Male Reproductive Ducts Research Articles

A possible highway system for the rapid delivery of sperm from the testis to the penis in the naked mole‐rat, Heterocephalus glaber

Gametogenesis is suppressed in most members of the eusocial naked mole-rat (NMR) colony, while the queen selects mainly one breeding male during her life span. Recently, it was reported that the NMR testicular organization seems to produce spermatozoa on demand after suppression of spermatogenesis during most of gestation. A Sertoli cell "pump" is then used to flush the spermatozoa into short tubuli recti and simplified rete testis to reach the excurrent duct system. We hypothesize that the components of this duct system are adapted for rapid delivery of spermatozoa to the penis and for numerous copulations with the queen. Therefore, the aim was to study the ultrastructure of the male NMR reproductive duct system using light microscopy and transmission electron microscopy. The NMR rete testis gives rise to six to eight efferent tubules joining the caput epididymis. The caput epididymis resembles that of other rodents but with less distinction in terms of histological zoning. The remainder of the epididymis is considerably reduced in length compared to other rodents. In contrast, the vas deferens epithelium is highly specialized in that a vast range of vesicles, often closely associated with the spermatozoa, were visible. The large ampulla is a factory for merocrine and apocrine secretions, producing even more diverse vesicles. The transitional epithelial cells of the bladder appear to secrete abundant mucous and the penis as well as its baculum is relatively small. We speculate that these modifications strongly suggest that the excurrent duct system has been simplified and adjusted to compensate for the absence of long maturation and storage of spermatozoa. We propose that these adaptations to the NMR reproductive tract are associated with a state of degenerative orthogenesis that was selected for due to the absence of sperm competition and apparently rapid delivery of spermatozoa from the testis.

Gross and microanatomy of the male reproductive duct system of the saltwater crocodile Crocodylus porosus.

Information on the morphology and histology of the male reproductive system of the Crocodylia species is necessary to determine the role of these tissues in the production of functional spermatozoa. Accordingly, in this study we examined the gross morphology and microanatomy of the testis and the male excurrent duct system through which spermatozoa pass before ejaculation. The data demonstrate that the reproductive system in male saltwater crocodiles comprises paired testes, which convey spermatozoa distally via the rete testis into an excurrent duct system comprising ductuli efferentes, ductuli epididymides, ductus epididymidis and ductus deferens. The epithelium delineating the male tract was dominated by non-ciliated and ciliated cells structured into a simple columnar lining of the ductuli efferentes and ductuli epididymides, through to the high pseudostratified columnar epithelium of the ductus epididymidis and ductus deferens. The morphology and histochemical staining of these ducts suggest their involvement in seminal fluid production and/or its modification, which likely contributes to the nourishment, protection and/or storage of crocodile spermatozoa. As a reflection of their common Archosaurs ancestry, the overall structural characteristics we describe for the crocodile male excurrent duct system share closer similarities to those of the Aves than other clades within the Reptilia class or Mammalia.

Transcription factor TAp73 and microRNA-449 complement each other to support multiciliogenesis.

Motile cilia serve vital functions in development, homeostasis, and regeneration. We recently demonstrated that TAp73 is an essential transcriptional regulator of respiratory multiciliogenesis. Here, we show that TAp73 is expressed in multiciliated cells (MCCs) of diverse tissues. Analysis of TAp73 mutant animals revealed that TAp73 regulates Foxj1, Rfx2, Rfx3, axonemal dyneins Dnali1 and Dnai1, plays a pivotal role in the generation of MCCs in male and female reproductive ducts, and contributes to fertility. However, the function of MCCs in the brain appears to be preserved despite the loss of TAp73, and robust activity of cilia-related networks is maintained in the absence of TAp73. Notably, TAp73 loss leads to distinct changes in ciliogenic microRNAs: miR34bc expression is reduced, whereas the miR449 cluster is induced in diverse multiciliated epithelia. Among different MCCs, choroid plexus (CP) epithelial cells in the brain display prominent miR449 expression, whereas brain ventricles exhibit significant increase in miR449 levels along with an increase in the activity of ciliogenic E2F4/MCIDAS circuit in TAp73 mutant animals. Conversely, E2F4 induces robust transcriptional response from miR449 genomic regions. To address whether increased miR449 levels in the brain maintain the multiciliogenesis program in the absence of TAp73, we deleted both TAp73 and miR449 in mice. Although loss of miR449 alone led to a mild ciliary defect in the CP, more pronounced ciliary defects and hydrocephalus were observed in the brain lacking both TAp73 and miR449. In contrast, miR449 loss in other MCCs failed to enhance ciliary defects associated with TAp73 loss. Together, our study shows that, in addition to the airways, TAp73 is essential for generation of MCCs in male and female reproductive ducts, whereas miR449 and TAp73 complement each other to support multiciliogenesis and CP development in the brain.

Ductal sex determination.

Females actively eliminate male reproductive ducts during mammalian embryogenesis

Molecular phylogeny of the leaf beetle subfamily Criocerinae (Coleoptera: Chrysomelidae) and the correlated evolution of reproductive organs

Phylogenetic relationships among major groups of Criocerinae were reconstructed using molecular data (mitochondrial cytochrome oxidase I and 12S rDNA, and nuclear histone 3). The monophyly of Criocerinae was consistently and robustly supported. The Lema group including Lema, Oulema and Neolema was recovered as a clade, with the latter two genera imbedded within Lema. The Lilioceris group was placed as the sister taxon of the Lema group, and the genus Crioceris was identified as the sister taxon of the Lilioceris + Lema groups. The monophyly and/or validity of Mecoprosopus Chûjô, 1951 and the subgenera Lema, Petauristes Latreille, 1829, Quasilema Monrós, 1960, Microlema Pic, 1932, and Bradyceris Chûjô, 1951 were not confirmed. The monophyly of the subgenus Lema except for the type species L. cyanea was supported by molecular and morphological data, and we termed it the cyanella clade. The present molecular phylogeny was compared with previous concepts with respect to the validity of each genus/subgenus. A revision of several genera is necessary. Based on the phylogenic result, the character evolution of the reproductive organs was analyzed. The ancestral states of this character system were parsimoniously reconstructed. Various shapes of the spermatheca were observed in the subfamily. A convoluted spermatheca evolved once, and reversals to the ancestral state took place several times independently. An elongation of a part of the intromittent organ also occurred several times independently. The length of the male and female reproductive ducts, which are in physical contact during copulation, showed a tight positive correlation even after removing phylogenetic effects. This strongly suggests coevolution between the male and female genital length.

MAPK8 and MAPK11 Modulate TGFB1-Induced Changes in Epithelial Function Across Human and Porcine Vas Deferens Epithelial Cells.

Transforming growth factor 1 (TGFB1) is associated with pulmonary disease progression in cystic fibrosis (CF) patients although the impact of TGFB1 on the male reproductive duct is unknown. Cystic fibrosis, the most common recessive genetic disease in Caucasians, is almost universally (>98%) associated with congenital bilateral absence of the vas deferens (CBAVD) resulting in male infertility although pulmonary and pancreatic manifestations, which affect slightly smaller proportions of the population (~85%), are more likely to lead to mortality. Male CF patients may with present infertility or subfertility without CBAVD. In addition, a small number of CBAVD cases occur that are not accompanied by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and various cases of idiopathic human male infertility or subfertility are reported that are not of testicular-based etiology. This study aimed to determine whether TGFB1 can alter human and porcine vas deferens epithelial cell physiology and to investigate the signal transduction pathway through which TGFB1 may induce changes in vas deferens epithelial cell function. Primary porcine (1°PVD) and human (1°HVD) vas deferens epithelial cell monolayers were exposed to either vehicle or TGFB1, for 24 and/or 72 hours, and then assessed in modified Ussing chambers. Vehicle-treated 1°PVD presented basal transepithelial resistance (RTE, a sensitive measure of epithelial barrier function) of 4800 Ohms/cm2, while paired 1°PVD exposed to TGFB1 (100 ng/ml) for 24 and 72 hours had 470 and 45 Ohms/cm2, respectively. 1°HVD exposed to TGFB1 (5 ng/ml) for 72 hours also revealed significant reductions in RTE. The ability of both 1°HVD and 1°PVD to respond with increases in short-circuit current (ISC, a sensitive measure of anion secretion) upon forskolin exposure (2 μM) was also impaired in TGFB1-exposed monolayers at 72 hours. To determine if protein kinases modulate the TGFB1 effect, 1°PVD monolayers were exposed to TGFB1 (5 ng/ml) for 24 hours, either in the absence or presence of selective inhibitors of mitogen-activated protein kinases 1 and 3 (MAPK1/3, previously known as ERK1/2), MAPK8 (previously known as JNK-1), MAPK11 (previously known as p38-MAPK) and phosphoinositide-3-kinase (PIK3). Outcomes suggest that SP600125, a selective MAPK8-inhibitor (10 μM), and SKF86002 (10 μM), a selective MAPK11-inhibitor (10 μM), are able to reduce the decreases in RTE induced by TGFB1. These data suggest that both human and porcine vas deferens epithelial cells respond functionally to activation of the TGFB1 receptor in vitro with a significant reduction in epithelial barrier function. Thus, TGFB1 signaling seems to lead to a loss of cell-cell association that could lead to a change in tissue architecture that may ultimately result in destruction of the duct. (Supported by NIH HD058398 and RR017686) (platform)

Purinergic agonists flex vas deferens muscle

The vas deferens is described typically as a muscular tube that functions as a conduit to move sperm from the epididymis to the urethra. A growing body of evidence, however, shows that the system is far more complex. Smooth muscle tone and contractions are affected by a number of neuocrine, endocrine and perhaps lumicrine agents. Likewise, epithelial activity is modified by a similar host of agents. Stimulation of the hypogastric nerve, which innervates the male reproductive ducts, results in the co-release of noradrenaline, ATP, and other neurotransmitters that induce or modulate smooth muscle contraction and can induce epithelial ion transport. In fact, it has been suggested that purinergic receptors in the reproductive duct might be targeted for the development of non-steroidal male contraceptives (Gur et al. 2007). Thus, there is great interest in determining regulatory cascades that link purinergic stimulation to smooth muscle contraction or relaxation. One caveat in exploiting purinergic pathways to manage male fertility is the apparently conflicting observations that ATP exposure can, depending upon conditions, lead to either smooth muscle contraction or relaxation. Thus, multiple receptors and signalling cascades are probably involved in these responses. Both ionotropic P2X and metabotropic P2Y receptors are present on vas deferens smooth muscle cells with rapid muscle contraction typically associated with P2X-mediated Ca2+ entry. The cascade accounting for relaxation appears to be more complex. In a recent issue of The Journal of Physiology, Ruan et al. (2008) provide keen insight on a mechanism that probably contributes to muscle relaxation, in vitro. Their work builds on the observation that vas deferens epithelium contributes to the response of smooth muscle to adrenergic stimuli (Okpalaugo et al. 2002). This observation suggests that vas deferens smooth muscle activity can be modified by paracrine agents released from the epithelium. It is becoming more widely recognized that neurotransmitters and hormones can modify the activity of epithelial cells lining the epididymes and vas deferens. Indeed, neurotransmitters, steroid hormones, peptide hormones and autocoids have been shown to modify epithelial ion transport. HCO3− secretion is particularly important because it initiates and supports increased sperm motility. Importantly, noradrenaline, ATP and adenosine have been shown to induce anion secretion. The Ruan paper adds purinergic modulation of smooth muscle tone to the activities probably mediated by the epithelium lining the reproductive duct. Prostaglandin E2 is a key element in the epithelium-dependent response to ATP. This observation has far-reaching impact because prostaglandin H synthase 2 (PGHS2; formerly known as COX2) expression in vas deferens epithelial cells is dependent upon testosterone. In both rats (McKanna et al. 1998) and humans (Kirschenbaum et al. 2000), vas deferens epithelial PGHS2 expression correlates with serum testosterone. PGHS2 immunoreactivity is present during gestation and following puberty, but absent pre-pubertally or following castration. Recently, Pierucci-Alves & Schultz (2007) demonstrated that testosterone exposure enhances bradykinin-induced vas deferens epithelial anion secretion in vitro, a response mediated by prostaglandins. Thus, testosterone-induced epithelial PGHS2 expression provides the basis for androgen-dependent sperm development and delivery. The results provided by Ruan and colleagues are the foundation of a model that brings many seemingly disparate elements together with the culmination of viable sperm delivery. ATP released from the hypogastric nerve can rapidly promote smooth muscle contraction by the activation of P2X receptors while co-released noradrenaline can promote a sustained response by activating α1 receptors on smooth muscles. These same neurotransmitters can affect epithelial HCO3− secretion by interacting with epithelial P2Y and β2 receptors, respectively. In epithelial cells exposed to testosterone, PGHS2 can be stimulated downstream from the P2Y receptor resulting in PGE2 production. PGE2 then interacts with sperm to promote motility, with prostanoid receptors on epithelial cells to further enhance anion secretion, and with prostanoid receptors on adjacent smooth muscle cells to promote hyperpolarization and smooth muscle relaxation. Thus, the work presented in this issue provides compelling evidence that the vas deferens is much more that just a muscular tube. The vas deferens is a complex tissue in which many component parts contribute to the timely delivery of mature active sperm. Dr Schultz receives research support from the National Institutes of Health (R01HD058398).

Bradykinin-Stimulated Cyclooxygenase Activity Stimulates Vas Deferens Epithelial Anion Secretion In Vitro in Swine and Humans1

Epithelia lining the male reproductive duct modulate fertility by altering the luminal environment to which sperm are exposed. Although vas deferens epithelial cells reportedly express high levels of cyclooxygenases (Ptgs), and activation of bradykinin (BK) receptors can lead to upregulation of PTGS activity in epididymal epithelia, it remains unknown whether BKs and/or PTGSs have any role in modulating epithelial ion transport across vas deferens epithelia. Porcine and human vas deferens epithelial cell primary cultures and the PVD9902 cell line responded to lysylbradykinin with an increase in short circuit current (I SC; indicating net anion secretion), an effect that was 60%-93% reduced by indomethacin. The BK effect was inhibited by the B2 receptor subtype (BDKRB2) antagonist HOE140, whereas the B1 receptor subtype agonist des-Arg9-BK had no effect. BDKRB2 immunoreactivity was documented in most epithelial cells composing the native epithelium and on Western blots derived from cultured cells. Gene expression analysis revealed that the PTGS2 transcript is 20 times more abundant than its PTGS1 counterpart in cultured porcine vas deferens epithelia and that BDKRB2 mRNA is likewise highly expressed. Subsequent experiments revealed that prostaglandin E2, 1-OH prostaglandin E1 (prostaglandin E receptor 4 [PTGER4] agonist) and butaprost (PTGER2 agonist) increase I SC in a concentration-dependent manner, whereas sulprostone (mixed PTGER1 and PTGER3 agonist) produced no change in I SC. These results demonstrate that autacoids can affect epithelial cells to acutely modulate the luminal environment to which sperm are exposed in the vas deferens by enhancing PTGS activity, leading to the production of prostaglandins that act at PTGER4 and/or PTGER2 to induce or enhance anion secretion.

Expression of Core Clock and Output Genes in the Male Reproductive Ducts of Mice.

Expression of Core Clock and Output Genes in the Male Reproductive Ducts of Mice.

Determination of ions that are actively transported across porcine vas deferens epithelia

An appropriate fluid environment is required for sperm development, storage and activation, although the underlying mechanisms to account for electrolyte secretion into the male reproductive duct are not fully defined. Radiotracer flux experiments were conducted to test for unidirectional and net Na+, Cl−, and K+ transport across epithelial cells that were isolated from porcine vas deferens and grown in culture. Epithelial monolayers were exposed to the corticosteroid hormone dexamethasone for 72 hours before being mounted in modified Ussing flux Chambers for ion transport analysis. The apical and basolateral aspects of the epithelia were separately exposed, in paired monolayers, to tracer amounts of 22Na+, 36Cl−, or 86Rb+. Sampling was conducted over twenty minute periods in four cumulative conditions: basal, amiloride, forskolin, and bumetanide. Samples were analyzed using scintillation fluorimetry. Results indicate that amiloride sensitive Na+ absorption is present at the outset of sampling. Subsequently, forskolin was shown to stimulate bumetanide sensitive Cl− secretion across these epithelia. No net 86Rb+ flux was observed, which indicates no net K+ movement. Na+ and Cl− flux may not fully account for the observed short circuit current. Thus, additional studies are required to test for the contribution of HCO3− to stimulated secretion, which may contribute to sperm activation.

Morphology of the male reproductive ducts of Clibanarius erythropus (Anomura Diogenidae)

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Fine structure of the male reproductive ducts, vagina and seminal receptacle of Cyathocephalus truncatus (Cestoda: Spathebothriidea)

Fine structure of the vas efferens, vas deferens, ejaculatory duct with accessory glands and vagina with seminal receptacle is described in the spathebothriidean tapeworm, Cyathocephalus truncatus (Pallas, 1781) Kessler, 1868. The numerous well-developed prostate glands are characterised by having secretory granules with an electron-dense core surrounded by a matrix of lower electron density. Coalescence of the outer part of the granules with each other takes place in the terminal end of the secretory ducts. The position of prostate glands around the proximal part of the cirrus pouch and terminating in the ejaculatory duct is a characteristic feature of the Spathebothriidea. Up to 20 closely arranged muscle layers make up the muscular cirrus pouch wall with 4 well-developed muscular layers in the ejaculatory duct and cirrus. Both the cirrus and the vagina are covered with the same uniform cone-shaped microtriches. The vagina has an extensive seminal receptacle. All of these structures are well-adapted to insure successful sperm transfer involving ejaculation and storage, probably for both self- and cross-insemination. Cyathocephalus truncatus has a cirrus similar to that of the monozoic, progenetic caryophyllidean, Archigetes sieboldi and well-developed prostate glands like those of the polyzoic pseudophyllidean, Diphyllobothrium latum. The ultrastructural aspects of the male and female reproductive system of C. truncatus are compared with those of other tapeworms.

Ultrastructural characters of the spermatozoon of the cestode Corallobothrium solidum Fritsch, 1886 (Cestoda: Proteocephalidea), a parasite of the electric catfish Malapterurus electricus

The fine structure of the mature spermatozoon of the corallobothriine tapeworm Corallobothrium solidum Fritsch, 1886 (Cestoda: Proteocephalidea) from the electric catfish Malapterurus electricus from the Nile River in Egypt was studied by transmission electron microscopy for the first time. The filiform spermatozoon of C. solidum contains two axonemes of unequal length and a typical 9 + "1" trepaxonematan pattern. A single helicoidal crested body (30-200 nm thick) is localized at the anterior extremity of the gamete. The cortical microtubules line the periphery of the cell, largely parallel to the long axis of the spermatozoon and exhibiting signs of twisting at the beginning of region II. The nucleus, in the form of an electron-dense (largely in gametes of testes) and/or fibrous cord (largely in gametes from male reproductive ducts and seminal vesicle), coils in a spiral through the middle part (region III) of the spermatozoon. The cytoplasm contains electron-dense granules in regions II, III and partly in region IV. The cytoplasm of some spermatozoa exhibits an apparently higher electron-density at the end of the nucleated region (III), and continuously toward the middle part of region IV. The anterior and posterior extremities of the spermatozoa have a single axoneme. The ultrastructural features of the mature spermatozoon of C. solidum mostly coincide with those of the spermatozoon of other proteocephalideans, especially the gangesiine Electrotaenia malopteruri parasitizing the same host.

Morphology of the male reproductive duct system of Caiman crocodilus (Crocodylia, Alligatoridae)

The male reproductive duct system of Caiman crocodilus in different reproductive stages was studied using light and electron microscopy, to determine whether shared morphological features exist between Crocodylia and Aves, in concurrence with the Archosauria hypothesis. The sexual duct system of Caiman crocodilus is constituted of the rete testis, ductuli efferentes, ductuli epididymides, ductus epididymidis, and ductus deferens. The morphology and histochemical properties of these ducts suggest their involvement in seminal fluid production and/or its modification. Three types of non-ciliated cells were identified along the duct system. 1. The noncliated cells of the ductuli efferentes contain electron dense worm-like structures and coated vesicles, both related to absorptive processes, as has been suggested in Aves. 2. The non-ciliated cells of the ductuli epididymides have apical electron dense granules suggesting a secretory role, and 3. The non-ciliated cells of the ductus epididymidis and ductus deferens did not exhibit conspicuous storage of secretory material, but have a prominent rough endoplasmic reticulum content indicating active protein production. The occurrence of abundant secretory granules in the epithelial cells of the distal ductus deferens during non-reproductive stages suggests its participation in the removal of luminal debris when the reproductive season ends. Additional ducts were observed running along the ductus deferens; they shared morphological characteristics with the ductuli epididymides. The maximum diameter and therefore the greatest sperm accumulation of the excurrent ducts were observed during the initial testicular regression. The comparative analysis suggests that the male reproductive system of the Crocodylia exhibits structural characteristics nearer to those of Aves than to Lepidosauria, Testudines, and Mammalia, additional data that support an Aves and Crocodylia sister group relationship.

Intranasal immunization with C. muridarum major outer membrane protein (MOMP) and cholera toxin elicits local production of neutralising IgA in the prostate

Successful control of sexually transmitted diseases (STDs) through vaccination will require the development of vaccine strategies that target protective immunity to both the female and male reproductive tracts (MRT). In the male, the immune privileged nature of the male reproductive tract provides a barrier to entry of serum immunoglobulins into the male reproductive ducts, thereby preventing the induction of protective immunity using conventional injectable vaccination techniques. In this study we investigated the potential of intranasal (IN) immunization to elicit anti-chlamydial immunity in BALB/c male mice. Intranasal immunization with Chlamydia muridarum major outer membrane protein (MOMP) admixed with cholera toxin (CT) resulted in high levels of MOMP-specific IgA in prostatic fluids (PF) and MOMP-specific IgA-secreting cells in the prostate. Prostatic fluid IgA inhibited in vitro infection of McCoy cells with C. muridarum. Using RT-PCR we also show that mRNA for the polymeric immunoglobulin receptor (PIgR), which transports IgA across mucosal epithelia, is expressed only in the prostate but not in other regions of the male reproductive ducts upstream of the prostate. These data suggest that using intranasal immunization to target IgA to the prostate may protect males against STDs while at the same time maintaining the state of immune privilege within the MRT.

Intranasal immunization with C. muridarum major outer membrane protein (MOMP) and cholera toxin elicits local production of neutralising IgA in the prostate

Successful control of sexually transmitted diseases (STDs) through vaccination will require the development of vaccine strategies that target protective immunity to both the female and male reproductive tracts (MRT). In the male, the immune privileged nature of the male reproductive tract provides a barrier to entry of serum immunoglobulins into the male reproductive ducts, thereby preventing the induction of protective immunity using conventional injectable vaccination techniques. In this study we investigated the potential of intranasal (IN) immunization to elicit anti-chlamydial immunity in BALB/c male mice. Intranasal immunization with Chlamydia muridarum major outer membrane protein (MOMP) admixed with cholera toxin (CT) resulted in high levels of MOMP-specific IgA in prostatic fluids (PF) and MOMP-specific IgA-secreting cells in the prostate. Prostatic fluid IgA inhibited in vitro infection of McCoy cells with C. muridarum . Using RT-PCR we also show that mRNA for the polymeric immunoglobulin receptor (PIgR), which transports IgA across mucosal epithelia, is expressed only in the prostate but not in other regions of the male reproductive ducts upstream of the prostate. These data suggest that using intranasal immunization to target IgA to the prostate may protect males against STDs while at the same time maintaining the state of immune privilege within the MRT.

Restricted entry of IgG into male and female rabbit reproductive ducts following immunization with recombinant rabbit PH-20.

Successful immunocontraception using sperm antigens is dependent on achieving sufficient sperm-specific antibody in the reproductive ducts to prevent fertilization. The blood: luminal barrier of the male and female reproductive ducts must be overcome for this to occur. We have, therefore, investigated the relative titers of antigen-specific immunoglobulin G (IgG) in luminal fluids collected from male and female rabbit reproductive ducts following immunization with recombinant rabbit PH-20 (rPH-20). Male and female rabbits were immunized subcutaneously with rPH-20 in Freund's adjuvant. Reproductive tract fluids and plasma were collected and assayed for specific IgG by enzyme-linked immunoabsorbent assay (ELISA). Plasma anti-rPH-20 antibodies were tested for their ability to inhibit in vitro fertilization. Plasma rPH-20-specific IgG titers of > 21 x 106 were induced in bucks. Antibody levels in the rete testis and cauda epididymidis fluids were only 0.026 and 0.168% of plasma levels, respectively. Plasma IgG titers were > 30 x 10(6) in does, but antibody levels in free flow vaginal fluid, free flow uterine fluid and free flow oviduct fluid were only 0.016, 0.078 and 0.072% of plasma levels, respectively. Induction of ovulation by administration of human chorionic gonadotrophin (hCG) significantly increased rPH-20-specific IgG only in free flow vaginal fluids. Plasma antibody from immunized rabbits inhibited in vitro fertilization but conception rates following mating of rPH-20 immunized male to untreated female rabbits were not affected. The IgG antibody entry into the reproductive ducts of both male and female rabbits is restricted to less than 0.2% of levels induced in plasma following subcutaneous immunization. This finding raises doubts about the suitability of rPH-20 to induce immunocontraception in rabbits using strategies optimized for induction of a serum antibody response. Whether mucosal immunization strategies can achieve this remains to be tested.

Presence of two neuropeptides in the fusiform ganglion and reproductive ducts of Octopus vulgaris: FMRFamide and gonadotropin-releasing hormone (GnRH).

We have found evidence of FMRFamide-like and cGnRH-I-like immunoreactivity in the central nervous system (CNS) and in the reproductive ducts of both female and male cephalopod Octopus vulgaris. Cell bodies and fibers were immunolocalized in the fusiform ganglion from which the nerves that reach the female and male reproductive ducts arise. FMRFamide-like and cGnRH-I-like immunoreactive nerve endings were present in the oviduct, and in the oviducal gland of the female and in the seminal vesicle of the male. The GnRH-like peptide from the reproductive ducts has been partially characterized by HPLC. The retention time of the Octopus vulgaris GnRH-like peptide was similar to the retention time of cGnRH-I. Based on these observations we suggest that FMRFamide-like and a novel GnRH-like peptide are involved in the control of reproductive ducts of Octopus vulgaris. One possibility is that the peptides affect gamete transport. Another possibility is that they regulate secretory products such as mucus and mucilaginous substances from the oviducal gland and the seminal vesicle. Our data provide further evidence to support the hypothesis of the existence of a central and peripheral peptidergic control of reproduction of Octopus vulgaris.

Female development in mammals is regulated by Wnt-4 signalling.

In the mammalian embryo, both sexes are initially morphologically indistinguishable: specific hormones are required for sex-specific development. Mullerian inhibiting substance and testosterone secreted by the differentiating embryonic testes result in the loss of female (Mullerian) or promotion of male (Wolffian) reproductive duct development, respectively. The signalling molecule Wnt-4 is crucial for female sexual development. At birth, sexual development in males with a mutation in Wnt-4 appears to be normal; however, Wnt-4-mutant females are masculinized-the Mullerian duct is absent while the Wolffian duct continues to develop. Wnt-4 is initially required in both sexes for formation of the Mullerian duct, then Wnt-4 in the developing ovary appears to suppress the development of Leydig cells; consequently, Wnt-4-mutant females ectopically activate testosterone biosynthesis. Wnt-4 may also be required for maintenance of the female germ line. Thus, the establishment of sexual dimorphism is under the control of both local and systemic signals.

Reduction in Penis Size and Plasma Testosterone Concentrations in Juvenile Alligators Living in a Contaminated Environment

The development of the male reproductive ducts and external genitalia in vertebrates is dependent on elevated androgen concentrations during embryonic development and the period of postnatal growth. We have observed that a population of juvenile alligators living on Lake Apopka exhibit significantly smaller penis size (24% average decrease) and lower plasma concentrations of testosterone (70% lower concentrations) when compared to animals of similar size on Lake Woodruff. In addition to smaller phalli, no relationship exists between plasma testosterone concentrations and penile size in males from Lake Apopka, whereas a positive relationship exists for males from Lake Woodruff. The alligators on Lake Apopka are known to have elevated concentrations of the antiandrogenic DDT breakdown productp,p′-DDE stored in their fat. We suggest a number of hypotheses that could explain the modification in the phenotype of the juvenile male living in Lake Apopka. These modifications in phenotype include a smaller penis size, lower plasma androgen concentrations, and lack of responsiveness of the penis to the plasma androgens present.