Sperm disposal system in spermatic granuloma: a link with superoxide radicals

Spermatic granulomas are believed to maintain "physiological harmony" in the male reproductive tract by maintaining a balance of hydrostatic pressure post-vasectomy. The mechanism for the disposal of deposited spermatozoa in the granuloma core is not clear. A fourfold rise in the production of superoxide along with ascorbyl and dienyl radicals and a 50% drop in the production of nitric oxide (NO) radicals by granuloma tissue hints that a reaction between NO and superoxide radicals could lead to the formation of peroxynitrite species which may contribute to the disposal of spermatozoa in the granuloma core. A higher protease activity and low hypoxanthine content in the granuloma indicates that a free radical driven sperm disposal system is active in granulomas.

Expression of CPI-17 and myosin phosphatase correlates with Ca(2+) sensitivity of protein kinase C-induced contraction in rabbit smooth muscle

1. Various smooth muscles have unique contractile characteristics, such as the degree of Ca(2+) sensitivity induced by physiological and pharmacological agents. Here we evaluated six different rabbit smooth muscle tissues for protein kinase C (PKC)-induced Ca(2+) sensitization. We also examined the expression levels of myosin light chain phosphatase (MLCP), the MLCP inhibitor phosphoprotein CPI-17, and the thin filament regulator h-calponin. 2. Immunohistochemical and Western blot analyses indicated that CPI-17 was found primarily in smooth muscle, although expression varied among different tissues. Vascular muscles contained more CPI-17 than visceral muscles, with further distinction existing between tonic and phasic subtypes. For example, the tonic femoral artery possessed approximately 8 times the cellular CPI-17 concentration of the phasic vas deferens. 3. In contrast to CPI-17 expression patterns, phasic muscles contained more MLCP myosin-targeting subunit than tonic tissues. Calponin expression was not statistically different. 4. Addition of phorbol ester to alpha-toxin-permeabilized smooth muscle caused an increase in contraction and phosphorylation of both CPI-17 and myosin light chain (MLC) at submaximal [Ca(2+)]i. These responses were several-fold greater in femoral artery as compared to vas deferens. 5. We conclude that the expression ratio of CPI-17 to MLCP correlates with the Ca(2+) sensitivities of contraction induced by a PKC activator. PKC stimulation of arterial smooth muscle with a high CPI-17 and low MLCP expression generated greater force and MLC phosphorylation than stimulation of visceral muscle with a relatively low CPI-17 and high MLCP content. This implicates CPI-17 inhibition of MLCP as an important component in modulating vascular muscle tone.

Distribution of the vacuolar H+ atpase along the rat and human male reproductive tract

Luminal acidification in parts of the male reproductive tract generates an appropriate pH environment in which spermatozoa mature and are stored. The cellular mechanisms of proton (H+) secretion in the epididymis and the proximal vas deferens involve the activity of an apical vacuolar H+ ATPase in specialized cell types, as well as an apical Na+/H+ exchanger in some tubule segments. In this study we used Western blotting and immunocytochemistry to localize the H+ ATPase in various segments of the male reproductive tract in rat and man as a first step toward a more complete understanding of luminal acidification processes in this complex system of tissues. Immunoblotting of isolated total cell membranes indicated a variable amount of H+ ATPase in various segments of the rat reproductive tract. In addition to its known expression in distinct cell types in the epididymis and vas deferens, the H+ ATPase was also localized at the apical pole and in the cytoplasm of epithelial cells in the efferent duct (nonciliated cells), the ampulla of the vas deferens and the ventral prostate (scattered individual cells), the dorsal and lateral prostate, the ampullary gland, the coagulating gland, and all epithelial cells of the prostatic and penile urethra. Both apical and basolateral localization of the protein were found in epithelial cells of the prostatic ducts in the lateral prostate and in periurethral tissue. Only cytoplasmic, mostly perinuclear localization of the H+ ATPase was found in all epithelial cells of the seminal vesicles and in most cells of the ventral prostate and coagulating gland. No staining was detected in the seminiferous tubules, rete testis, and bulbourethral gland. In human tissue, H+ ATPase-rich cells were detected in the epididymis, prostate, and prostatic urethra. We conclude that the vacuolar H+ ATPase is highly expressed in epithelial cells of most segments of the male reproductive tract in rat and man, where it may be involved in H+ secretion and/or intracellular processing of the material endocytosed from the luminal fluid or destined to be secreted by exocytosis.

Expression of the transmembrane carbonic anhydrases, CA IX and CA XII, in the human male excurrent ducts

Testicular fluid is concentrated and acidified during its passage through the excurrent ducts. These processes involve bicarbonate absorption, in which carbonic anhydrases are implicated. In this study, the distribution of two transmembrane carbonic anhydrase isozymes (CA IX and CA XII) in the human excurrent ducts was investigated using isozyme-specific antibodies in conjunction with immunohistochemical and immunoblotting techniques. Specific staining for CA XII was present in the basolateral plasma membrane of the epithelial cells in the efferent ducts, predominantly in the non-ciliated cells. In the epididymal duct, CA XII was detected only in sporadic cells, which also contained CA II, thus suggesting that they are apical mitochondria-rich cells. CA IX was also localized to the basolateral plasma membrane of the epithelium in the efferent ducts, but its staining was weaker and less uniform compared to CA XII. No signal for CA IX was detected in the epididymal duct. Western blot analysis from efferent duct samples revealed specific bands for CA IX and CA XII, confirming that the immunohistochemical stainings represent these isozymes. The expression of CA XII and CA IX in the excurrent duct system and co-expression of CA XII with Aquaporin-1 in the same efferent duct epithelial cells suggest their functional involvement in ion transport and concentration processes of testicular fluid.

The cellular physiology of carbonic anhydrases

Carbonic anhydrases are zinc metalloenzymes that catalyze the reversible hydration of CO(2) to form HCO(3)(-) and protons according to the following reaction: CO(2) + H(2)O <=> H(2)CO(3) <=> HCO(3)(-) + H(+). The first reaction is catalyzed by carbonic anhydrase and the second reaction occurs instantaneously. The carbonic anhydrase (CA) gene family includes ten enzymatically active members, which are major players in many physiological processes, including renal and male reproductive tract acidification, bone resorption, respiration, gluconeogenesis, signal transduction, and formation of gastric acid. The newly identified CA IX (previously called MN) and CA XII are related to cell proliferation and oncogenesis. Carbonic anhydrase isozymes have different kinetic properties and they are present in various tissues and in various cell compartments. CA I, II, III and VII are cytoplasmic, CA V is mitochondrial, and CA VI is present in salivary secretions. CA IV, IX, XII and XIV are membrane proteins: CA IV is a glycosyl-phosphatidylinositol-anchored protein, and CA IX, XII and XIV are transmembrane proteins. The present work will focus on the roles of CA II and CA IV in transepithelial proton secretion and bicarbonate reabsorption processes. The localization of these isoforms in selected epithelia that are involved in net acid/base transport, such as kidney proximal tubules and collecting ducts, and tubules from the male reproductive tract will be reviewed.

Constant expression of cyclooxygenase-2 gene in prostate and the lower urinary tract of estrogen-treated male rats

Expression of cyclooxygenase-2 (E. C. 1.14.99.1) in prostate and the lower urinary tract (LUT) of the neonatally estrogenized male rat has been studied by using a COX-2's PCR fragment of 724 nt spanning 3 introns and a 478nt internal standard for quantitative RT-PCR. The same fragment of 724 nt was used for RNA probe in Northern hybridization. Neonatal estrogenization (10 microg/day of diethylstilbestrol on days 1-5) had no effect on COX-2 expression in prostatic urethra, prostatic lobes, or bladder. Acute estrogen treatment of castrated animals did not induce COX-2 expression, either. In addition the differential expression of basal level of COX-2 in the different lobes of prostate in normal rat was demonstrated. Our results suggest a constant expression of COX-2 gene in prostate and the lower urinary tract of the neonatally estrogenized (neoDES) rats. The present study indicates that the increased expression of COX-2 is probably not essential for the estrogen-driven development of stromal inflammation or hyperplastic and dysplastic alterations in the prostate of neoDES rats.

Expression and regulation of H+K+ATPase in lysosomes of epithelial cells of the adult rat epididymis

Endocytosis is an important event in the epididymis as it contributes to a luminal environment conducive for sperm maturation. Principal and clear cells contain numerous lysosomes which degrade many substances internalized by endocytosis from the epididymal lumen. The interior of the lysosomes depends on low pH to activate the release of their enzymes and to activate their acid hydrolases. In the present study, H+K+ATPase was localized by light microscopy in the adult rat epididymis of intact and of orchidectomized animals supplemented with testosterone or not. In normal animals, numerous lysosomes of nonciliated cells of the efferent ducts were intensely reactive for anti-H+K+ATPase antibody. In the initial segment, only a few lysosomes of principal cells were reactive. In the intermediate zone of the epididymis, numerous lysosomes of principal cells were intensely reactive, while the number of intensely reactive lysosomes decreased progressively from the proximal caput to the distal caput with none being seen in the proximal corpus region. In the distal corpus and cauda regions, only a few lysosomes of some principal cells were reactive. In contrast, clear cells of all regions showed intense reactivity. Orchidectomy resulted in the abolishion of H+K+ATPase in lysosomes of principal cells of all regions except the initial segment. However, while clear cells of the caput and corpus regions also became unreactive, those of the cauda region remained as reactive as in controls. Orchidectomized animals supplemented with testosterone maintained a staining pattern similar to controls for both cell types. These observations demonstrate the presence in principal and clear cells of H+K+ ATPase which may have an important role in acidifying the interior of their lysosomes. However, there is a region-specific expression of H+K+ATPase in lysosomes of principal cells, unlike that for clear cells. In addition, H+K+ATPase expression in lysosomes of principal cells depends on testosterone in all regions except the initial segment. However, in the case of clear cells, only those of the caput and the corpus regions are dependent on testosterone, while those of the cauda region appear to be regulated by some other factor.

Physiological functions and hormonal regulation of mouse vas deferens protein (AKR1B7) in steroidogenic tissues

The MVDP (mouse vas deferens protein) gene encodes an aldose reductase-like protein (AKR1B7) highly expressed in vas deferens epithelium and zona fasciculata of the adrenal cortex. Recombinant MVDP showed kinetic properties distinct from those of aldose reductase, including its spectrum of substrates, cofactor preference and sensitivity to inhibitors. We demonstrate that in adrenocortical cells, MVDP, rather than aldose reductase, is the principal reductase for isocaproaldehyde (a product of side-chain cleavage of cholesterol) and 4-hydroxynonenal (a lipid peroxidation product). In steroidogenic tissues MVDP expression is regulated by pituitary trophic hormones, namely ACTH in adrenals, FSH in ovaries, and LH in testicular Leydig cells.

Correlation between the release of the sympathetic neurotransmitter ATP and soluble nucleotidases from the guinea pig vas deferens

Recently, we have shown that by releasing specific nucleotidases the sympathetic nerves of the guinea pig vas deferens may regulate the metabolism of extracellular adenine nucleotides and consequently, the inactivation of neurotransmitter ATP. Based on the evidence for tetrodotoxin sensitivity and calcium dependence of the nerve stimulation-evoked overflow of enzyme activity, we have suggested that soluble nucleotidases may be stored in synaptic vesicles within the sympathetic nerves and released upon arrival of nerve action potentials by a mechanism similar to that for release of neurotransmitters. To further test this hypothesis we studied the time course of nerve stimulation-evoked overflow of ATP, norepinephrine (NE), releasable ATPase (r-ATPase) activity, and releasable AMPase (r-AMPase) activity under control conditions and in the presence of drugs known to selectively modulate sympathetic neurotransmission. The results show that the time course of overflow of r-ATPase and r-AMPase activities resembles the transient pattern of overflow of ATP but not the tonic pattern of overflow of NE. Vasa deferentia dissected from animals treated with reserpine release ATP, r-ATPase, and r-AMPase, whereas the overflow of NE is completely abolished. Guanethidine, on the other hand, inhibits equally well the overflow of the two neurotransmitters and the releasable nucleotidase activities. Agonists of the alpha(2)-adrenergic receptors abolish the overflow of ATP, r- ATPase, and r-AMPase but not the overflow of NE. This evidence supports the idea that the sympathetic nerves of the guinea pig vas deferens store and release ATP together with specific nucleotidases responsible for the inactivation of this neurotransmitter.

Expression of the lipocalin-type prostaglandin D synthase gene in the reproductive tracts of Holstein bulls

The aim of this study was to localize expression of the prostaglandin D synthase gene in the reproductive tracts of Holstein bulls using northern blotting and in situ hybridization. For northern blotting, a digoxigenin-labelled prostaglandin D synthase cDNA probe was used to probe blots containing RNA isolated from the testes, epididymides, vas deferens, ampullae, seminal vesicles, prostate and bulbourethral glands of bulls. The digoxigenin-labelled cDNA for the bovine homologue of prostaglandin D synthase hybridized to a single band (approximately 0.9 kb) to RNA samples from the caput, corpus and cauda epididymides, as well as RNA samples from the vas deferens and the ampulla. The probe also detected a single band in testis samples, although the transcript size was slightly larger (approximately 1.0 kb) than the transcript found in the other tissues. The highest expression of prostaglandin D synthase was observed in the testes and caput epididymides. Prostaglandin D synthase transcripts were not found in the seminal vesicles or the prostate or bulbourethral glands using northern blotting. For in situ hybridization, antisense and sense riboprobes were synthesized and used to hybridize to cryosections obtained from the reproductive tissues of bulls. In situ hybridization of bull testes showed that prostaglandin D synthase transcripts were present within the germ cells in the adluminal compartment of the seminiferous tubules containing round and elongated spermatids, indicating that expression varied with stage of development of the seminiferous tubules. Prostaglandin D synthase expression was observed in the epithelial cells of the epididymides with greatest expression occurring in the caput epididymidis. Some expression was also observed in the epithelial cells of the vas deferens and a few cells of some lobules in the prostate and bulbourethral glands. Expression of the prostaglandin D synthase gene was not detected in ampullae or seminal vesicles by in situ hybridization.

Release of a soluble ATPase from the rabbit isolated vas deferens during nerve stimulation

The properties of the ATPase released during electrical field stimulation (EFS) (8 Hz, 25 s) of the sympathetic nerves of the superfused rabbit isolated vas deferens were investigated. Superfusate collected during EFS rapidly metabolised exogenous ATP (100 microM) and 50% was broken down in 5.67+/-0.65 min. The main metabolite was ADP, virtually no AMP was produced and adenosine was absent. No enzyme activity was seen in samples collected in the absence of EFS. Lineweaver-Burke analysis of the initial rates of ATP hydrolysis gave a K(M) of 40 microM and V(max) of 20.3 nmol ATP metabolized min(-1) ml(-1) superfusate. ATPase activity was unaffected by storage at room temperature for 24 h, but was abolished at pH4 or by heating at 80 degrees C for 10 min. ARL 67156 inhibited ATP breakdown in a concentration-dependent manner (IC(50)=25 microM (95% confidence limits=22-27 microM), Hill slope=-1.06+/-0.04). When EFS was applied three times at 30 min intervals, ATP metabolism was 20-30% less in superfusate collected during the second and third stimulation periods compared with the first. ATPase activity was released in a frequency-dependent manner, with significantly greater activity seen after stimulation at 4 and 8 Hz than at 2 Hz. In conclusion, EFS of the sympathetic nerves in the rabbit vas deferens causes release of substantial ATPase, but little ADPase activity into the extracellular space. This contrasts with the guinea-pig vas deferens, which releases enzymes that degrade ATP to adenosine. Thus, the complement of enzymes released by nerve stimulation is species-dependent.

Down-regulation of Na(+)/K(+)-ATPase alpha(2) isoform in denervated rat vas deferens

In the rat vas deferens, an organ richly innervated by peripheral sympathetic neurons, we have demonstrated recently the expression of alpha(1) and alpha(2), but not alpha(3) isoforms of the alpha subunit of Na(+)/K(+)-ATPase (EC 3.6.1.37), a membrane-bound enzyme of vital function for living cells (Noël et al., Biochem Pharmacol 55: 1531-1535, 1998). In the present work, we characterized, qualitatively and quantitatively, Na(+)/K(+)-ATPase alpha isoforms in denervated rat vasa deferentia. [(3)H]Ouabain binding at concentrations defined for high-affinity isoforms (alpha(2) and/or alpha(3)) detected only one class of specific binding sites in control (C) and denervated (D) vas deferens. Although the dissociation constant was similar for both groups [K(d) = 138 +/- 14 nM (C) and 125 +/- 8 nM (D)], a marked decrease in density was observed after denervation [716 +/- 81 fmol.mg protein(-1) (C) and 445 +/- 34 fmol.mg protein(-1) (D), P < 0.05]. In addition, western blotting revealed that denervated vasa deferentia produce the alpha(1) and alpha(2) isoforms but not alpha(3), just as we reported for the controls previously (Noël et al., Biochem Pharmacol 55: 1531-1535, 1998). Densitometric analysis showed a decrease of the alpha(2) isoform by about 40% in denervated organs, in very good agreement with what was shown with the [(3)H]ouabain binding technique, but no significant change in alpha(1) isoform density. Truncated alpha(1) (alpha(1)T), an isoform suggested to exist in the guinea pig vas deferens, was not detected. Altogether, our results demonstrated that Na(+)/K(+)-ATPase alpha(2) is down-regulated after sympathetic denervation of the rat vas deferens.

Characterization of the ATPase released during sympathetic nerve stimulation of the guinea-pig isolated vas deferens

The release of ATPase activity evoked by electrical field stimulation (EFS) (8 Hz, 25 s) was investigated in several tissues in which adenosine 5'-triphosphate (ATP) acts as a neurotransmitter. Superfusate collected during EFS of sympathetic nerves of the guinea-pig, rat and mouse isolated vas deferens and parasympathetic nerves of the guinea-pig isolated urinary bladder contained ATPase activity. ATP breakdown was fastest in superfusate collected from the guinea-pig isolated vas deferens. However, EFS of the enteric nerves of the guinea-pig isolated taenia coli did not release any detectable ATPase. The ATPase released from the guinea-pig isolated vas deferens metabolized ATP at similar rates at incubation temperatures of 37 degrees C and 20 degrees C. Lineweaver-Burke analysis of the initial rates of ATP hydrolysis gave a K(M) of 39 microM and a V(max) of 1039 pmol ATP metabolized min(-1) ml(-1) superfusate. 6-N,N-diethyl-D-beta,gamma-dibromomethyleneATP (ARL 67156), pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) and pyridoxal-5'-phosphate (P-5-P) all inhibited the ATPase activity in a concentration-dependent manner with a potency order of ARL 67156 = PPADS>P-5-P. In conclusion, EFS of several tissues in which ATP is a neurotransmitter causes the release of an ATPase and activity is greatest in the guinea-pig vas deferens. The enzyme has pharmacological and kinetic characteristics that are similar to ectonucleoside triphosphate diphosphohydrolases.

H(+)V-ATPase-dependent luminal acidification in the kidney collecting duct and the epididymis/vas deferens: vesicle recycling and transcytotic pathways

Many vertebrate transporting epithelia contain characteristic ‘mitochondria-rich’ cells that express high levels of a vacuolar proton-pumping ATPase (H(+)V-ATPase) on their plasma membrane and on intracellular vesicles. In the kidney cortex, A-cells and B-cells are involved in proton secretion and bicarbonate secretion, respectively, in the distal nephron and collecting duct. A-cells have an H(+)V-ATPase on their apical plasma membrane and on intracellular vesicles, whereas the cellular location of the H(+)V-ATPase can be apical, basolateral, bipolar or diffuse in B-cells. The rat epididymis and vas deferens also contain a distinct population of H(+)V-ATPase-rich epithelial cells. These cells are involved in generating a low luminal pH, which is involved in sperm maturation and in maintaining sperm in an immotile state during their passage through the epididymis and vas deferens. In both kidney and reproductive tract, H(+)V-ATPase-rich cells have a high rate of apical membrane recycling. H(+)V-ATPase molecules are transported between the cell surface and the cytoplasm in vesicles that have a well-defined ‘coat’ structure formed of the peripheral V(1) subunits of the H(+)V-ATPase. In addition, we propose that B-type intercalated cells have a transcytotic pathway that enables them to shuttle H(+)V-ATPase molecules from apical to basolateral plasma membrane domains. This hypothesis is supported by data showing that A-cells and B-cells have different intracellular trafficking pathways for LGP120, a lysosomal glycoprotein. LGP120 was found both on the basolateral plasma membrane and in lysosomes in B-cells, whereas no LGP120 was detectable in the plasma membrane of A-cells. We propose that the ‘polarity reversal’ of the H(+)V-ATPase in B-intercalated cells is mediated by a physiologically regulated transcytotic pathway that may be similar to that existing in some other cell types.

Comparative localization of heme oxygenase-2 and nitric oxide synthase in the autonomic innervation to the human ductus deferens and seminal vesicle

PURPOSE

The aim of present study was to determine the topographic relationship between heme oxygenase-2 (HO-2), which synthesizes carbon monoxide (CO), and neuronal nitric oxide synthase (nNOS), which generates nitric oxide (NO), in the autonomic nerves of the human ductus deferens and seminal vesicle.

MATERIALS AND METHODS

Specimens of the ductus deferens and seminal vesicle were obtained during cancer surgery or vasectomy. HO-2 and nNOS were localized by indirect immunofluorescence. Additionally, the histochemical NADPH-diaphorase (NADPH-d) activity of NOS was demonstrated using a standard staining method and some modifications.

RESULTS

Anti-HO-2 labeling stained virtually all nerve cell bodies in local ganglia of the pelvic plexus, which is composed of a mixed population of postganglionic sympathetic and parasympathetic neurons supplying the pelvic viscera. Furthermore, nerve cell bodies in the wall of the seminal vesicle, which are considered an extension of the pelvic plexus, were also found to stain positively for HO-2. Some of the HO-2-immunoreactive ganglion cells were also nNOS-positive, their proportion varying between individual ganglia but generally not exceeding 20%. Both enzymes were present in large adventitial nerve trunks. Only nNOS but no HO-2 was found in small intramuscular and mucosal nerve fibers. In both the ductus deferens and seminal vesicle, the highest density of nNOS-containing nerve fibers was in the lamina propria of the mucosa. A well-developed plexus of nNOS-positive nerve fibers was also observed in the muscular layer of the seminal vesicle. By contrast, there was a very sparse innervation by nNOS-positive nerve fibers in the muscle coat of the ductus deferens. In addition, a population of epithelial cells in the seminal vesicle may contain an isoform of NOS, as revealed by a resistant NADPH-d activity.

CONCLUSIONS

These findings set the scene for functional studies which will hopefully clarify the biological role of CO and NO in the control of the ductus deferens and seminal vesicle.

Product of side-chain cleavage of cholesterol, isocaproaldehyde, is an endogenous specific substrate of mouse vas deferens protein, an aldose reductase-like protein in adrenocortical cells

Mouse vas deferens protein (MVDP) is an aldose reductase-like protein that is highly expressed in the vas deferens and adrenal glands and whose physiological functions were unknown. We hereby describe the enzymatic characteristics of MVDP and its role in murine adrenocortical Y1 cells. The murine aldose reductase (AR) and MVDP cDNAs were expressed in bacteria to obtain recombinant proteins and to compare their enzymatic activities. Recombinant MVDP was functional and displayed kinetic properties distinct from those of murine AR toward various substrates, a preference for NADH, and insensitivity to AR inhibitors. For MVDP, isocaproaldehyde, a product of side-chain cleavage of cholesterol generated during steroidogenesis, is the best natural substrate identified so far. In Y1 cells, we found that NADH-linked isocaproaldehyde reductase (ICR) activity was much higher than NADPH-linked ICR activity and was not abolished by AR inhibitors. We demonstrate that in Y1 cells, forskolin-induced MVDP expression enhanced NADH-linked ICR activity by 5-6-fold, whereas no variation in ICR-linked NADPH activity was observed in the same experiment. In cells stably transfected with MVDP antisense cDNA, NADH-linked ICR activity was abolished even in the presence of forskolin, and the isocaproaldehyde toxicity was increased compared with that of intact Y1 cells, as measured by isocaproaldehyde LD(50). In Y1 cells transfected with MVDP antisense cDNA, forskolin-induced toxicity was abolished by aminoglutethimide. These results indicate that in adrenocortical cells, MVDP is responsible for detoxifying isocaproaldehyde generated by steroidogenesis.

Immunocytochemical localization of the Ya, Yb1, Yc, Yf, and Yo subunits of glutathione S-transferases in the cauda epididymidis and vas deferens of adult rats

Glutathione S-transferases (GSTs) are dimeric proteins grouped into five classes based on the degree of amino acid homology of their subunits. They are involved in cellular detoxification through the catalyzation of the conjugation of reduced glutathione with various electrophilic substances. In the present study, the distribution of Ya and Yc subunits from the alpha family, Yb1 and Yo subunits of the mu class, and the Yf subunit of the pi class were examined with light microscope immunocytochemistry in Bouin-fixed, paraffin-embedded tissue of different regions of the cauda epididymidis and vas deferens. In the cauda, principal cells showed high levels of expression of Ya, Yc, and Yo subunits, while in the vas deferens, staining decreased to moderate levels for the Ya and Yo subunits and to low levels for the Yc subunit. While Yf was maintained at low levels in principal cells of all cauda and vas deferens regions, Yb1 expression was more erratic, presenting a checkerboard-like staining pattern in the proximal vas deferens and showing moderate cytoplasmic but intense nuclear reactivity in all other regions. Basal cells in the cauda were intensely reactive for Yf, while in the vas deferens, they became unreactive. Conversely, basal cells were unreactive for Ya in the cauda and proximal vas deferens, while in the middle and distal vas deferens, they became moderately reactive. In the case of Yb1 and Yo, some basal cells were reactive while others appeared unreactive in all cauda and vas deferens regions. Yc elicited the display of both reactive and unreactive basal cells in the cauda regions, and while the cells were moderately reactive in the proximal vas deferens, they became intensely reactive in the middle and distal vas deferens. In summary, both principal and basal cells show varying degrees of GST expression in the different regions of the cauda and vas deferens, suggesting that these cells are subjected to a complex, changing environment of substrates. Furthermore, while expression often differs from principal to basal cells, the absence of reactivity of a given GST in one cell type is usually compensated for by expression in the other cell type in any given region of the cauda or vas deferens. Taken together, the data suggest that ample protection from harmful circulating electrophiles can be provided for sperm during their storage in the cauda and vas deferens. In addition, since principal cells of the vas deferens are involved in steroid synthesis, the presence of GSTs in these cells may also serve to bind steroids, or this presence may be involved in steroid isomerization.

Exogenous 17beta-estradiol blocks alpha and mu but not pi class glutathione S-transferase immunoreactivity in epithelium of Syrian hamster vas deferens

Members of the glutathione S-transferase (GST) family of detoxification enzymes play a role in chemotherapy resistance in certain cancers but have not been directly implicated as agents whose absence may predispose tissues to hormonally induced tumorigenesis. Here we report the development of a polyclonal antiserum to a hamster mu class GST, and immunohistochemical analysis of alpha, mu, and pi class GSTs to study the effects of hormone treatment on their expression in reproductive tract tissues of male golden Syrian hamsters. These animals develop leiomyosarcomas in the vas deferens after treatment with testosterone propionate (TP) and 17beta-estradiol (E2). High levels of all three GST classes were detected throughout the reproductive tract epithelium of control animals. In 100% of the experimental animals, 4 weeks of treatment either with E2 alone, or with E2 plus TP promoted a complete loss of immunostaining for alpha and mu class GSTs, but not for pi class GSTs, only in the epithelial lining of the vas deferens. In contrast, treatment with TP alone resulted in moderate hyperplasia of smooth muscle in the proximal vas deferens, with no cellular atypia and no changes in immunoreactivity of any of the GST classes. The consistent and site-specific nature of these results strongly suggests a functional role for GSTs in hormonally induced carcinogenic process. (J Histochem Cytochem 47:91-98, 1999)

Principal cells of the vas deferens are involved in water transport and steroid synthesis in the adult rat

Principal cells show marked structural differences in the proximal, middle, and distal regions of the vas deferens, reflective of diverse functional activities. In the present study, we performed electron microscopy to examine the structural features of principal cells using glutaraldehyde-fixed, Epon-embedded material, while functional parameters were examined using light microscopic immunocytochemistry on Bouin-fixed, paraffin-embedded material. In the proximal region, the cuboidal principal cells resembled those of the cauda epididymidis, but few clear cells and occasional narrow cells were present. In the middle region, principal cells often contained blebs of their apical cytoplasm containing vesicular and tubular profiles. These blebs extended far from the cell surface and appeared to be liberated into the lumen, suggesting an apocrine type of secretion. In the distal region, dilated intercellular spaces containing numerous membranous profiles of different shapes and sizes were noted between adjacent principal cells and overlying basal cells. The use of an anti-aquaporin-1 antibody revealed an intense reaction over the endothelial cells of numerous vascular channels in the lamina propria. Taken together, these observations suggested water transport from the lumen of the vas deferens via the dilated spaces to underlying vascular channels, the function of which may be to concentrate sperm. The infranuclear cytoplasm of principal cells of this region showed whorls of smooth endoplasmic reticulum (sER). Large intracytoplasmic cavities were found within the sER aggregates, and these contained membranous profiles that appeared to peel off from the surrounding sER elements. Various images of such cavities closely juxtaposed to the lateral plasma membrane suggested that the membranous profiles of the intercellular spaces were derived from them. Use of anti-3beta-hydroxysteroid dehydrogenase antibody revealed an intense reaction over principal cells of the vas deferens, as well as over the blebs in the lumen of the vas deferens, which is indicative of the steroid synthesis performed by these cells. The release of sER membranous profiles into the dilated spaces and the presence of blebs in the lumen may represent a means of transporting steroids that are destined for different sites out of the principal cells. Steroids in the blebs would be ultimately destined for utilization by luminal sperm, while those steroids in the dilated spaces are designed for utilization by muscle layers of the lamina propria. In summary, principal cells of the vas deferens appear to be involved in synthesis and secretion of steroids and in eliminating water from the lumen of the vas deferens.

GPx3: the plasma-type glutathione peroxidase is expressed under androgenic control in the mouse epididymis and vas deferens

We report here-using northern experiments, western blotting, and immunohistochemistry-on the findings that the plasma type glutathione peroxidase, GPx3, a major enzyme in reducing lipid hydroperoxides and hydrogen peroxide in plasma, is also expressed at significant levels in tissues of the male genital tract including epididymis and vas deferens. Within the epididymis and the kidney, the accumulation of the GPx3 mRNA and protein were investigated during postnatal development and found to be temporally regulated in a tissue-specific manner. Furthermore, we show here that androgen withdrawal by castration down regulates the expression of the GPx3 gene both in the epididymis and vas deferens while GPx3 expression in the kidney was found to be androgen-independent. Finally, immunohistochemistry data reveals that within the epididymis GPx3 distribution is quite peculiar suggesting the existence in this organ of complex traductional and/or transcriptional regulatory processes.

NADPH-diaphorase in glandular cells and nerves and its relation to acetylcholinesterase-positive nerves in the male reproductive tract of man and guinea-pig

The presence of NADPH-diaphorase activity and acetylcholinesterase in the testis, epididymis, vas deferens, seminal vesicle, pelvic plexus, prostate and urethra of man and guinea-pig was investigated with the nitro blue NADPH technique and the thiocholine method, respectively. In human material NADPH-diaphorase activity was found in the Leydig cells, Sertoli cells and the epithelial linings of the rete testis, the excretory ducts, seminal vesicle, prostate and urethra. The guinea-pig material showed staining of the Leydig cells and spermatozoa and similar epithelial staining of the tract as man. Nerves beneath the epithelium and in the muscle layers of cauda epididymis, vas deferens, seminal vesicle, prostate and urethra were also stained. NADPH-diaphorase-positive nerve cells were seen in the pelvic plexus. Some cells also displayed acetylcholinesterase activity but others showed activity for only one of the enzymes or no activity for either enzyme. In the cauda epididymis, vas deferens, seminal vesicle, prostate and urethra acetylcholinesterase-positive nerve fibres formed a plexus beneath the secretory cells. It is concluded that NADPH-diaphorase, generally accepted as a nitric oxide synthase, is present in glandular cells of the male genital tract. The enzyme is also present in nerves, where it is partly co-localized with acetylcholinesterase.

Constitutive expression of cyclooxygenase-2 in rat vas deferens

Prostaglandins, lipoid substances discovered in human semen as modulators of uterine muscle contractility, are known to play significant roles in virtually all mammalian organ systems, but their male reproductive functions are unclear. Cyclooxygenase, the rate-limiting enzyme in prostaglandin synthesis, occurs in two isoforms distinguished on the basis of constitutive (COX-1) or inducible (COX-2) expression patterns in mammalian tissues. However, in the adult rat male reproductive system, immunohistochemistry and Western and Northern analysis showed that COX-2 is the predominant isoform and is heavily localized to the epithelium of the distal vas deferens, where constitutive expression is manyfold greater than in any other organs of the body. COX-2 is not detected in the proximal one-half of the vas nor in the testis, epididymis, seminal vesicles, or prostate. Elimination of luminal sperm by vasectomy does not affect COX-2 levels, whereas castration severely depletes COX-2 and androgen replacement after castration restores COX-2, indicating that COX-2 expression in the vas is androgen dependent. Because the distal vas also comprises an extensive submucosal venous plexus connected to the penile corpora cavernosa, prostaglandins from the vas may play a role in erection.

Creatine synthesis and transport systems in the male rat reproductive tract

Previous studies from this laboratory showed that high levels of guanidinoacetate methyltransferase are present in mouse testis and epididymis, whereas guanidinoacetate methyltransferase mRNA and protein are not detected in seminal vesicles where large amounts of creatine (Cr) and phosphocreatine are found (Lee et al., Biol Reprod 1994; 50:152-162). To further investigate the origin(s) of Cr in the male reproductive tract, the expression patterns of the three enzymes and a transporter involved in Cr metabolism were examined with rat reproductive tissues. Western blot analysis showed that expression of L-arginine:glycine amidinotransferase was limited to the kidney. On the other hand, high levels of the mRNAs for both guanidinoacetate methyltransferase and Sadenosylhomocysteine hydrolase were expressed in the testis and epididymis as well as the liver and kidney. Cr transporter mRNA was highly expressed in the seminal vesicle and vas deferens. These results suggest that the source of Cr in the male reproductive tract varies depending on the tissue; in the testes and epididymides, Cr is synthesized from guanidinoacetate, while in the seminal vesicles, Cr is transported from blood. Previous and present findings suggest the importance of Cr metabolism and/or transport for reproductive functions.

Quantitative analysis of the high-affinity binding sites for [3H]ouabain in the rat vas deferens and their immunological identification as the alpha 2 isoform of Na+/K(+)-ATPase

Binding assays were performed with [3H]ouabain to investigate the presence of, and to characterize, a Na+/K(+)-ATPase isoform with high affinity for cardiac glycosides in the rat vas deferens. Nonlinear regression analysis of equilibrium experiments carried out with crude preparations in a Mg-Pi medium indicated the presence of high-affinity sites characterized with good precision (individual coefficients of variation = 11-35%) by their density (Bmax = 0.42 to 0.72 pmol/mg protein) and dissociation constant (Kd = 0.069 to 0.136 microM) values. The values of the dissociation rate constant (kappa-1) and the association rate constant (kappa+1) for these sites were 0.151 to 0.267 min-1 and 2.87 to 3.60 microM-1.min-1, respectively. A higher number of low-affinity sites (Kd around 15 microM), supposed to correspond to the alpha 1 isoform, was also identified, but their Kd and Bmax values were not quantified precisely in this crude preparation. Western blot assays indicated hybridization with specific anti-alpha 1 and anti-alpha 2 isoform antibodies but not with anti-alpha 3 isoform antibody. Taken together, the present results indicate the existence of a low proportion of the alpha 2 isoform of Na+/K(+)-ATPase in the rat vas deferens that can be quantified precisely by [3H]ouabain binding even in a crude membrane preparation that is suitable for studies under conditions of plasticity.