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PubMed1992

Regulation of sulfated glycoprotein-2 (clusterin) messenger ribonucleic acid in the rat epididymis.

Sulfated glycoprotein-2 (SGP-2) is secreted by the principal cells of the caput epididymidis and binds to spermatozoa as they transit through this segment. The regulation of SGP-2 in the epididymis is poorly understood. The objectives of these studies were to determine if SGP-2 messenger RNA (mRNA) concentrations in the epididymis are regulated by testosterone or during postnatal development. Northern blot analysis was done using denatured plasmid containing a complementary DNA insert for rat SGP-2. A single 2.1-kilobase transcript was present throughout the epididymis. SGP-2 mRNA concentrations were highest in the caput followed by the initial segment, the cauda, and the corpus epididymidis. To determine if androgens regulate SGP-2 mRNA concentrations, adult rats were bilaterally orchidectomized and testosterone was replaced for 7 days using steroid-filled capsules measuring 2.5 or 18.6 cm. In the initial segment and the caput epididymidis, neither orchidectomy nor testosterone replacement, at either dose, had any effect on SGP-2 mRNA concentrations. In the corpus and cauda epididymidis, bilateral orchidectomy resulted in a 3.5- and 9.4-fold increase, respectively, in SGP-2 mRNA concentrations, whereas testosterone replacement caused a dose-dependent decrease in SGP-2 mRNA concentrations. Unilateral orchidectomy was done to determine if SGP-2 mRNA concentrations are dependent on testicular factors released in the lumen of the epididymis. In the corpus and the cauda epididymidis, unilateral orchidectomy resulted in elevated SGP-2 mRNA concentrations in the ipsilateral epididymis. There were no changes in SGP-2 mRNA concentrations in the initial segment and caput epididymidis. These results provide complementary evidence that the message for SGP-2 is differentially regulated along the epididymis. During postnatal development SGP-2 mRNA concentrations in the caput-corpus epididymidis increased dramatically between 14 and 21 days as well as between 49 and 63 days. Interestingly, between 28 and 42 days, when serum testosterone concentrations are increasing, there was no change in the concentration of SGP-2 mRNA in the caput-corpus epididymidis. Similar results were observed in the cauda epididymidis with the exception that between 28 and 42 days, there was a dramatic decrease in SGP-2 mRNA in the cauda epididymidis. Together these experiments demonstrate that the regulation of SGP-2 mRNA concentrations is segment specific. In the initial segment and caput epididymidis there is no apparent regulation of SGP-2 by testicular factors,whereas in the corpus and cauda epididymidis testosterone can repress SGP-2 mRNA concentrations.

Animals↗
PubMed1995

The segment-specific pattern of A-raf expression in the mouse epididymis is regulated by testicular factors.

The protooncogene homolog A-raf is expressed at high levels in a variety of steroid-responsive tissues and exhibits a highly regionalized pattern of expression in morphologically and functionally distinct segments of the mouse epididymis: the highest levels occur in the proximal caput, lower levels occur in the initial segment, and intermediate levels are found in the distal caput. Castration abolished detectable A-raf expression throughout the epididymis. The administration of exogenous androgens restored expression to precastrate levels, indicating that circulating, rather than intraluminal, levels of androgens are sufficient to maintain expression. Although overall levels of A-raf were maintained in androgen-replaced animals, the segment-specific pattern of expression was altered. Elevated levels of A-raf were expressed in the initial segment relative to those in controls. Coincident with this, the morphology of the epithelial cells in the initial segment of androgen-replaced castrates was altered to more closely resemble the morphology of proximal caput epithelial cells in controls. Similar increases in A-raf expression and changes in epithelial cell morphology relative to those in controls were observed in the initial segments of the castrate-side epididymis of hemicastrate mice, in epididymis from a germ cell-deficient strain of mutant mice, and in epididymis from intact mice supplemented with exogenous testosterone. These studies indicated that testicular products, such as spermatozoa, or substances that require germ cells for their production in the testis modulate the androgen-dependent expression of A-raf in the initial segment of the caput epididymis.

Androgen-Binding Protein↗
PubMed1999

Cellular immunolocalization of occludin during embryonic and postnatal development of the mouse testis and epididymis.

Cellular junctions in the testis and epididymis play crucial roles for the development and maturation of spermatozoa. In the testis, tight junctions between Sertoli cells form a functional blood testis barrier between 10 and 16 days of age, whereas the tight junctional blood epididymal barrier between adjacent epithelial cells is formed between days 18 and 21. In the present study, occludin, a constituent integral membrane protein of tight junctions, was localized by immunofluorescent confocal microscopy in embryonic (days 13.5-18.5), postnatal (days 5-23) and adult (day 70) mouse testes and epididymides to correlate its expression with the onset of tight junctions and eventual formation of these barriers. At embryonic days 13.5 and 16.5, low diffuse cytoplasmic levels of occludin were observed in cells of the testicular cords. By embryonic day 18.5, the level of occludin was still low but appeared as a filiform-like network streaming toward the center of the cord. At postnatal days 5 and 7 immunostaining became more intense and appeared to outline the periphery of Sertoli cells of seminiferous tubules. Postnatal day 14 marked the appearance of an intense, focal band-like localization of occludin at the base of the tubules, correlating with the appearance of a functional blood-testis barrier. By day 23 and in adults, expression of occludin was noted at the base of the tubule appearing as intense, wavy, discontinuous bands similar in appearance irrespective of the stage of the seminiferous epithelium cycle. In the developing epididymis, intense cytoplasmic immunostaining was present in epithelial cells of many epididymal tubules at embryonic day 13.5. By embryonic day 16.5, intense occludin immunostaining appeared along the lateral plasma membranes of epithelial cells, whereas at embryonic day 18.5, immunostaining was punctate and apically located, suggesting the presence of tight junctions by this age; similar immunostaining was noted at postnatal days 5 and 7. In the adult epididymis, distinct punctate apical staining was observed between adjacent principal cells of all epididymal regions except the proximal initial segment, where occludin was found only in association with narrow cells. These results indicate that in the epididymis, the appearance of occludin at apical sites between adjacent epithelial cells occurs during embryonic development suggesting that tight junctions form earlier than in the testis. While occludin was expressed in a similar pattern between Sertoli cells at all stages of the cycle in the adult testis, its expression in the adult epididymis was cell- and region-specific. Taken together these data suggest that different factors regulate occludin expression in the testis and epididymis.

Aging↗
PubMed1997

Gene expression of endothelin-1, endothelin-converting enzyme-1, and endothelin receptors in human epididymis.

We have previously reported the presence of endothelin-1 (ET-1) and its receptors in the human testis. In the present study we extended our investigations to human epididymis. The rationale of our study originated from the fact that sperm appear to be immotile during their transit through the epididymis. Hence, it is conceivable that specific factors, unknown to date, are present in this organ, capable of inducing smooth muscle contractions, thus forcing sperm transport. In this paper it is shown that ET-1 messenger ribonucleic acid and protein are readily detectable in the epithelial compartment of the human epididymis, and that ET-converting enzyme-1, which converts the precursor pro-ET-1 into the active peptide ET-1, is expressed in the epididymis, thus indicating an active processing of the prohormone. In addition, two classes of ET receptors were characterized and located in the muscle cells of the epididymis. These receptors correspond, in terms of affinity constants and capacity, to the ETA and ETB receptors previously characterized. These receptors mediate the contractile activity of the epididymis in vitro, thus suggesting that ET-1 can be responsible of sperm progression through this organ, acting via a paracrine mode of action.

Aged↗
PubMed2001

Cytochrome P450 aromatase in testis and epididymis of male rhesus monkeys.

To understand the role of estrogen in testicular and epididymal function of rhesus monkeys, we measured steroids in the spermatic and peripheral venus circulation and aromatase activity and its mRNA in testis and epididymis. Testosterone, estradiol-17beta, and estrone, but not androstenedione, were elevated in the spermatic vein serum compared to the peripheral circulation. Aromatase activity in testis and in caput epididymis (259+/-16 [SEM] vs 274+/-47 fmol of 3H2O/mg of protein/h [n = 10], respectively) was significantly higher (p < 0.01) than in corpus and cauda (124+/-28 and 113+/-33 fmol of 3H2O/mg of protein/h [n = 10], respectively). In the ribonuclease protection assay, two P450arom mRNA transcripts were identified in testis and epididymis. One corresponded with the aromatase full-length transcript and the other was a truncated isoform. The latter was significantly more abundant than the former (p < 0.01). Our results demonstrate that the monkey testis and, to a lesser extent, the epididymis can aromatize androgens. However, in the epididymis, like in some areas of the brain, there was a discrepancy between the aromatase activity and the mRNA. The fact that P450arom mRNA and aromatase activity do not correlate in the epididymis may indicate that aromatase activity is not strictly regulated at the level of RNA expression and that other mechanisms for this regulation should be considered.

Animals↗
PubMed1976

Free amino acids in the caput and the cauda epididymis of adult rats.

To examine the content and the composition of free amino acids in the intraluminal fluid of rat epididymis, the fluids were obtained by light pressure on the dissected tissues. The amount of the total free amino acids in the pressed fluid from the caput epididymis was significantly higher than those of the cauda epididymis and the testis. Glu and Gln were predominant amino acids in the caput, and their amounts occupied more than half of the total ninhydrin reactive compounds. Such a high concentration of Glu and Gln was not observed either in the cauda or in the testis. Castration decreased Glu and increased Gln in amount. Testosterone treatment to castrated animals did not restore Glu and Gln contents in the pressed fluid from the caput epididymis to the level observed in intact rats completely. Therefore, it was assumed that a large amount of Glu in the caput was due to many factors; secretion and metabolism of epithelial cells of the gland which might be regulated by androgen, inflow of rete testis fluid, and sperm metabolism of amino acids in the epididymis. The results obtained from the caput epididymis to which the efferent duct of the testis was ligated also supported this interpretation.

Amino Acids↗
PubMed1990

Effects of breeding season and mating on total number and distribution of spermatozoa in the epididymis of the brown marsupial mouse, Antechinus stuartii.

Changes in the number and distribution of spermatozoa in the epididymis of the adult brown marsupial mouse were examined during July/August in mated and unmated males. The effects of mating on epididymal sperm populations were studied in 2 groups of males each mated 3 times and compared with the number and distribution of spermatozoa in the epididymides of 4 unmated control groups. One testis and epididymis were removed from each animal (hemicastration) either before or early in the mating season to provide information on initial sperm content and distribution. The contralateral side was removed later in the mating season to examine the effects of mating or sexual abstinence on epididymal sperm distribution. Epididymal sperm number peaked in both the distal caput and distal corpus/proximal cauda epididymidis in late July. The total number of spermatozoa, including those remaining in the testis, available to each male at the beginning of the mating season in early August was approximately 4.4 x 10(6)/side. Although recruitment of spermatozoa into the epididymis from the testis continued until mid-August, sperm content of the epididymis reached a peak of about 3.5 x 10(6)/epididymis in early August. At this time approximately 0.9 x 10(6) spermatozoa remained in the testis which had ceased spermatogenic activity. Throughout the mating season, epididymal spermatozoa were concentrated in the distal corpus/proximal cauda regions of the epididymis and were replenished by spermatozoa from upper regions of the duct. Relatively few spermatozoa were found in the distal cauda epididymidis, confirming a low sperm storage capacity in this region. A constant loss of spermatozoa from the epididymis, probably via spermatorrhoea, occurred throughout the mating season and very few spermatozoa remained in unmated males in late August before the annual male die-off. Mating studies showed that an average of 0.23 x 10(6) spermatozoa/epididymis were delivered per mating in this species, but the number of spermatozoa released at each ejaculation may be as few as 0.04 x 10(6)/epididymis when sperm loss via spermatorrhoea is taken into account. We suggest that the unusual structure of the cauda epididymidis, which has a very restricted sperm storage capacity, may function to limit the numbers of spermatozoa available at each ejaculation and thus conserve the dwindling epididymal sperm reserves in order to maximize the number of successful matings which are possible during the mating season.

Animals↗
PubMed1992

Characterization of epidermal growth factor receptor in testis, epididymis and vas deferens of non-human primates.

The presence of the epidermal growth factor receptor (EGFR) in testis, epididymis and vas deferens of monkeys was demonstrated using a polyclonal antibody (RK2) raised against a peptide-specific sequence of the intracellular domain of the human EGFR. Immunoblotting of membrane preparations revealed a specific band at approximately 170 kDa corresponding to those of controls, A431 and monkey liver cells. Cryostat sections were stained by biotin-streptavidin peroxidase immunocytochemistry. The liver showed positive staining along the basolateral membranes of the hepatocytes lining the sinusoids. The testis showed positive staining indicating the presence of EGFR in Leydig cells, Sertoli cells and peritubular cells. In the epididymis, immunostaining of the EGFR was observed on both the basolateral and the luminal borders of the epididymal epithelium. Immunofluorescence studies revealed a similar pattern of EGFR distribution in the epididymis and indicated that the luminal immunostaining was vesicular. In the vas deferens, positive immunostaining was detected in a pattern very similar to that observed in the epididymis. There was no positive staining in the interstitium of the epididymis or in the smooth muscle cell layers of the vas deferens. The sections of all tissues treated with pre-immune serum were negative. These results suggest that EGF in the primate testis may act at the level of somatic cells. In addition, the basolateral and luminal EGFR staining in the epididymis and vas deferens suggest that these cells respond to an EGF, or EGF-like, source both at the basal, luminal or at both sides of the cells, or that these tissues serve as sites of EGF transcytosis across the epithelium.

Animals↗
PubMed2006

The region-specific functions of two ubiquitin C-terminal hydrolase isozymes along the epididymis.

We previously showed that gad mice, which are deficient for ubiquitin C-terminal hydrolase L1 (UCH-L1), have a significantly increased number of defective spermatozoa, suggesting that UCH-L1 functions in sperm quality control during epididymal maturation. The epididymis is the site of spermatozoa maturation, transport and storage. Region-specific functions along the epididymis are essential for establishing the environment required for sperm maturation. We analyzed the region-specific expression of UCH-L1 and UCH-L3 along the epididymis, and also assessed the levels of ubiquitin, which has specificity for UCH-L1. In wild-type mice, western blot analysis demonstrated a high level of UCH-L1 expression in the caput epididymis, consistent with ubiquitin expression, whereas UCH-L3 expression was high in the cauda epididymis. We also investigated the function of UCH-L1 and UCH-L3 in epididymal apoptosis induced by efferent duct ligation. The caput epididymides of gad mice were resistant to apoptotic stress induced by efferent duct ligation, whereas Uchl3 knockout mice showed a marked increase in apoptotic cells following ligation. In conclusion, the response of gad and Uchl3 knockout mice to androgen withdrawal suggests a reciprocal function of the two UCH enzymes in the caput epididymis.

Animals↗
PubMedDate not supplied

Anatomic aspects of epididymis and tunica vaginalis in patients with testicular torsion.

OBJECTIVE: To analyze the morphology of epididymis and tunica vaginalis as well as their anatomical anomalies in patients with testicular torsion. MATERIALS AND METHODS: We studied 25 patients (50 testes) aged between 12 and 23 years (mean 15.6). Torsion length ranged from 2 hours to 2 days (mean 8 hours). Epididymal anatomy was classified in 6 groups: Type I--epididymis united to the testis by its head and tail; Type II--epididymis totally united to the testis; Type III--disjunction of epididymal tail; Type IV--disjunction of epididymal head; Type V--total disjunction between testis and epididymis, and Type VI--epididymal atresia. The type of torsion was classified in 3 groups: Group A--intravaginal torsion; Group B--extravaginal torsion and Group C--torsion due to long mesorchium. RESULTS: Of the 50 analyzed testes, 40 (80%) presented bell clapper deformity (with 21 presenting intravaginal torsion); 8 testes (16%) had long mesorchium (4 with torsion), and only 2 (4%) presented normal anatomy in the tunica vaginalis. The most frequently found anatomical relationship between testis and epididymis was Type I--38 cases (76%); Type II relationship was found in 6 cases (12%) and Type III relationship was found in 6 cases (12%). CONCLUSIONS: Intravaginal torsion is the most frequent type, and torsion due to long mesorchium is associated with cryptorchism. The most frequently found anatomical relation between testis and epididymis in the study group was Type I.

Adolescent↗
PubMed1998

Is prolactin a gonadotrophic hormone in red deer (Cervus elaphus)? Pattern of expression of the prolactin receptor gene in the testis and epididymis.

This study investigated the pattern and site of expression of the prolactin receptor gene in the testis and epididymis of red deer collected during the breeding season (n=3). Ribonuclease protection assays using 50 microg total RNA and a 300 bp [32P]-labelled antisense cRNA probe, generated from the extracellular domain of the red deer prolactin receptor, confirmed the expression of the receptor in both the testis and epididymis; a higher level of prolactin receptor mRNA was detected in the epididymis compared with the testis (170.4+/-1.5 x 10(3) and 26.3+/-2.7 x 10(3) arbitrary units respectively; P<0.05). In situ hybridisation using 300 bp [33P]-labelled sense and antisense cRNA probes generated from the extracellular domain of the receptor localised the expression sites to the seminiferous tubules and interstitial compartments of the testis and the epithelial layer of the epididymal duct. Quantification of grain numbers demonstrated a higher level of expression of the receptor in the epididymis compared with the interstitial and seminiferous tubule compartments of the testis (18.1+/-4.4 x 10(2), 10.1+/-2.0 x 10(2) and 8.3+/-0.8 x 10(2) grains/microm2 respectively; P<0.05). However, no differences were detected in the level of expression of the receptor between the interstitial and seminiferous tubule compartments of the testis. Immunocytochemistry using an anti-prolactin receptor antibody, raised against a peptide sequence from the extracellular domain of the rat prolactin receptor, localised expression of the receptor gene to the Leydig cells, pachytene spermatocytes, round spermatids and elongating spermatids. In the epididymis, the receptor was localised to the epithelial layer within the epididymal ducts. Expression of the prolactin receptor gene in the red deer testis and epididymis suggests a role for the hormone in steroidogenesis and spermatogenesis.

Animals↗
PubMed2001

Novel androgen-dependent promoters direct expression of the C4b-binding protein alpha-chain gene in epididymis.

C4b-binding protein (C4BP) is a large plasma protein composed of seven alpha-chains and one beta-chain and is involved in the fluid phase regulation of the classical pathway of the complement system. Complement inhibitory activity is located in the alpha-chain, and its mRNA has been detected only in liver to date. Here, we have isolated cDNA clones encoding the alpha-chain of guinea pig C4BP (C4BP alpha) and have demonstrated significant C4BP alpha mRNA expression in epididymis as well as liver. The level of C4BP alpha transcripts increased in the epididymis after birth, while it remained constant in the liver. C4BP alpha mRNA was also detected in the normal murine epididymis at a significant level, but it decreased drastically after castration, suggesting that epididymal expression of the C4BP alpha gene is regulated by androgen. Gene analysis of guinea pig C4BP alpha indicated that liver and epididymis C4BP alpha mRNA share the coding region and 3'-untranslated region, but are transcribed from independent promoters on a single-copy gene. Two novel epididymis-specific promoters were identified in the region corresponding to the first intron of liver transcripts. The binding motif for hepatocyte NF-1 occurs in the promoter used for transcription of liver C4BP alpha, whereas androgen-responsive elements occur in both promoters used in the epididymis. These findings present a novel link between complement regulators and reproduction. Furthermore, variation in the 5'-untranslated regions, arising from alternative splicing of the newly identified exons, is demonstrable in the guinea pig C4BP alpha transcripts.

3' Untranslated Regions↗
PubMed1998

[Steroidogenesis in epithelial cells of rat epididymis].

Studies were performed on cultured epithelial cells of the caput and cauda of epididymis stemming from male rats of inbred Wistar strain. The cultures were conducted on a full medium enriched with 5% fetal calf serum in the presence or without exogenic androgens-T and DHT. The cells were identified by means of immunohistochemical reactions with the use of monoclonal antibodies against cytokeratin and desmin (Fig. 1, 2). All cells in the culture showed positive reaction to cytokeratin. At the same time there was a lack of desmin-positive cells. Through secreting the proteins, glycoproteins, glycolipids, phospholipids and number of other substances the epithelial cells of epididymis create an environment for maturating and storing of spermatozoa in lumen of the duct. Synthesis of these substances is possible thanks to the expression of genes defined for a given zone of epididymis, the expression being mainly regulated by androgen, although a share of estrogens is also evidenced in this process. The cytoplasm of epithelial cells of epididymis fails to reveal the presence of secretory granules, while the mechanism of releasing the secretion still continues to be controversial. There are also some and unverified suggestions about the capability of these cells to synthesize androgens. In connection with what was mentioned above, the objective of the work was to establish the mode of releasing the secretions by cultured epithelial cells of epididymis as well as to determine whether these cells synthesize androgens and if they may be the source of estrogens. Electron-microscopic observations disclosed a rich content of rough endoplasmic reticulum and structures similar to secretory units produced from concentrically arranged membranes encircling cytoplasm fragments in their interior (Fig. 10B, 14, 15A). There were protrusions of cytoplasm on the surface of cells. Released secretion was present between the cells. The apocrine way of releasing was confirmed also by scanning electron microscope. Numerous granular protrusions were released into the intercellular space (Fig. 19). The process of synthesis and release of secretion was androgen-dependent. Cells cultured without addition of exogenic androgens were characterized by disorganization of organelles and reduction of their number, particularly rough endoplasmic reticulum. The surface of cells was prevalently smooth, deprived from protrusions (Fig. 21). Very close neighbourhood, and sometimes a direct contact of lipid droplets and mitochondria with lamellar cristae as well as the presence of smooth endoplasmic reticulum observed in cytoplasm of cultured epithelial cells of epididymis, suggest their similarity to steroidogenic cells (Fig. 11A, 12). This is also indicated by the finding that these cells reveal the presence of active enzymes of the steroidogenesis pathway, 3 beta-HSD and 17 beta-HSD exhibited in histochemical reactions (Fig. 8, 9). RIA determination of hormones in the medium, wherein the epithelial cells had been cultured showed that the said cells synthesized and released DHEA, A and T, but in low and sometimes trace concentrations (Tab. 1-3). Lack of progesterone in medium of the cells on the 3rd and 5th days of culture indicates that the synthesis of testosterone and earlier forms of androgens proceeds using delta 5 metabolites, as it takes place in human testis. The cells' medium on the 3rd and 5th days of culture was found to disclose high concentration of 17 beta-estradiol (E2) (Tab. 4). E2 concentrations were always higher when the cells were grown without the addition of exogenic androgens. In this cases the cytoplasm of the cells displayed depolymerization of microtubules, which enhances the approximation to each other of structures participating in steroidogenesis and translocation of substrates and products of the consecutive stages of steroidogenesis. (ABSTRACT TRUNCATED)

Academic Dissertations as Topic↗
PubMedDate not supplied

Effects of short-term methylmercury exposure on metallothionein mRNA levels in the testis and epididymis of the rat.

Methylmercury (MeHg) is a widespread environmental contaminant that causes reproductive dysfunction in men. Metallothioneins (MTs) are low-molecular-weight proteins that can bind heavy metals and protect the cell from metal toxicity. MT levels are increased by exposure to metals and physiological stressors. Although MTs have been identified in the testis and epididymis, little is known about their distribution and regulation in the epididymis or the effects of MeHg on MT levels in male reproductive tissues. The objective of this study was to determine whether MT I, II, and III mRNA are present in the epididymis, if their relative levels differ between epididymal segments, and if MeHg alters cellular mRNA levels for MT I, II, and III in the testis and epididymal segments of the rat. Northern blot analysis was done on total cellular RNA isolated from each of the four epididymal segments (initial segment [IS], caput [CT], corpus [CS], and cauda [CA] epididymidis) using a cDNA probe for MT I and MT II. MT I transcripts were present in all epididymal segments. The lowest mRNA levels were observed in the IS; these levels were 4-fold less than in the CT and CS and 5.5-fold less than in the CA. MT II mRNA levels were similar in the IS and CT but were eightfold higher in the CS and CA. A cDNA probe for MT III was generated by reverse transcription-polymerase chain reaction using testicular RNA. MT III mRNA was detected only in the IS and CT and not in the CS and CA. To assess whether exposure to MeHg alters MT mRNA levels, rats were exposed for 14 days to one of five MeHg doses (0, 25, 50, 100, and 200 [microg/kg/day] via a subdermal osmotic pump. No changes were observed in either body weight or in the weights of the testis, epididymis, seminal vesicles, or ventral prostate between MeHg-treated and control rats. Serum testosterone levels were significantly decreased only at the highest MeHg dose. In the testis, MeHg treatment resulted in 2.5- to 7-fold increases in MT I mRNA levels. There were no changes in either MT II or MT III mRNA levels. In the initial segment of the epididymis, MT I mRNA levels were significantly increased only at the 50 microg/kg/ day dose, whereas there were no significant differences in MT II mRNA levels. In the caput epididymis, MT I mRNA levels were significantly lower at the 50 and 100 microg/kg/day dose. MT II mRNA levels were also lower, with the exception of the 50 microg/kg/day dose. Although MT III mRNA levels were lower at the two lower doses, levels were not different from controls in the two highest doses tested. In the corpus epididymidis, MeHg did not alter MT I mRNA levels, and MT II was higher only in the 50 microg/kg/day group. In the cauda epididymidis, MT I mRNA levels were decreased in a dose-dependent manner by up to 63%. MT II levels were unaltered. Together these data indicate that exposure of adult rats to MeHg can modulate MT mRNA levels in both the testis and epididymal segments. Furthermore, changes in MT mRNA levels following exposure to MeHg differ between epididymal segments, suggesting either differences in MeHg accumulation or differences in MT modulation.

Animals↗
PubMed1998

Development and use of surgical procedures to bypass selected regions of the mammalian epididymis: effects on sperm maturation.

Microsurgical procedures have been used to examine the function of selected regions of the epididymis. Vasoepididymostomy in the rabbit and rat confirmed that spermatozoa require some exposure to the epididymal environment for normal development of motility and fertilizing ability. In both of these species surgical redirection of spermatozoa from a region just distal to the initial segment into the vas deferens resulted in a significant reduction in sperm viability, motility and fertility compared with untreated animals. Surgical bypass of the distal cauda epididymidis in the rabbit did not significantly reduce the number of spermatozoa in ejaculates or the total sperm output accumulated during exhaustive ejaculations. The capacity of these bypass animals to store spermatozoa may be explained by the post-surgical formation of convolutions in the normally straight segment of the rabbit vas deferens. Vas autografts in the rabbit and rat were used to bypass selected epididymal segments. In rabbits, vascularized grafts were used as bridges to bypass the distal caput and proximal corpus epididymidis. Despite high rates of graft survival and patency in this species, the motility and viability of ejaculated spermatozoa were similar to those observed following high level vasoepididymostomy. In rats, non-vascularized vas grafts also showed a high survival and patency rate. There was a transitory reduction in sperm viability and motility 2 weeks after surgery which was associated with structural changes, especially in the epithelium, in vas bridge autografts during revascularization. Longer term observations (3 and 6 months) showed recovery of epithelial morphology and by three months after surgery, no difference was observed in sperm motility, sperm viability or fertility between experimental groups and controls. Similar results were obtained when epididymoepididymostomy was used as the surgical procedure to bypass the same regions of the epididymis. The evidence considered in this review clearly shows that the proximity of vasoepididymal bypass to the testis is inversely related to the state of maturity of ejaculated spermatozoa. More surprisingly, perhaps, it reveals that exposure of spermatozoa to the distal caput and proximal corpus regions of the epididymis in the rat is not obligatory for spermatozoa to develop a level of maturation in the remaining regions of the epididymis sufficient to ascend the female tract and fertilize ova. This finding suggests that the epididymis is more flexible in its functions than had been considered previously and that sperm maturation may not be as dependent on specific regional functions of the epididymis as had been previously proposed.

Anastomosis, Surgical↗
PubMedDate not supplied

Immunolocalization of NBC3 and NHE3 in the rat epididymis: colocalization of NBC3 and the vacuolar H+-ATPase.

In the male reproductive tract, the epididymis plays an important role in mediating transepithelial bicarbonate transport and luminal acidification. In the proximal vas deferens, a significant component of luminal acidification is Na+-independent, and mediated by specific cells that possess apical vacuolar proton pumps. In contrast, luminal acidification in the cauda epididymidis is an Na+-dependent process. The specific apical Na+-dependent H+/base transport process(es) responsible for luminal acidification have not been identified. A potential clue as to the identity of these apical Na+-dependent H+/base transporter(s) is provided by similarities between the transport properties of the epididymis and the mammalian nephron. Specifically, the H+/base transport properties of caput epididymidis resemble the mammalian renal proximal tubule, whereas the distal epididymis and vas deferens have characteristics in common with renal collecting duct intercalated cells. Given the known expression of the Na+/H+ antiporter, NHE3, in the proximal tubule, and of the electroneutral sodium bicarbonate cotransporter, NBC3, in renal intercalated cells, we determined the localization of NHE3 and NBC3 in various regions of rat epididymis. NBC3 was highly expressed on the apical membrane of apical (narrow) cells in caput epididymidis, and light (clear) cells in corpus and cauda epididymidis. The number of cells expressing apical NBC3 was highest in cauda epididymidis. The localization of NBC3 in the epididymis was identical to the vacuolar H+-ATPase. The results indicate that colocalization of NBC3 and the vacuolar H+-ATPase is not restricted to kidney intercalated cells. Moreover, the close association of the two transporters appears to be a more generalized phenomenon in cells that express high levels of vacuolar H+-ATPase. Unlike NBC3, NHE3 was most highly expressed on the apical membrane of all epithelial cells in caput epididymidis, with less expression in the corpus, and no expression in the cauda. These results suggest that apical NBC3 and NHE3 potentially play an important role in mediating luminal H+/base transport in epididymis.

Animals↗
PubMed2003

[A case of primary adenocarcinoma of the epididymis].

A 68-year-old man presented with right intrascrotal swelling. On palpation, a hard tumor without pain was recognized at the head of the right epididymis. Power Doppler ultrasonography revealed blood flow signals within the tumor. Surgical exploration was performed under the tentative diagnosis as possible malignant tumor of the epididymis. The right epididymis adhered to the testis so strongly, that the epididymis was resected with the testis. Pathological diagnosis was moderately differentiated adenocarcinoma of the epididymis. The results of general examinations on possible presence of primary lesions in other organs were all negative. Finally, the diagnosis of primary adenocarcinoma of the epididymis was obtained. He remains free of disease 17 months after surgery.

Adenocarcinoma↗
PubMed2004

Spatial and temporal expression of germ cell nuclear factor in murine epididymis.

AIM: To investigate the spatial and temporal expression of germ cell nuclear factor (GCNF) in mouse and rat epididymis during postnatal period. METHODS: The epididymal sections from different postnatal days were stained for GCNF by the indirect immunofluorescence technique and digital photographs were taken by a Carl Zeiss confocal microscope. RESULTS: GCNF was first detected on day 12 in mouse epididymis and day 14 in rat epididymis. The highest expression of GCNF was observed on day 35 in both mouse and rat epididymis. In adults, GCNF exhibited a region-specific expression pattern, i.e., it was expressed predominantly in the initial segment, caput and proximal corpus of rat epididymis and was abundant in the proximal corpus of mouse epididymis. GCNF could be found in the nuclei of the principal, apical, narrow, clear and halo cells. CONCLUSION: GCNF may play an important role in epididymal differentiation and development and in sperm maturation.

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