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.     

γ-Glutamyl transpeptidase in rat epididymis: effects of castration, hemicastration and efferent duct ligation

Gamma-Glutamyl transpeptidase (gamma-GT) was studied histochemically and biochemically in the rat epididymis after castration with or without testosterone treatment, or after hemicastration and ligation of the efferent ducts. There was a strong reaction to gamma-GT in the apical part of the epithelium in the caput epididymis, while in the corpus and cauda the reaction was confined mainly to the luminal contents. Castration caused a marked decline in epithelial gamma-GT activity within 10 days. Subsequent testosterone treatment (1 mg/day for 10 days) restored gamma-GT activity in the apical surface and lumen. After hemicastration of adult rats, and after hemicastration or ligation of the efferent ducts in immature 28-day-old rats, a small but significant (P less than 0.001) decrease was observed in gamma-GT activity in the epididymal caput compared to controls. The quantities of six other enzymes (beta-N-acetylglucosaminidase, beta-galactosidase, angiotensin-converting enzyme, alanyl amino-peptidase, dipeptidyl peptidase IV, acid phosphatase) also displayed significant changes after castration and restoration of activities by testosterone treatment. However, their distribution in the caput and cauda epididymis was more even than that of gamma-GT, and the changes after castration were less drastic. It is concluded that gamma-GT is a highly sensitive androgen-dependent secretory marker in the caput epididymis and may have an important function in sperm maturation.     

Secretion of glycosidases in human epididymal cell cultures

The dynamics of glycosidase secretion was evaluated in human epididymal cell culture. Epithelial cells from caput, corpus, and cauda epididymis were isolated from tissue obtained from patients undergoing therapeutic orchidectomy due to prostatic carcinoma. The activities of alpha-glucosidase, N-acetylglucosaminidase, beta-glucuronidase, and alpha-mannosidase were analyzed in conditioned culture media. Glycosidase activity was significantly higher in corpus and/or cauda than in caput epididymis. There was a time-dependent increase in enzyme activities that was maximal between 10 and 14 days of culture in all epididymal regions. Epididymal glycosidases are secreted by cultured epithelial cell from human epididymis with an increase toward the distal regions of this organ, which may be related to the dynamics of sperm maturation. Cultures from different epididymal regions may represent a valuable tool to study of human epididymal function.     

Effect of bisphenol A and co-administration of bisphenol A and vitamin C on epididymis of adult rats： A histological and biochemical study

Aim: To study the effect of bisphenol A on the epididymis and epididymal sperm of rats and the possible amelioration action of co-administration with vitamin C. Methods: Male Wistar rats were orally administered bisphenol A (0.2 μg·kg-1·day-1, 2 μg·kg-1·day-1 and 20 μg·kg-1·day-1) and 0.2 μg, 2μg and 20 μg bisphenol A + 40 mg vitamin C·kg-1·day-1 for 60 days. On day 61, rats were killed with anesthetic ether and sperm collected from epididymis were used for assessment of sperm count, motility and viability and biochemical studies. A 1 % homogenate of epididymis was prepared and used for biochemical estimations. Caput, corpus and cauda epididymis were fixed in Bouin's fixative for histological studies. Results: Administration of bisphenol A caused a reduction in the epididymal sperm motility and count and the sperm viability remained unchanged. The activities of superoxide dismutase and glu-tathione peroxidase decreased, while the levels of lipid peroxidation increased in epididymal sperm an     

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。     

Erratum

During passage of hamster spermatozoa through the epididymis their maturation is shown to involve changes in the sperm head, midpiece (mitochondria) and tail. The sum of these changes results in a dramatic increase in the fertilizing potential of the spermatozoa. When comparable numbers of spermatozoa from the caput or corpus epididymis were injected into one uterine horn of mature females, following ovulation induction, and spermatozoa from the cauda epididymis were injected into the contralateral horn, no fertilization was observed with caput epididymal spermatozoa, 1.7% of oocytes were fertilized by corpus epididymal spermatozoa, whereas 79.5% fertilization was obtained with cauda epididymal spermatozoa. Total sperm numbers increased from caput to corpus to cauda [28.3 ± 12.2, 40.6 ± 20.8, 144 ± 62 million, respectively]. The percentage of progressively motile spermatozoa increased from 27.9 ± 6.4 to 33.8 ± 4.8 to 70 ± 10.7 during this passage. Viability, measured by exclusion of the dye, propidium iodide, was significantly less in spermatozoa from the cauda than from the proximal or mid-caput epididymis. The percentage of the live cells that were stained intensely by rhodamine-123 (a measure of mitochondria1 membrane potential) increased during epididymal passage from 22.8 ± 7.8% in the proximal caput epididymis to 57.2 ± 16.5% in the cauda epididymis. Staining with acridine orange (a measure of DNA packaging in the sperm head) indicated an increase in chromatin condensation in cauda epididymal spermatozoa, when compared to those obtained from the caput or corpus.     

Investigation of epididymal sperm maturation in the golden hamster

During passage of hamster spermatozoa through the epididymis their maturation is shown to involve changes in the sperm head, midpiece (mitochondria) and tail. The sum of these changes results in a dramatic increase in the fertilizing potential of the spermatozoa. When comparable numbers of spermatozoa from the caput or corpus epididymis were injected into one uterine horn of mature females, following ovulation induction, and spermatozoa from the cauda epididymis were injected into the contralateral horn, no fertilization was observed with caput epididymal spermatozoa, 1.7% of oocytes were fertilized by corpus epiddymal spermatozoa, whereas 79.5% fertilization was obtained with cauda epididymal spermatozoa. Total sperm numbers increased from caput to corpus to cauda [28.3 ± 12.2, 40.6 ±20.8, 1434 ±62 mihon, respectively]. The percentage of progressively motile spermatozoa increased from 27.9 ±6.4 to 33.8 ± 4.8 to 70 ± 10.7 during this passage. Viability, measured by exclusion of the dye, propidium iodide, was significantly less in spermatozoa from the cauda than from the proximal or mid-caput epididymis. The percentage of the live cells that were stained intensely by rhodamine-123 (a measure of mitochondrial membrane potential) increased during epididymal passage from 22.8 ±7.8% in the proximal caput epididymis to 57.2 ± 16.5% in the cauda epididymis. Staining with acridine orange (a measure of DNA packaging in the sperm head) indicated an increase in chromatin condensation in cauda epididymal spermatozoa, when compared to those obtained from the caput or corpus.     

Androgen Dependence of Testicular and Epididymal Angiotensin Converting Enzyme

Treatment with cadmium chloride (CdCl2) and cyproterone acetate (CA) depressed angiotensin converting enzyme (ACE) activity significantly in testes and epididymal regions of the adult rats compared to the corresponding untreated controls. Exogenous testosterone to CA-treated rats significantly increased the enzyme activity both in the testes and epididymis, the effect in the latter being very significant comparable to CA-treated and untreated controls. Testosterone failed to induce ACE activity in the testes and caput epididymis of 30 day-old immature rats, but the enzyme activity was detected in corpus and cauda epididymis. Our findings indicate that ACE activity in the testicular complex is possibly linked with androgen and is concerned with spermatogenesis and sperm maturation.     

Effect of thyroxine treatment on epididymal carbohydrate metabolism in the pubertal rat

The influence of thyroxine treatment on key enzymes involved in the glycolytic and HMP shunt pathways was studied in the caput, corpus and cauda epididymides of pubertal rats, and related to the serum hormone profile. The activity of 6-phosphofructokinase and pyruvate kinase was significantly increased in all 3 segments of the epididymis, but the HMP shunt pathway was suppressed. Thyroxine treatment was found to depress the serum levels of testosterone, LH and FSH, although an increase in prolactin levels was observed. Withdrawal of hormone treatment resulted in the restoration of normal activity of 6-phosphofructokinase and pyruvate kinase and restoration of normal serum hormone levels. However, the activity of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase increased following withdrawal of treatment. It is concluded that hyperthyroidism exerts an influence on epididymal enzymes involved in carbohydrate metabolism.     

Two-dimensional gel electrophoretic analysis of rat sperm membrane interaction with cauda epididymal fluid

Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) was used to analyze the polypeptide composition of rat cauda epididymal fluid, blood serum and membrane-enriched fractions of caput, corpus, and cauda epididymal spermatozoa. Several polypeptides were found in both cauda fluid and blood serum, and in both cauda fluid and epididymal spermatozoa. Prominent cauda epididymal fluid polypeptides that were associated with caput, corpus, and cauda sperm membranes were 32 and 33 kDa. Passage of spermatozoa from the caput to the cauda epididymidis was characterized by the loss of three glycopolypeptides of 32, 30 and 29 kDa, and by the addition of a 37-kDa glycopolypeptide. Incubation of intact caput, corpus and cauda spermatozoa with cauda epididymal fluid revealed major changes in the polypeptide maps of the incubation fluid and the membrane-enriched fractions of caput and corpus, but not cauda spermatozoa. The incubation of cauda fluid with caput and corpus sperm cells was characterized by a loss of several polypeptides and the addition of a 24-kDa glycopolypeptide. The most striking change in spermatozoa incubated with cauda epididymal fluid was the addition of two glycopolypeptides of 32 and 33 kDa to the polypeptide maps of caput sperm cells. These data demonstrate that rat spermatozoa undergo surface modifications during epididymal maturation and that these modifications can be influenced by epididymal fluid.     

有机阳离子转运子2在人类附睾中的表达及其意义

目的:研究人类附睾有机阳离子转运子2(OCTN2)mRNA的表达,探讨附睾肉碱转运机制,为探索男性避孕节育新技术提供理论依据。方法:应用RT-PCR方法检测人类附睾头、体、尾组织中OCTN2 mRNA的表达。结果:人类附睾头、体、尾组织中都存在OCTN2 mRNA表达。结论:人类附睾可能依赖OCTN2转运肉碱进入附睾管,为精子提供能量,促进精子成熟。对人类附睾OCTN2的进一步研究,将成为男性节育研究中新的分子靶标。     

Effect of piperine on the epididymis of adult male rats

Aim： To study the effect of piperine on the epididymal antioxidant system of adult male rats. Methods： Adult male rats were orally administered piperine at doses of 1 mg/kg, 10 mg/kg and 100 mg/kg body weight each day for 30 consecutive days. Twenty-four hours after the last treatment, the rats were weighed and killed with ether and the epididymis was dissected from the bodies. Sperm collected from the cauda region of the epididymis was used for the assessment of its count, motility and viability. Caput, corpus and cauda regions of the epididymis were separated and homogenized separately to obtain 10 % homogenates. The supernatants were used for the assays of sialic acid, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, lipid peroxidation and hydrogen peroxide generation. Results： Body weight of the piperine-treated rats remained unchanged. The weights of the caput, corpus and cauda regions of the epididymis significantly decreased at dose of 100 mg/kg. Epididymal sperm count and motility decreased at 10 mg/kg and 100 mg/kg, and sperm viability decreased significantly at 100 mg/kg. Sialic acid levels in the epididymis decreased significantly at 100 mg/kg while significant decrease in the cauda region alone was observed at 10 mg/kg. A significant decline in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, along with an increase in hydrogen peroxide generation and lipid peroxidation were observed at 10 mg/kg and 100 mg/kg. Conclusion： Piperine caused a decrease in the activity of antioxidant enzymes and sialic acid levels in the epididymis and thereby increased reactive oxygen species levels that could damage the epididymal environment and sperm function.     

Effect of gossypol on the concentration of sodium and potassium in the rat epididymis

The effects of administration of gossypol acetic acid (7.5 mg/kg daily for 4 weeks) on the concentration of Na+ and K+ in the rat epididymis was assessed. Epididymal fluid samples, collected by micropuncture, from the caput, corpus, proximal cauda and distal cauda epididymis from gossypol-treated and control animals were analysed for Na+ and K+ concentrations. Gossypol-treated males failed to impregnate healthy females, presumably because their sperm were immotile. In gossypol-treated rats, Na+ levels decreased significantly (P less than 0.01) in the caput, corpus, proximal and distal cauda epididymis. In contrast, the K+ concentration was increased significantly (P less than 0.05) only in the caput and corpus epididymis. This altered electrolyte milieu may be responsible, to some extent, for immotility and hence infertility.     

The appearance of basal cells in the developing murine epididymis and their temporal expression of macrophage antigens

This work demonstrates similarities between epididymal basal cells and macrophages in the mouse. Light microscopic studies of the postnatal development of the murine epididymis showed that basal cells were not present before days 12, 14 and 16 in the cauda, caput and corpus epididymis, respectively. An increase in cell number per unit length of tubule perimeter was demonstrated in all segments between days 20 and 27, when testicular fluid and spermatozoa start entering the epididymis. In the adult, there were more basal cells per unit perimeter in the cauda than caput or corpus epididymis. Conspicuous and consistent expression by basal cells of antigens detected by antibodies against tissue-fixed macrophages (F4/80) and mature macrophages (Mac-1) occurred only after they became established within the epithelium. Basal cells in the cauda epididymis did not display either antigen in the adult, although they persisted in the caput region. Such developmental patterns are compatible with the hypothesis that basal cells play a role in immune defence against sperm autoantigens.     

Effect of experimental varicocele on structure and function of epididymis in adolescent rats

Aim: To study the effect of experimental left varicocele (ELV) on epididymal structure and function in adolescent Sprague-Dawley rats. Methods: ELV was induced by partial ligation of the left renal vein. Sham-operated animals served as the controls. Four and 8 weeks after the operation, the histological, ultrastructural and biochemical (alpha-glucosidase activity and carnitine content) changes in different segments of the epididymis were observed. Results: In the treated animals, there were degeneration of the epididymal epithelium and edema of the interstitial tissue; numerous shedding cells, residual bodies, deformed sperm and macrophages appeared in the epididymal lumen. Morphometric measurement indicated a significant reduction in the epididymal tubular diameter (P<0.05) and a significant increase in the epididymal interstitial area (P<0.05) compared with the controls. Ultrastructural study showed sparse microvilli of the columnar epithelium, increased and enlarged lysosomes in the principal cells wi     

The presence of α-glucosidase, glycerophosphocholine and carnitine in the epididymis and ejaculate of the vervet monkey (Cercopithecus aethiops) and the Chacma baboon (Papio ursinus)

Summary.  The epididymis is the site of post-testicular sperm maturation in the male genital tract. Studies on human epididymides are hampered by the practical inaccessibility of epididymides of healthy men in their reproductive years. The limited use of laboratory animals therefore seems unavoidable. The objective was to establish baseline values of the epididymal markers α-glucosidase, glycerophosphocholine (GPC) and carnitine in the lumen of the caput, corpus and cauda epididymidis and in the ejaculate of adult male Chacma baboons and vervet monkeys. In both primates, α-glucosidase was found throughout the epididymis and in the ejaculate; values did not vary significantly. In monkeys, the highest concentration of GPC was found in the cauda epididymidis, but smaller amounts were found in the other regions and the ejaculate. In baboons, GPC was absent from the caput, but present in the other regions, including the ejaculate. Carnitine concentrations increased significantly from the caput to the cauda in monkeys and from the caput to the corpus in baboons. With this study, the relative concentration ranges in which these markers are present in the epididymides of these primates have been established. In future studies, changes in concentrations of these substances would probably indicate changes in epididymal function.     

Sperm maturation in dogs: sperm profile and enzymatic antioxidant status in ejaculated and epididymal spermatozoa

Spermatozoa become more susceptible to the attack of reactive oxygen species during maturation. To avoid oxidative damage, the epididymis must provide the necessary antioxidant protection. The aim of this study was to compare the canine sperm profile and the enzymatic antioxidant status of the ejaculated fractions and samples collected from the different segments of the epididymis (caput, corpus and cauda). Five adult dogs were used, and after 1–3 weeks, subsequently to bilateral orchiectomy and epididymal storage, sperm samples were collected from the different segments of the epididymis. Samples were evaluated for conventional microscopy and computer‐assisted motility analysis: sperm plasma membrane permeability and the activity of the antioxidant enzymes catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). Samples collected from the caput and corpus showed lower values for most of the motility variables evaluated, indicating different levels of immaturity. Catalase activity was observed only in ejaculated samples. Conversely, GPx activity was higher in the cauda epididymidis. Correlations were found between SOD and GPx and SOD and sperm motility in the epididymal cauda and corpus, highlighting the importance of the enzymes for the protection of spermatozoa during the transit along the epididymis.     

Age-dependent expression of the cystatin-related epididymal spermatogenic （Cres） gene in mouse testis and epididymis

Aim： To investigate the spatial and temporal expression of the cystatin-related epididymal spermatogenic （Cres） gene in mouse testis and epididymis during postnatal development. Methods： The QuantiGene assay and indirect immunofluorescence technique were used to examine the Cres mRNA and Cres protein level in mouse testis and epididymis on postnatal days 14, 20, 22, 28, 35, 49, 70 and 420. Results： （1） In both the testis and epididymis, Cres mRNA was fast detected on day 20, then it increased gradually from day 20 to day 70, and the high expression level maintained till day 420. （2） In the testis, the Cres protein was exclusively localized to the elongating spermatids and was first detected on day 22. The number of Cres-positive spermatids increased progressively till day 49. From day 49 to day 420, the number of Cres-positive cells was almost stable. （3） The Cres protein was first detected on day 20 in the proximal caput epididymal epithelium. By day 35, the expression level of the Cres protein increased dramatically and the high level was maintained till day 420. Moreover, the luminal fluid of the midcaput epididymis was also stained Cres-positive from day 35 on. No Cres-positive staining was observed in distal caput, corpus and cauda epididymis throughout. Conclusion： The Cres gene displays a specific age-dependent expression pattern in mouse testis and epididymis on both the mRNA and protein level.     

Autoradiographic Study of the [3H] Carnitine Distribution in Rat Epididymis

The distribution of [³H] carnitine in the epididymis has been studied by autoradiography 93 hours after injection of [³H]deoxycarnitine into intact, hemicastrated or hypophysectomized rats. In the intact animals, radioactivity is concentrated in the lumen of the caput and corpus with only a small amount observed in the caudal portion of the epididymis. In the hemicastrated rat, devoid of spermatozoa, the amount of radioactivity in the lumen of the caput and the cauda portions are lower than in the intact rats but still greater compared to the epididymal cells. In hypophysectomized rats the luminal labelling is much reduced. In contrast to the epididymis, the amount of radioactivity is low and evenly distributed in the heart from intact, hemicastrated and hypophysectomized rats and in the pituitary from intact and hemicastrated animals. The great reduction in luminal labelling after hypophysectomy emphasizes the hormonal dependence of the carnitine concentrating mechanism. These findings indicate that carnitine initially is concentrated in the caput and corpus portion of the epididymis. This intraluminal carnitine is subsequently transported into the caudal segment.
The evidence strongly supports the existence of a hormonal dependent carnitine concentrating mechanism localized on the luminal side of the epithelium in epididymis.