Morphology and immunolocalization of aquaporins 1 and 9 in the agouti (Dasyprocta azarae) testis excurrent ducts

This study investigated the morphology and immunoexpression of aquaporins (AQPs) 1 and 9 in the rete testis, efferent ducts, epididymis, and vas deferens in the Azara’s agouti (Dasyprocta azarae). For this purpose, ten adult sexually mature animals were used in histologic and immunohistochemical analyses. The Azara’s agouti rete testis was labyrinthine and lined with simple cubic epithelium. Ciliated and non-ciliated cells were observed in the epithelium of the efferent ducts. The epididymal cellular population was composed of principal, basal, apical, clear, narrow, and halo cells. The epithelium lining of vas deferens was composed of the principal and basal cells. AQPs 1 and 9 were not expressed in the rete testis. Positive reaction to AQP1 was observed at the luminal border of non-ciliated cells of the efferent ducts, and in the peritubular stroma and blood vessels in the epididymis, and vas deferens. AQP9 was immunolocalized in the epithelial cells in the efferent ducts, epididymis and vas deferens. The morphology of Azara’s agouti testis excurrent ducts is similar to that reported for other rodents such as Cuniculus paca. The immunolocalization results of the AQPs suggest that the expression of AQPs is species-specific due to differences in localization and expression when compared to studies in other mammals species. The knowledge about the expression of AQPs in Azara’s agouti testis excurrent ducts is essential to support future reproductive studies on this animal, since previous studies show that AQPs may be biomarkers of male fertility and infertility.     

Differential expression of estrogen receptors alpha and beta in the reproductive tracts of adult male dogs and cats

Expression of estrogen receptors (ERs) in the reproductive tracts of adult male dogs and cats has not been reported. In the present study, ERalpha and ERbeta were localized by immunohistochemistry using ER-specific antibodies. ERalpha was found in interstitial cells and peritubular myoid cells in the dog testis, but only in interstitial cells of the cat. In rete testis of the dog, epithelial cells were positive for ERalpha staining, but in the cat, rete testis epithelium was only weakly positive. In efferent ductules of the dog, both ciliated and nonciliated cells stained intensely positive. In the cat, ciliated epithelial cells were less stained than nonciliated epithelial cells. Epithelial cells in dog epididymis and vas deferens were negative for ERalpha. In the cat, except for the initial region of caput epididymis, ERalpha staining was positive in the epithelial cells of epididymis and vas deferens. Multiple cell types of dog and cat testes stained positive for ERbeta. In rete testis and efferent ductules, epithelial cells were weakly positive for ERbeta. Most epithelial cells of the epididymis and vas deferens exhibited a strong positive staining in both species. In addition, double staining was used to demonstrate colocalization of both ERalpha and ERbeta in efferent ductules of both species. The specificity of antibodies was demonstrated by Western blot analysis. This study reveals a differential localization of ERalpha and ERbeta in male dog and cat reproductive tracts, demonstrating more intensive expression of ERbeta than ERalpha. However, as in other species, the efferent ductules remained the region of highest concentration of ERalpha.     

Immunolocalization of aquaporins 1, 2 and 7 in rete testis, efferent ducts, epididymis and vas deferens of adult dog

The transepithelial movement of water into the male reproductive tract is an essential process for normal male fertility. Protein water channels, referred to as aquaporins (AQPs), are involved in increasing the osmotic permeability of membranes. This study has examined the expression of AQP1, AQP2, and AQP7 in epithelial cells in adult dog efferent ducts, epididymis, and vas deferens. Samples of dog male reproductive tract comprising fragments of the testis, initial segment, caput, corpus and cauda epididymidis, and vas deferens were investigated by immunohistochemistry and Western blotting procedures to show the localization and distribution of the AQPs. AQP1 was noted in rete testis, in efferent ducts, and in vessels in the intertubular space, suggesting that AQP1 participated in the absorption of the large amount of testicular fluid occurring characteristically in the efferent ducts. AQP2 expression was found in the rete testis, efferent ducts and epididymis, whereas AQP7 was expressed in the epithelium of the proximal regions of the epididymis and in the vas deferens. This is the first time that AQP2 and AQP7 have been observed in these regions of mammalian excurrent ducts, but their functional role in the dog male reproductive tract remains unknown. Investigations of AQP biology could be relevant for clinical studies of the male reproductive tract and to technologies for assisted procreation. R.F.D. gratefully acknowledges a Fellowship from the Department of Anatomy, Institute of Biosciences, UNESP, Botucatu, SP, Brazil. This work was also funded by FAPESP (Sao Paulo State Research Foundation; grant 04/05578–1 to A.M.O. and grant 04/05579–8 to R.F.D.). This paper is part of the PhD Thesis presented by R.F.D. to the State University of Campinas – UNICAMP, Brazil.     

Immunohistochemical localization of taurine in the male reproductive organs of the rat.

The amino acid taurine has been implicated in several aspects of reproductive system physiology. However, its localization in these organs has not been previously analyzed. The aim of this study was to characterize its distribution in male rat reproductive organs by immunohistochemical methods. Taurine was localized in the smooth muscle cells of the tissues studied and in the skeletal fibers of the cremaster muscle. In the testis, taurine was found in Leydig cells, vascular endothelial cells, and other interstitial cells. No immunoreactivity was observed in the cells of the seminiferous tubules, either in germ cells at all spermatogenic stages or in Sertoli cells. However, peritubular myoid cells were immunostained. Most epithelial cells of the efferent ducts were immunolabeled, whereas the epithelial cells of the rete testis (extratesticular segments), epididymis (caput, corpus, and cauda regions), and ductus deferens were unstained. However, most epithelial cells from the intratesticular segments of the rete were immunopositive. Some cells identified as intraepithelial macrophages and lymphocytes, apical cells, and narrow cells were intensely immunolabeled. Regional differences in the distribution of these cell types along the ducts studied were also noted. The possible functional roles for taurine in these cells are discussed.     

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.     

Co-expression and interaction of cubilin and megalin in the adult male rat reproductive system

Cubilin is a peripheral membrane protein that cooperates with the endocytic receptor megalin to mediate endocytosis of ligands in various polarized epithelia. Megalin is expressed in the male reproductive tract where it has been implicated in the process of sperm membrane remodeling. A potential role for cubilin in the male reproductive tract has not been explored. Using RT-PCR, we found that cubilin and megalin mRNAs are expressed in the efferent ducts, corpus and cauda epididymis, and proximal and distal vas deferens. Immunohistological analysis revealed that cubilin was expressed in nonciliated cells of the efferent ducts, principal cells of the corpus and cauda epididymis and vas deferens. Immunogold EM showed cubilin in endocytic pits, endocytic vesicles, and endosomes of these cells. The expression profile of cubilin in the male reproductive tract was coincident with that of megalin except in principal cells of the caput epididymis. Double immunogold labeling showed that cubilin and megalin co-localized within the endocytic apparatus and recycling vesicles of efferent duct cells. Neither protein was found in lysosomes. Injection of RAP, an antagonist of megalin interaction with cubilin, reduced the level of intracellular cubilin in cells of the efferent ducts and vas deferens. In conclusion, cubilin and megalin are co-expressed in cells of the epididymis and vas deferens and the endocytosis of cubilin in these tissues is dependent on megalin. Together, these findings highlight the potential for a joint endocytic role for cubilin and megalin in the male reproductive tract.     

Histochemical evaluation of glycoconjugates in the male reproductive tract with lectin-horseradish peroxidase conjugates: I. Staining of principal cells and spermatozoa in the mouse

Several glycoconjugates are thought to bind spermatozoa as they pass through reproductive ducts. Paraffin sections of testis, ductuli efferentes, epididymis, and vas deferens of male mice were stained with ten different lectin-horseradish peroxidase conjugates to localize possible sites of synthesis and secretion of such glycoconjugates, based on the carbohydrate moieties in their constituent oligosaccharide side chains. Principal (columnar) cells lining the efferent ducts, germinal epithelium, and developing and maturing spermatozoa were examined with light microscopy. Staining of the Golgi and apical zones of cells was interpreted as evidence for synthesis and secretion of glycoconjugates. Principal cells synthesized and secreted glycoconjugates with sugar moieties as follows: sialic acid, all regions of the efferent ducts examined; the terminal disaccharide D-galactose- (beta 1----3) -N-acetyl-D-galactosamine, all regions of ducts except epididymis I; terminal alpha-D-galactosamine, some cells in epididymis III-V; N-acetyl-D-galactosamine, ductuli efferentes, epididymis I, II, and some cells in epididymis III-V; alpha-L-fucose, ductuli efferentes, vas deferens, and all regions of the epididymis except IV; N-glycosidic side chains, ductuli efferentes, vas deferens, and epididymis I, IV, and V. All of these sugar residues as well as N-acetyl-D-glucosamine were associated with the acrosomes and tails of spermatozoa throughout the ducts except for alpha-N-acetyl-D-galactosamine in epididymis I, and all occurred during one or more stages of spermiogenesis. The synthesis and secretion of glycoconjugates that bind to spermatozoa appear to involve more regions of the primary reproductive structures than was believed previously.     

FGF8 is essential for formation of the ductal system in the male reproductive tract

During development of the urogenital tract, fibroblast growth factor 8 (Fgf8) is expressed in mesonephric tubules, but its role in this tissue remains undefined. An evaluation of previously generated T-Cre-mediated Fgf8-deficient mice (T-Cre; Fgf8(flox/Δ2,3) mice), which lack Fgf8 expression in the mesoderm, revealed that the cranial region of the Wolffian duct degenerated prematurely and the cranial mesonephric tubules were missing. As a result, the epididymis, vas deferens and efferent ductules were largely absent in mutant mice. Rarb2-Cre was used to eliminate FGF8 from the mesonephric tubules but to allow expression in the adjacent somites. These mutants retained the cranial end of the Wolffian duct and formed the epididymis and vas deferens, but failed to elaborate the efferent ductules, indicating that Fgf8 expression by the mesonephric tubules is required specifically for the formation of the ductules. Ret knockout mice do not form the ureteric bud, a caudal outgrowth of the Wolffian duct and progenitor for the collecting duct network in the kidney, but they do develop the cranial end normally. This indicates that Fgf8, but not Ret, expression is essential to the outgrowth of the cranial mesonephric tubules from the Wolffian duct and to the development of major portions of the sex accessory tissues in the male reproductive tract. Mechanistically, FGF8 functions upstream of Lhx1 expression in forming the nephron, and analysis of Fgf8 mutants similarly shows deficient Lhx1 expression in the mesonephric tubules. These results demonstrate a multifocal requirement for FGF8 in establishing the male reproductive tract ducts and implicate Lhx1 signaling in tubule elongation.     

Expression of cysteine sulfinate decarboxylase (CSD) in male reproductive organs of mice

Cysteine sulfinate decarboxylase (CSD) is the rate-limiting biosynthetic enzyme of taurine, but it is still controversial whether the male reproductive organs have the function to synthesize taurine through CSD pathway. The present study was thus undertaken to detect CSD expression in male mouse reproductive organs by RT-PCR, Western blot and immunohistochemistry. The results show that CSD is expressed both at the mRNA and protein levels in the testis, epididymis and ductus deferens. The relative levels of both CSD mRNA and protein increase from the testis to the epididymis and to the ductus deferens. Immunohistochemical results demonstrate that the main cell types containing CSD are Leydig cells of testis, epithelial cells and some stromal cells throughout the efferent ducts, epididymis and ductus deferens. These results suggest that male genital organs have the function to produce taurine through the CSD pathway, although quantifying the relation of CSD expression to taurine synthesis and the exact functions of taurine in male genital organs still need to be elucidated in future studies.     

Segmental and cellular expression of aquaporins in the male excurrent duct

The male reproductive tract and accessory glands comprise a complex but interrelated system of tissues that are composed of many distinct cell types, all of which contribute to the ability of spermatozoa to carry out their ultimate function of fertilizing an oocyte. Spermatozoa undergo their final steps of maturation as they pass through the male excurrent duct, which includes efferent ducts, the epididymis and the vas deferens. The composition of the luminal environment in these organs is tightly regulated. Major fluid reabsorption occurs in efferent ducts and in the epididymis, and leads to a significant increase in sperm concentration. In the distal epididymis and vas deferens, fluid secretion controls the final fluidity of the luminal content. Therefore, the process of water movement in the excurrent duct is a crucial step for the establishment of male fertility. Aquaporins contribute to transepithelial water transport in many tissues, including the kidney, the brain, the eye and the respiratory tract. The present article reviews our current knowledge regarding the distribution and function of aquaporins in the male excurrent duct.     

Segmental and cellular expression of aquaporins in the male excurrent duct

The male reproductive tract and accessory glands comprise a complex but interrelated system of tissues that are composed of many distinct cell types, all of which contribute to the ability of spermatozoa to carry out their ultimate function of fertilizing an oocyte. Spermatozoa undergo their final steps of maturation as they pass through the male excurrent duct, which includes efferent ducts, the epididymis and the vas deferens. The composition of the luminal environment in these organs is tightly regulated. Major fluid reabsorption occurs in efferent ducts and in the epididymis, and leads to a significant increase in sperm concentration. In the distal epididymis and vas deferens, fluid secretion controls the final fluidity of the luminal content. Therefore, the process of water movement in the excurrent duct is a crucial step for the establishment of male fertility. Aquaporins contribute to transepithelial water transport in many tissues, including the kidney, the brain, the eye and the respiratory tract. The present article reviews our current knowledge regarding the distribution and function of aquaporins in the male excurrent duct.     

Species-specific expression of microsomal prostaglandin E synthase-1 and cyclooxygenases in male monkey reproductive organs

We investigated the tissue distribution and cellular localization of microsomal PGE synthase-1 (mPGES-1) and cyclooxygenase (COX)-1 and -2 in male monkey reproductive organs. Western blotting revealed that monkey mPGES-1 was expressed most intensely in the seminal vesicles, moderately in the testis, and weakly in the epididymis and vas deferens. The tissue distribution profile was quite different from those profiles for rats, rabbits, and pigs, e.g., rat mPGES-1 was the most abundant in the vas deferens, and the rabbit and pig enzymes, in the testis. Immunohistochemical staining with mouse monoclonal anti-human mPGES-1 antibody revealed that monkey mPGES-1 was localized in spermatogonia, Sertoli cells, and primary spermatocytes of testis and in epithelial cells of the epididymis, vas deferens, and seminal vesicles. In monkeys, COX-1 was localized in epithelial cells of the epididymis and vas deferens, whereas COX-2 was dominantly found in epithelial cells of the seminal vesicles.     

Microanatomy of the testes and testicular ducts of the butterfly lizard,Leiolepis ocellata Peters, 1971 (Reptilia: Squamata: Agamidae) during the active reproductive period

The microanatomy of the testes and testicular ducts (rete testis, ductuli efferentes, ductus epididymis and ductus deferens) of Leiolepis ocellata (Agamidae) was investigated using light microscopy including histochemistry. Each testis contains seminiferous tubules and interstitial tissues. The former house spermatogenic cells (spermatogonia A & B, preleptotene, primary and secondary spermatocytes, spermatids (steps 1–8) and spermatozoa) and Sertoli cells, while the latter comprise peritubular and intersitial tissues. The rete testis is an anastomosing duct, having intratesticular and extratesticular portions. The proximal region of ductuli efferentes has wider outer ductal and luminal diameters than those of the distal region. The convoluted ductus epididymis is subdivided into four regions (initial segment, caput, corpus and cauda), based on the ductal diameter, epithelium characteristics and cell components. The ductus deferens has the greatest diameter and is divided into the ductal and ampulla ductus deferens. The ductal portion is subdivided into the proximal and distal regions, based on the epithelium types and ductal diameters. The ampulla ductus deferens is a fibromuscular tube, having numerous mucosal folds projecting into the lumen. Spermiophagy is detectable in the ductus epididymis and ductus deferens. The present results contribute to improved fundamental knowledge on the microanatomy of the reptilian reproductive system.     

Role of epithelial cells of the male excurrent duct system of the rat in the endocytosis or secretion of sulfated glycoprotein-2 (clusterin)

The localization of sulfated glycoprotein-2 (clusterin; SGP-2) was investigated in the rete testis, efferent ducts, and epididymis of the rat using light (LM) and electron (EM) microscope immunocytochemistry. At the LM level, the epithelial cells of the rete testis and efferent ducts demonstrated an intense immunoperoxidase reaction over their apical and supranuclear regions, and sperm in the lumen of the efferent ducts were unreactive. In the EM, gold particles were found exclusively over the endocytic apparatus of these cells. In the proximal area of the epididymal initial segment, an insignificant immunostaining of epithelial cells and sperm was observed. However, the distal area of the initial segment showed a moderate staining over the epithelial principal cells and sperm, while in the intermediate zone of the epididymis a stronger reaction was observed over these cells. The strongest immunoperoxidase reaction was noted in the caput epididymidis, where it formed a distinct mottled pattern. Thus, while some principal cells were intensely stained, others were moderately or weakly stained; a few were completely unreactive. In the corpus and cauda epididymidis, the staining pattern was similar but not as intense. In the EM, only the secretory apparatus of these cells was found to be immunolabeled with gold particles. Sperm in the lumen of these different regions were also labeled. The epithelial clear cells were unreactive throughout the epididymis. Northern blot analysis substantiated these results and showed the presence of highest levels of SGP-2 mRNA in the caput epididymidis, especially in its proximal area, whereas increasingly lower levels were found in the corpus and cauda epididymidis. In summary, these results suggest that testicular SGP-2 dissociates from the sperm during passage through the rete testis and efferent ducts, where it is endocytosed by the epithelial cells lining these regions. In the epididymis, it is replaced by an epididymal SGP-2 that is secreted by the epithelial principal cells of the epididymis. Furthermore, in the epididymis, the principal cells appear to be in different functional states with respect to the secretion of epididymal SGP-2 within a given region of the duct as well as along the epididymal duct.     

Excurrent duct system of the male turtle Chrysemys picta

The epididymis and efferent duct system of the turtle Chrysemys picta were examined. Seminiferous tubules are drained by a series of ducts that form a rete exterior to the tunica albuginea. The rete is located lateral to the testis and consists of anastamosing tubules of varying diameters, lined by a simple epithelium consisting of squamous to cuboidal cells. The rete is highly vascularized. A series of tubules (efferent ductules) connect the rete to the epididymis proper. The efferent ductules are highly convoluted, running between the epididymal tubules and are of varying diameters. The simple columnar epithelium lining these tubules possesses tight junctions, with every third or fourth cell possessing long cilia that protrude into the lumen. The cytoplasm of these epithelial cells contains abundant mitochondria. In the central portion of the efferent ductule, epithelial cells possess granules that appear to be secreted into the lumen by an apocrine process. The epididymis proper is a single, long, highly convoluted tubule that receives efferent ductules along its entire length. It is lined by a pseudostratified epithelium containing several cell types. The most abundant cell (vesicular cell) lacks cilia, but has a darkly staining apical border due to numerous small vesicles immediately beneath the luminal membrane. The small vesicles appear to fuse with each other basally to form larger vesicles. These cells appear to have an absorptive function, and occasionally sperm are embedded in their cytoplasm. The second-most abundant cell is a basal cell found along the basement membrane. The number of these cells fluctuates throughout the year, being most abundant in late summer and early fall. A small narrow cell with an oval nucleus and darkly staining cytoplasm, extending from the basement membrane to the apical surface, is present in small numbers, particularly in the caudal regions of the epididymis. This cell is frequently found in association with another narrow cell having a rounded nucleus and abundant mitochondria in its cytoplasm.     

Histological and immunocytochemical study of deferens ducts in the Chinese rat snake (Zaocys dhumnades)

To investigate the relationship between structure and function of the deferens ducts in the Chinese rat snake (Zaocys dhumnades), morphological changes within an annual cycle were observed by routine histological techniques. Also, the correlation of androgen receptor (AR), estrogen receptor (ER), progesterone receptor (PR) and aromatase (Ar) expressions in the vas deferens and testis were studied immunohistochemically. To confirm that the sperm and the spherical structure existed in deferens ducts, we also used routine histological technique observed deferens ducts in the Striped-tailed rat-snake (Elaphe taeniura), Red-banded snake (Dinodon rufozonatum), and Tiger-spotted neck-troughed snake (Rhabdophis tigrina lateralis). The results showed that the deferens ducts of the Chinese Rat Snake were composed of efferent duct, epididymal duct and vas deferens. Efferent duct contained sperm from August-October, and the sperm were observed in the epididymal duct from August-the following January. Throughout the year (except July) a large number of sperm were present in the vas deferens where a previously unreported spherical structure formed by spermatids was observed, which showed no significant differences in the IOD values of AR-, ER-, PR- and Ar-immunoreactivities. Since the spermatids in the spherical structure were undergoing spermatogenesis and this phenomenon also existed in the Striped-tailed rat-snake and Red-banded snake, the term, seminiferous spherule, was named for this spherical structure This study demonstrated that the testis was the main site for snake spermiogenesis, and the seminiferous spherule in vas deferens was the other Both the epididymis and vas deferens stored sperm; however, the vas deferens was the main organ for sperm storage.     

High level of endostatin in epididymal epithelium: protection against primary malignancies in this organ?

Rete testis and epididymis are rare locations for primary tumors or metastasis. Assuming that this may be related to expression level of angiogenic inhibitors, we focused our study on the expression pattern of collagen 18/endostatin. In situ hybridization and immunohistochemistry for collagen 18 and endostatin were carried out on sections of human rete testis and epididymis as well as on epididymal adenoma and human testicular tissue with or without carcinoma in situ (CIS). In situ hybridization revealed strong expression of collagen 18 mRNA in rete testis, efferent ducts and epididymal duct. Immunostaining showed collagen 18 in epithelium and basement membrane as well as in blood vessels of rete testis. Further, in both efferent ducts and epididymal duct, collagen 18 was mainly localized in the basement membrane of these ducts and of the blood vessel wall. Endostatin immunostaining was localized in the epithelium of rete testis, efferent ducts and epididymal duct. This pattern of endostatin staining was absent in epididymal adenoma tissue while tumor associated blood vessels exhibited strong endostatin staining. No endostatin staining was detectable in normal germinal epithelium and CIS cells while Leydig cells exhibited strong endostatin staining. High endostatin expression in epididymis may protect this organ against tumor development. Gene therapeutic strategies providing high expression of endostatin in normal epithelia may be useful to prevent tumor development.     

Expression of villin in the mouse oviduct and the seminiferous ducts

Summary Villin, a 95-kD cytoskeletal protein selectively expressed in the microvilli of some absorptive cells was localized immunohistochemically in the oviduct and the seminiferous excretory ducts of the mouse. Villin was found in the proximal part of the oviduct, comprising the preampulla, ampulla, and part of the isthmus. Distal to the isthmus the oviductal cells lining the junctura and the intrauterine colliculus tubaris were devoid of villin. No villin could be detected in the uterine cells.Ductuli efferentes, connecting the rete testis with the epididymis were the only portion of the male seminiferous ductal system expressing villin. The cells lining the epididymis and the vas deferens were devoid of villin. These data show that villin is selectively expressed in male and female reproductive systems and that it is limited to anatomically defined proximal portions of the reproductive ducts.