameters of spermatozoa obtained from the caput and cauda epididymidis of young and old Brown Norway rats were compared. In old animals, we also compared the motility of spermatozoa from epididymides adjacent to regressed testes with those from epididymides adjacent to nonregressed testes. There was a marked increase with age in the number of spermatozoa with abnormal flagellar midpieces; the nature of these defects did not change with age. In caput epididymidis, the percentage of motile sperm was similar in young and old rats. In contrast, the percentage of motile spermatozoa was significantly decreased in cauda epididymidis of old rats; spermatozoa from the regressed testis side had altered motility characteristics. Furthermore, in the cauda epididymidis on the regressed testis side of aged Brown Norway rats, the proportion of spermatozoa that retained their cytoplasmic droplet was markedly elevated. Some of these effects are likely due to changes taking place in spermatozoa during the process of spermatogenesis in the testis (eg, formation of the flagellum), whereas others could occur during sperm maturation in the epididymis (eg, acquisition of motility). The multiple effects of aging on sperm morphology, the acquisition of motility, and the shedding of the cytoplasmic droplet clearly indicate that the quality of spermatozoa is affected by aging.     

The correlation between the gossypol contents in blood plasma, rete testis fluid, and cauda epididymal fluid following chronic treatment with gossypol in rats

Concentrations of gossypol in blood plasma, rete testis fluid, and fluid from the caudia epididymidis were measured simultaneously by high performance liquid chromatography in rats treated with gossypol (15 mg/kg daily for 3 weeks). Antispermatogenic effects were demonstrated by loss of sperm motility in the cauda epididymidis and structural changes in the testis. It was found in these treated rats that concentrations of gossypol were lower in rete testis fluid compared with blood plasma but increased significantly in fluid from the cauda epididymidis. The results indicate a restriction of the blood-testis barrier to gossypol and its local concentration in the epididymis after fluid resorption.     

Testicular and Epididymal Aldehyde Dehydrogenase in Rodents: Modulation by Ethanol and Disulfiram

The distribution of (newly found) NAD-dependent aldehyde dehydrogenase (ALDH) was determined in the rat testis and epididymis as a function of age. There were changes in specific activity of testicular ALDH as a function of age. Epididymal ALDH, which is found evenly distributed between the caput and cauda epididymis, increased initially from the 20th day after birth to the 50th day and remained little altered thereafter in both the caudet and the caput portion of the epididymis. Testicular and epididymal ALDH were found species-dependent with the hamster testis and the rat epididymis showing greater specific activities from the rest of the species studied, respectively. Determinations of testicular ALDH in various mouse strains indicate that it is strain-dependent. Intake of 25% (v/v) ethanol solution as the sole drinking fluid for 10 consecutive days inhibited testicular ALDH in the three mouse strains studied. Administration of disulfiram, 15 mg/kg/day for 60 consecutive days, exerted inhibitory action on testicular and epididymal ALDH in the rat. Intra-peritoneal injection of pyrazol, 100 mg/kg once daily for 7 days, resulted in inhibition of epididymal but not of testicular ALDH. It is suggested that testicular and epididymal ALDH may play a role in the toxic action of ethanol-derived acetaldehyde on the gonad.     

Alteration of epididymal function and its relation to maturation of spermatozoa

Alteration of epididymal function and its relation to maturation of spermatozoa was studied in 54 adult male albino rats. Levels of free and bound sialic acid in the spermatozoa and luminal contents of the epididymis and vas deferens were determined. A group of 10 received rabbit antiserum to ovine luteinizing hormone (LHAS) sc .2 ml/day for 5 days. 2 groups of 8 animals each received 2.5 mg cyproterone acetate twice daily for either 15 or 30 days. 16 animals served as intact controls and 12 animals served as castrate controls. Epididymis and vas deferens sperm counts were not affected by LHAS for 5 days or by cyproterone acetate for 15 days; however, sperm counts were decreased in the corpus (p less than .02), cauda (p less than .05), epididymidis and vas deferens (p less than .01) when rats were treated with cyproterone acetate for 30 days. Castration resulted in a marked reduction in all regions within 5 days. In the intact rats spermatozoa sialic acid decreased in the cauda epididymidis (p less than .01) and increased in the vas deferens (p less than .001). Sialic acid concentration was similar in those treated with either LHAS or cyproterone acetate for 30 days. Bound sialic acid in the epididymal fluid increased (p less than .02) to a maximum in the corpus and cauda and decreased in the vas deferens (p less than .05). LHAS or cyproterone acetate caused a reduction in bound sialic acid in the fluid of the epididymis and vas deferens.     

Zinc Content in Epididymal Spermatozoa of Metoclopramide-Treated Rats

Zinc content was determined separately in spermatozoa taken from epididymal caput and cauda in rats. It was revealed that spermatozoa transported from the epididymal caput to the cauda reduce about 54% of zinc. This reduction is significantly inhibited in spermatozoa of rats receiving metoclopramide. That is also accompanied by a fall of testosterone level in blood serum and of delta 5, 3 beta-HSD activity in Leydig cells. It was found out that the reduction of zinc in spermatozoa at the time of their passage through the epididymis is the process that depends on androgens.     

大鼠精子在附睾成熟过程中肉毒碱量变化的研究

肉毒碱被认为是与精子在附睾中成熟有关的成熟因子。本文报告测定大鼠附睾头部,体部及尾部精子中的肉毒碱。结果表明精子在循附睾头、体、尾运行过程中,精子中肉毒碱含量逐步增加,在附睾体一头部,附睾尾一头部的精子内的肉毒碱量呈现十分显著性差异。结果提示附睾体部或体一头部交界部位可能是精子在附睾中成熟的关键部位。     

Decreased fertility and motility of spermatozoa from rats immunized with a prealbumin epididymal-specific glycoprotein

This study investigated the effects on the progressive motility, zona-binding capacity, and fertility of spermatozoa from the cauda epididymidis of adult male rats that were actively immunized against an acidic glycoprotein secreted by the epididymis. The percentage of motile spermatozoa was less than 5% in nine of ten rats that received the epididymal antigen, and 40 to 50% in eight of the 10 control rats. In animals immunized against the antigen, there was a dramatic decrease, but not a complete suppression, in the capacity of epididymal spermatozoa to bind the zona pellucida as compared with the nonimmunized controls. Fertility was decreased two weeks after the end of the treatment, but partial restoration of fertility was observed 6 months later.     

Functional role of hepatocyte growth factor receptor during sperm maturation

Mammalian spermatozoa acquire motility and fertilizing capacity during their transit through the epididymis. Hepatocyte growth factor (HGF) is a pleiotropic cytokine with potent motogenic capacities that has been identified in different organs, including the mammalian male genital tract. In mice, HGF is present in the testis and, in large amounts, in the distal part of the epididymis. In prepuberal rats, we have demonstrated that HGF is synthesized by the peritubular myoid cells and in men, HGF is present in significant quantities in seminal plasma. It has been suggested that in mice, HGF has a role in initiating sperm motility, whereas in men, no significant correlations between HGF concentration and sperm motility have been found. In the present paper we report that in rats, HGF receptor, c-met, is expressed in testicular and epididymal spermatozoa. Through immunocytochemistry, we have found that c-met is exclusively localized on the head in testicular sperm. A different localization of c-met has been found in sperm isolated from caput and cauda epididymidis. Cells isolated from epididymal caput show a c-met localization exclusively restricted to the head in most cells. In a minority of caput epididymis spermatozoa the receptor is localized both in the cell head and along the flagellum. Spermatozoa isolated from the epididymal cauda were quite homogeneous, showing the receptor localized along the entire cell surface. We also report that HGF is synthesized and secreted by the rat epididymis as indicated by the scatter effect of epididymal cell homogenate and culture medium on MDCK cells. To clarify whether HGF is involved in the acquisition of sperm motility in the epididymis, its maintenance, or both, spermatozoa isolated from caput epididymidis have been cultured in medium alone or supplemented with HGF. The results obtained indicated that HGF has a positive effect on the maintenance of sperm motility which, in the absence of HGF, significantly decreases during the first hour of culture, whereas it is maintained for at least 3 hours when HGF is present in the culture medium. We also report that HGF does not influence spermatozoa viability as indicated by the cytometrical analysis of propidium iodide-labeled sperm; an equal number of dead cells appeared in control and in HGF-treated preparations. In conclusion, our data strongly support the hypothesis that HGF positively influences sperm motility maintenance during sperm transit through the epididymis, indicating that c-met receptor and its ligand, HGF, have a role in male fertility.     

Origin of the luminal fluid proteins of the rat epididymis

Using a combined microperfusion and high resolution gel electrophoresis technique, the origin of the epididymal fluid proteins of the rat has been investigated. Some proteins originate from the testis, others are secreted by the epididymis or are released by spermatozoa. Of particular interest is a 32 000 dalton protein found to be actively secreted by the caput epithelium in situ and concenrated in the lumen. The cauda epididymidis contained the highest concentration of this protein. Radioactive labelling of the sperm surface proteins revealed that this protein was present on the surface of the mature cauda but not on the immature caput or corpus sperm, suggesting its acquisition by the sperm surface during epididymal transit. Another sperm surface protein of interest (MW 40 000) is present only on the plasma membrane of the cauda but not on that of the caput or corpus sperm. Since this protein was not identified in the epididymal perfusates or luminal fluids, its presence may result from some modification events taking place in the sperm membrane during maturation.     

Quantitative （stereological） study on the spermatozoal storage capacity of epididymis in rats and monkeys

Aim: To investigate the spermatozoal production rate of the testis and the spermatozoal storage capacity of the epi-didymis in monkeys and rats. Methods: The number of the late spermatids (steps 13 - 14 in the monkey or steps15 - 19 in the rat) per testis and the number of spermatozoa per epididymis were estimated in 6 normal adult monkeys(Macaca fascicularis) and 6 normal adult SD rats on 25 um-thick methacrylate-embedded sections using a contempo-rary unbiased and efficient stereological method-the optical disector. The diameter and length of the efferent ductulesand ductus epididymidis and the volume of the epididymal fluid in the tubules were also estimated. Results: The totalnumber of the late spermatids per testis was 2902 ±749 (million, x ±s) in the monkey, or 179 ±31 in the rat; thenumber of spermatozoa per epididymis was 3235 ±1835 in the monkey, or 241±76 in the rat. Conclusion: A largenumber of spermatozoa was densely packed and stored in the ductus epididymidis; the epididymal transit t     

Changes in surface protein structure of bull spermatozoa during epididymal maturation

The surface proteins of bull spermatozoa from caput and cauda epididymidis were labelled by lactoperoxidase-catalyzed radioiodination and solubilized and analysed by SDS-PAG-electrophoresis. The surface protein patterns of caput and cauda epididymal spermatozoa resembled each other but some distinct differences could be found. Caput epididymal spermatozoa revealed a protein peak with molecular weight of 15 000 - 18 000 daltons but this peak was not found on cauda epididymal spermatozoa. On caput epididymal epermatozoa the most intensely labelled protein peak was located between 90 000 and 100 000 daltons but on cauda epididymal spermatozoa the corresponding peak was only weakly labelled and had a molecular weight of 80 000–90 000 daltons. Surface protein with molecular weight of 42 000–47 000 daltons was dominating on cauda epididymal spermatozoa. The surface protein structure of cytoplasmic droplets did not drastically differ from that of epididymal spermatozoa.     

Gamma-glutamyl transpeptidase activity in the epididymis during fetal and postnatal development in rats.

The histochemical and biochemical distributions of gamma-glutamyl transpeptidase (gamma-GT) were investigated in the epididymis of rats during fetal and postnatal development. In the epididymal homogenates, gamma-GT activity was detected on the fifth day after birth. A sharp increase was observed after 30 days of life in the caput homogenates. Moderate levels of the enzyme were found in the cauda epididymis. Gamma-GT is histochemically detected from the 15th day of gestation in Wolffian ducts and in 17- to 18-day-old fetuses in newly differentiated epididymal tubules. Enzyme activity, was associated with the plasma membranes (apical, lateral, and basal), was preponderant on the apical part of the epithelial cells. During the first 15 days of the postnatal life, the histochemical reaction intensities were identical from the caput to the cauda epididymidis. From the 18th day onwards, enzyme activity decreased in the corpus and in the cauda, while gamma-GT increased in the caput epididymidis, and a strong activity was found on the apical surface of epithelial cells. Weak or moderate gamma-GT activity of spermatozoa in the caput tubules, increasing steadily from caput to cauda epididymidis, suggests that gamma-GT may be related to the functional maturation of spermatozoa.     

Sperm protamine levels as indicators of fertilising potential in sexually mature male rats

We have earlier reported that administration of cyproterone acetate, fluphenazine decanoate, tamoxifen citrate, oestradiol valerate to adult male rats, at doses of 50, 5.77, 0.71, 0.28 micromol kg(-1) body weight given for periods of 15, 60, 60, 10 days, respectively, partially suppressed/reduced availability of one or more reproductive hormones viz. LH, FSH, testosterone and reduced their siring ability. The reduction in epididymal sperm counts was not considerable after treatment with these drugs, but conventional methods of assessment of spermatozoa quality viz. sperm chromatin structure assay (SCSA), nuclear chromatin decondensation (NCD) assay, monobromobimane (mBBr) uptake, had shown quantifiable changes in caput sperm chromatin compaction and reduced the testicular levels of protamine 1. The present follow-up study attempts to quantify changes in caudal sperm chromatin which has undergone compaction in the epididymis, in the altered hormonal microenvironment of rats treated with cyproterone acetate, tamoxifen citrate, fluphenazine decanoate, oestradiol valerate, at doses of 50, 5.77, 0.71, 0.28 micromol kg(-1) body weight respectively given for periods of 15, 60, 60, 10 days, with a view to correlating these changes to reduction in their fertilising potential. During the androgen-dependent transit of spermatozoa from caput to cauda epididymis, thiol group oxidation and tyrosine phosphorylation of protamine occurs in maturing sperms concomitant with development of fertilising ability. The results indicate that conventional methods viz. SCSA, NCD, mBBr uptake fail to detect changes induced by hormone deficits in sperm chromatin condensation, as a result of maturation during transit from caput to cauda epididymis. Absence of protamine 1 in epididymal sperm was observed in either testosterone or FSH deficient rats that correlated with reduced fertilising potential. The study suggests that changes in LH/T or FSH affect a hitherto unknown common molecular mechanism in the testis, underlying the protamination of rat spermatozoa. In conclusion, loss of P1 occurs in adult male rats deprived of T or FSH and is a reliable detectable change in epididymal sperm indicative of chromatin condensation defects associated with endocrine imbalance and poor fertility status.     

Secretion of macromolecules by the rat epididymis

Sperm maturation in the rat epididymis is dependent on the secretion of specific proteins by the epididymal epithelium and subsequent interaction of these proteins with spermatozoa. Evidence has shown that fertility and motility development of epididymal spermatozoa may be impaired by interfering the interaction of these proteins with spermatozoa. When the spermatozoa reach the cauda epididymidis, they are fully mature but their longevity is maintained by being stored in a quiescent state in the cauda. The unique ionic medium therein (low Na⁺, low Ca²⁺, high K⁺ and low pH) suppresses sperm motility and hence reserving energy for the vital processes of capacitation and fertilization. During ejaculation, when the spermatozoa are mixed with the copious secretion from the accessory glands they burst into vigorous motility. This results from an influx of sodium coupled to efflux of K⁺ and H⁺ across the mature sperm membrane. In the presence of a peptide secreted by the cauda epididymidis, these ionic events activate the already mature but otherwise inactive spermatozoa to full motility.     

The ultrastructure of dog epididymis

Summary The ultrastructure of the epididymal duct and ductuli efferentes in the dog has been studied by electron microscopy. The epididymidis can be separated into the classical divisions of caput, corpus and cauda epididymidis on the basis of general morphology and ultrastructure. The ductuli efferentes have a low epithelium with pronounced cilia at the apices of cells and appear to provide primarily a transport role for spermatozoa. In the epididymis proper the caput region is characterized by an extremely large Golgi apparatus with large numbers of lysosomes and nuclear inclusions. Secretory activity appears to be most common in the corpus region. Absorption and secretion are most active in the first two segments while in the cauda epideidymidis the long-term storage of spermatozoa in the lumen is associated with many dense crystalline bodies formed in the epithelial cells within the Golgi apparatus and possibly deriving from absorbed macromolecular material from the lumen. The theory of whole sperm cell resorption by the epididymal duct is not supported by this study.