Epididymal embryonic development harbors TLR4/NFKB signaling pathway as a morphogenetic player.

The Wolffian duct (WD) is an embryonic tissue that undergoes androgen-induced morphological changes to become the epididymis. Toll-like receptor 4 (TLR4)- and nuclear factor kB (NFKB)-induced effectors are expressed in the adult epididymis and represent important players in epididymal innate immune responses. TLR4/NFKB signaling pathway is evolutionarily conserved and plays a critical morphogenetic role in several species; however, its function during WD morphogenesis is unknown. We hypothesized that TLR4/NFKB pathway plays a role during WD development. Here we examined TLR4 expression and regulation of TLR4-target genes during rat WD morphogenesis between embryonic days (e) 17.5-20.5. The functionality of TLR4/NFKB signaling was examined using WD organotypic cultures treated with lipopolysaccharide (LPS) from E. coli (TLR4 agonist) and PDTC (NFKB inhibitor). TLR4 was detected at mRNA level in e17.5 (uncoiled duct) and e20.5 (coiled duct) WDs, and spatio-temporal changes in TLR4 immunoreactivity were observed between these two time points. Expression level analysis of a subset of TLR4-regulated genes showed that TLR4/NFKB pathway was activated after exposure of cultured WD to LPS (4 h), an event that was abrogated by PDTC. Long-term exposure of cultured WDs to LPS (96 h) resulted in dysregulations of morphogenetic events and LAMA1 immunodistribution changes, suggesting the extracellular matrix at the intersection between WD morphogenesis and balance of innate immune components. Our results unveil the epididymal morphogenesis as an event equipped with TLR4/NFKB signaling components that may serve developmental functions, and eventually transition to host defense function when the fetus is exposed to an infectious or noninfectious threat.

Morphology and histology of the male reproductive tract of Caecilia thompsoni (amphibia: Gymnophiona).

We studied the male reproductive tract of individuals of different body sizes of Caecilia thompsoni to describe morphological characteristics in comparison to other Gymnophiona. The reproductive tract consists of paired testes segmented into chains of primary and secondary lobes, sperm ducts that empty to Wolffian ducts, the cloaca that receives the Wolffian ducts and possesses a phallodeum. Müllerian ducts are present and develop into paired glands that empty into the cloacal urodeum. Testicular secondary lobes contain lobules with cysts of the entire germinal cell line, whereas primary lobes, in the terminal ends of the chains, only have spermagonia, Sertoli cells, and connective tissue. The smallest individual examined (21 cm body length) was immature and only possessed a few testicular primary lobes. Once the individuals reach sexual maturity, the morphological characteristics are quite consistent at macroscopic and histological level among males of very different body sizes. The histological features of the Wolffian and Müllerian glands suggest a complementary secretory role between the two ducts. In the cloaca we found the propulsor muscle, venous sinuses, and blind sacs in the phallodeum, which differentiate C. thompsoni from other species of the genus. Despite these slight differences, the general morphological characteristics, both macroscopic and microscopic, of the reproductive tracts of adult males of C. thompsoni follow the pattern known for the reproductively active males of Gymnophiona.

Quiste de Gartner de localización uterina / Gartner's cyst of uterine location

RESUMEN Los quistes de los conductos de Gartner, generalmente pequeños, benignos y asintomáticos, son vestigios del canal mesonéfrico de Wolff. Representan el 11 % de los quistes vaginales, esta es su localización más frecuente según la literatura consultada. Se presentó un caso operado en el Hospital Militar de Matanzas "Dr. Mario Muñoz Monroy", de localización en la cara posterior del istmo uterino (AU).

ABSTRAC Gartner's duct cyst, mostly little, benign and asymptomatic, are vestiges of the Wolffian mesonephric duct representing 11 % of the vaginal cysts; this location is the most frequently reported and published one up to date. The authors presented the case of a patient who underwent a surgery in the Military Hospital "Dr. Mario Muñoz Monroy¨ with a cyst in the posterior side of the uterine isthmus (AU).

We, the developing rete testis, efferent ducts, and Wolffian duct, all hereby agree that we need to connect.

BACKGROUND: The mechanisms by which the rete testis joins the efferent ducts, which joins the Wolffian duct during development, are not known. Mouse and chick models have been helpful in identifying genes that are important for the development of each part, but genes have not been identified as to those that play a role in the joining of each part. Clinical implications of the failure of the male reproductive tract to form a fully functional conduit for spermatozoa are not trivial. Epididymal disjunction, the failure of the efferent ducts to join the testis, is one of several epididymal anomalies that have been observed in some boys who were cryptorchid at birth. OBJECTIVE: A systematic review of studies focusing on the morphogenesis of the mesonephric duct and mesonephric tubules in different species, and identification of clinical issues should there be failure of these tissues to develop. DESIGN: PubMed and GUDMAP databases, and review of books on kidney development were searched for studies reporting on the mechanisms of morphogenesis of the kidney and epididymis. MAIN OUTCOMES MEASURE(S): Gaps in our knowledge were identified, and hypotheses coupled with suggestions for future experiments were presented. RESULTS: A total of 64 papers were identified as relevant, of which 53 were original research articles and 11 were book chapters and reviews covering morphogenesis and clinical issues. Investigators utilized multiple species including, human, mouse, chick, Xenopus, bovine, and sheep. CONCLUSION: Fundamental understanding of the morphogenesis of the male reproductive tract is limited, especially the morphogenesis of the rete testis and efferent ducts. Therefore, it is not surprising that we do not understand how each part unites to form a whole. Only one mechanism of joining of one part of the tract to another was identified: the joining of the Wolffian duct to the cloaca via controlled apoptosis.

Development of urogenital system in the Spix cavy: A model for studies on sexual differentiation.

This study documented, for the first time, the morphological patterns of differentiation of male and female genital organs of Spix cavy (Galea spixii) using histological and ultrastructural analyses, with immuno-localization of steroidogenic enzymes, cytochromes P450 aromatase (P450arom) and 17α-hydroxylase/17, 20-lyase (P450c17), involved in the synthesis of estrogens and androgens respectively throughout fetal sexual development. Undifferentiated gonads of Spix cavy develop into ovaries in females after 25 days of gestation (DG), exhibiting P450arom immunoreactivity. After 25 DG, paramesonephric ducts develop and form oviducts, uterine horns and cranial portion of the vagina. The caudal portion of the vagina originates from the urogenital sinus, and a vaginal closure membrane is present at the end of gestation. Partial channeling of the urethra into the clitoris occurs after 40 DG, but complete channeling never occurs. A preputial meatus emerges near the tip of organ. In males, undifferentiated gonads develop into testes at 25 DG and develop immunoreactivity for P450c17, which is required for androgens synthesis and likely maintenance of mesonephric ducts. Mesonephric ducts develop subsequently, forming the epididymis and ductus deferens. The pelvic urethra develops after 25 DG with channeling into the penis occurring around 30 DG. This is the first morphological study describing the process of sexual differentiation during gestation in a hystricomorph rodent and one of the most comprehensive analyses conducted in any mammal. Male genital organ development follows the general pattern described in other domestic mammals, but does not include formation of the baculum as occurs in mice and rats. In females, clitoral development includes partial canalization by the urethra and development of a preputial meatus. Further studies are required to clarify the mechanisms involved in the differentiative processes described.

Remaining uterine mesonephric duct cyst in female dog (Canis familiaris) – first case report in Brazil / Cisto de ducto mesonéfrico uterino remanescente em cadela (Canis familiaris) - primeiro relato de caso no Brasil / Quiste remaneciente del ducto mesonéfrico uterino en perra (Canis familiaris) – primero relato del caso en Brasil

The aim of work was to describe a remaining uterine mesonephric duct cyst in female Pinscher dog, with 8 years old. The main complaint of the owner was no heat at least 18 months. Clinical examination revealed presence of cysts in all teats, confirmed by cytopathologic exam. Haemogram, serum biochemical exams, urinalysis, radiographs of the thorax and abdominal ultrasound were performed and no changes were observed. During the ovaryhysterectomy was observed endometrial hyperplasia and the histopathologic diagnosis was remaining uterine mesonephric duct cyst associated with discrete endometrial hyperplasia. Was concluded that adequate histopathologycal identification of the uterine mesonephric duct cyst is crucial so do not mistake with neoplasia.

O objetivo do trabalho foi descrever um caso de cisto de ducto mesonéfrico remanescente uterino em cadela da raça Pinscher, 8 anos de idade. A principal queixa do proprietário foi ausência de cio com duração de 18 meses. No exame físico evidenciou-se presença de cistos em todos os tetos, confirmado pelo exame citopatológico. Foi realizado hemograma, exames de bioquímica sérica, urinálise, exame radiográfico do tórax e ultrassom abdominal, e não foram observadas alterações. Durante o procedimento de ovário-histerectomia, foi observada hiperplasia endometrial e o diagnóstico histopatológico foi de cisto de ducto mesonéfrico remanescente uterino associado à hiperplasia endometrial discreta. Concluiu-se que a identificação histopatológica adequada do cisto de ducto mesonéfrico uterino é crucial para que o mesmo não seja confundido com neoplasia.

El objetivo del trábalo fue describir un caso de quiste remaneciente del ducto mesonéfrico uterino en perra da raza Pinscher, 8 años de edad. La principal queja del propietario fue ausencia del cio con duración de 18 meses. El examen físico reveló una presencia de quistes en los techos, confirmado por examen citopatológico. Se realizaron hemograma, pruebas bioquímicas sérica, análisis de orina, radiografías de tórax y ecografía abdominal, y no se observaron cambios. Durante ovario histerectomía se observó hiperplasia endometrial y el diagnóstico histopatológico se fue quiste remaneciente del ducto mesonéfrico uterina asociado a la hiperplasia endometrial discreta. Se concluyó que la identificación histopatológico adecuada del ducto mesonéfrico uterina es crucial para que no se confunda con neoplasia.

Remaining uterine mesonephric duct cyst in female dog (Canis familiaris) first case report in Brazil / Cisto de ducto mesonéfrico uterino remanescente em cadela (Canis familiaris) - primeiro relato de caso no Brasil / Quiste remaneciente del ducto mesonéfrico uterino en perra (Canis familiaris) primero relato del caso en Brasil

The aim of work was to describe a remaining uterine mesonephric duct cyst in female Pinscher dog, with 8 years old. The main complaint of the owner was no heat at least 18 months. Clinical examination revealed presence of cysts in all teats, confirmed by cytopathologic exam. Haemogram, serum biochemical exams, urinalysis, radiographs of the thorax and abdominal ultrasound were performed and no changes were observed. During the ovaryhysterectomy was observed endometrial hyperplasia and the histopathologic diagnosis was remaining uterine mesonephric duct cyst associated with discrete endometrial hyperplasia. Was concluded that adequate histopathologycal identification of the uterine mesonephric duct cyst is crucial so do not mistake with neoplasia.(AU)

O objetivo do trabalho foi descrever um caso de cisto de ducto mesonéfrico remanescente uterino em cadela da raça Pinscher, 8 anos de idade. A principal queixa do proprietário foi ausência de cio com duração de 18 meses. No exame físico evidenciou-se presença de cistos em todos os tetos, confirmado pelo exame citopatológico. Foi realizado hemograma, exames de bioquímica sérica, urinálise, exame radiográfico do tórax e ultrassom abdominal, e não foram observadas alterações. Durante o procedimento de ovário-histerectomia, foi observada hiperplasia endometrial e o diagnóstico histopatológico foi de cisto de ducto mesonéfrico remanescente uterino associado à hiperplasia endometrial discreta. Concluiu-se que a identificação histopatológica adequada do cisto de ducto mesonéfrico uterino é crucial para que o mesmo não seja confundido com neoplasia.(AU)

El objetivo del trábalo fue describir un caso de quiste remaneciente del ducto mesonéfrico uterino en perra da raza Pinscher, 8 años de edad. La principal queja del propietario fue ausencia del cio con duración de 18 meses. El examen físico reveló una presencia de quistes en los techos, confirmado por examen citopatológico. Se realizaron hemograma, pruebas bioquímicas sérica, análisis de orina, radiografías de tórax y ecografía abdominal, y no se observaron cambios. Durante ovario histerectomía se observó hiperplasia endometrial y el diagnóstico histopatológico se fue quiste remaneciente del ducto mesonéfrico uterina asociado a la hiperplasia endometrial discreta. Se concluyó que la identificación histopatológico adecuada del ducto mesonéfrico uterina es crucial para que no se confunda con neoplasia.(AU)

Novel androgen-induced activity of an antimicrobial ß-defensin: Regulation of Wolffian duct morphogenesis.

The Wolffian duct (WD) undergoes morphological changes induced by androgens to form the epididymis, which is an organ essential for sperm maturation. Androgen action in WD epithelium involves paracrine factors of mesenchymal origin that function by still poorly understood mechanisms. Here we studied the antimicrobial ß-defensin SPAG11C as a new player in duct morphogenesis, localized prenatally in the WD mesenchyme. Organotypic culture of rat WDs and tissues from Androgen Receptor (AR) knockout mice (ARKO) were used. Our results show that androgen/AR signaling differentially regulated SPAG11C expression at mRNA and protein levels in the developing WD. WDs incubated with recombinant human SPAG11C were shorter and less coiled as a result of reduced epithelial cell proliferation, but not increased apoptosis. Our results suggested ß-defensin SPAG11C as an androgen-target required for WD morphogenesis. This highlights the multifunctional repertoire of the ß-defensin protein family and their potential contribution to the in utero environment that determines male reproductive success.

Conservative treatment and follow-up of vaginal Gartner's duct cysts: a case series.

BACKGROUND: In women, during embryologic development, the paired Müllerian (paramesonephric) ducts fuse distally and develop into the uterus, cervix, and upper vagina. If the Wolffian ducts persist in vestigial form, they can lead to Gartner's cysts, mainly located in the right wall of the vagina. This is one of the few studies of Gartner's cysts with a series of consecutive cases over a long period of time who were exclusively subject to clinical observation. Although Gartner's cysts are found in approximately 0.1 to 0.2% of women, controversy exists regarding the course of action to be taken. CASE PRESENTATION: We describe the cases of four women who were 38-years old, 53-years old, 37-years old, and 49-years old at their first appointment and who were of mixed ethnicity, mixed ethnicity, black, and mixed ethnicity respectively. The follow-up of these patients ranged from 2 to 17 years. In these four cases the location of the cysts was the right wall of the vagina. Transvaginal ultrasound was the test of choice for diagnostic confirmation. In the cases presented in this study, the women were asymptomatic and chose to be observed clinically. CONCLUSIONS: This is the first study reporting long-term clinical observation of these lesions. This study shows that conservative treatment can be a safe option for asymptomatic patients with vaginal Gartner's duct cysts.

Bilateral isolated Epididymal Agenesis in a 32 year old man.

Epididymal agenesis is defined as the absence of the epididymis totally or segmentally, unilateral or bilateral, which is secondary to the Wolffian duct malformation (1). Rete testis, epididymis, vas deferens and seminal vesicle are believed to develop from Wolffian ducts.

Bilateral isolated Epididymal Agenesis in a 32 year old man

Epididymal agenesis is defined as the absence of the epididymis totally or segmentally, unilateral or bilateral, which is secondary to the Wolffian duct malformation (1). Rete testis, epididymis, vas deferens and seminal vesicle are believed to develop from Wolffian ducts.

Dynamic changes in the spatio-temporal expression of the ß-defensin SPAG11C in the developing rat epididymis and its regulation by androgens.

Herein, we characterized the spatio-temporal expression, cellular distribution and regulation by androgens of the ß-defensin SPAG11C, the rat ortholog of the human SPAG11B isoform C, in the developing epididymis by using RT-PCR, in situ hybridization and immunohistochemistry. We observed that Spag11c mRNA was ubiquitously expressed in rat fetuses, but preferentially detected in male reproductive tissues at adulthood. SPAG11C (mRNA and protein) was prenatally mainly detected in the mesenchyme of the Wolffian duct, switching gradually after birth to a predominant localization in the epididymis epithelium during postnatal development. In the adult epididymis, smooth muscle and interstitial cells were also identified as sources of SPAG11C. Furthermore, SPAG11C was differentially immunolocalized on spermatozoa surface during their transit from testis throughout caput and cauda epididymis. Developmental and surgical castration studies suggested that androgens contribute to the epididymal cell type- and region-specific modulation of SPAG11C mRNA levels and immunolocalization. Together our findings provide novel insights into the potential role of ß-defensins in the epididymis.

[Müllerian anomalies. Obstructed hemivagina and ipsilateral renal anomaly syndrome (OHVIRA)]. / Malformaciones müllerianas. Síndrome de hemivagina obstruida y anomalía renal ipsilateral (OHVIRA).

Müllerian duct anomalies are a group of uncommon and underdiagnosed entities, which cause specific symptoms in adolescent females and may be associated with infertility as well as adverse pregnancy outcomes. These malformations occur as a result of an arrest or abnormal development of the Müllerian ducts in different stages of the female reproductive tract during gestation. Obstructed hemivagina and ipsilateral renal anomaly syndrome (OHVIRA), formerly known as the Herlyn-Werner-Wunderlich syndrome, is a rare entity characterized by the presence of a uterus didelphys with an obstructed hemivagina cause by a vaginal septum and the association of a renal anomaly (most commonly renal agenesis) ipsilateral to the obstruction. This syndrome may remain undiagnosed during childhood and usually becomes symptomatic after menarche, causing obstructive symptoms. Occasionally it may be identified after the evaluation of a patient with infertility or recurrent pregnancy loss. The clinical diagnosis is very challenging and requires imaging studies in which ultrasound and MRI play an essential role in the diagnosis, classification and treatment plan. Opportune diagnosis and treatment achieve complete improvement of symptoms, adequate reproductive prognosis and avoid major complications such as endometriosis, pelvic adhesions and infertility. The purpose of this review is to demonstrate the pathophysiology, clinical manifestations, diagnostic methods and treatment of the obstructed hemivagina and ipsilateral renal anomaly syndrome.

Las malformaciones de los conductos de Müller son un grupo de entidades raras y poco diagnosticadas que ocasionan síntomas inespecíficos en adolescentes y pueden acompañarse de problemas de infertilidad y RESULTADOS obstétricos adversos. Estas malformaciones ocurren durante la gestación como consecuencia del desarrollo anormal de los conductos de Müller en diferentes etapas del proceso de formación del aparato reproductor femenino. El síndrome de hemivagina obstruida y anomalía renal ipsilateral, antes conocido como el síndrome de Herlyn-Werner-Wünderlich, es un padecimiento poco común, caracterizado por útero didelfo con una hemivagina obstruida por un tabique vaginal, y la asociación de una anomalía renal (agenesia renal principalmente) ipsilateral a la obstrucción. Este síndrome rara vez se identifica durante la niñez y se vuelve sintomático posterior a la menarquia, ocasionado por los síntomas obstructivos. A veces se identifica posterior a la evaluación de una paciente con problemas de infertilidad o pérdidas gestacionales recurrentes. El diagnóstico clínico es difícil, por eso se requieren estudios de imagen en los que el ultrasonido y la resonancia magnética desempeñan un papel decisivo para el diagnóstico, clasificación y plan terapéutico. El diagnóstico y tratamiento oportunos logran la desaparición de los síntomas, con pronóstico reproductivo adecuado, y se evitan las principales complicaciones: endometriosis, adherencias pélvicas e infertilidad. OBJETIVO: mostrar la fisiopatología, las manifestaciones clínicas, los métodos diagnósticos y terapéuticos del síndrome de hemivagina obstruida y anomalía renal ipsilateral.

The developmental nephrome: systems biology in the developing kidney.

PURPOSE OF REVIEW: A set of important genes and signaling pathways involved in kidney development is emerging from analyses of mutant mice, in-vitro models, and global gene expression patterns. Conversion of data into dynamic models or networks through the synthesis of information at multiple levels is crucial for a better understanding of kidney development. RECENT FINDINGS: Genetic and in-vitro evidence is beginning to provide a limited sense of the network topology in stages of kidney development. Intriguing data from other fields suggest how, with the aid of large-scale gene expression studies, these stages might be represented as dynamic attractor states. It is also suggested how branching morphogenesis of the epithelial ureteric bud may be sustained by an autocatalytic set of proteins whose interactions lead to repeated rounds of tip and stalk generation. Accumulating data in lower organisms suggest network topologies may be quite flexible, and the implications of these results for varieties of tubulogenesis and renal regeneration after acute injury are discussed. SUMMARY: Currently it may be feasible to build tentative dynamic multistage models of nephrogenesis that facilitate experimental thinking. As data accumulate, it may become possible to test their predictive value.

Onset of sex differentiation: dialog between genes and cells.

During the late 1940s, Alfred Jost demonstrated that mammalian sex differentiation begins in fetal testis, producing two factors necessary for the establishment of phenotypic males. Castrated embryos prior to testis differentiation led to phenotypic female differentiation. Jost proposed the existence of a testis-determining factor (TDF), elucidated in 1990 and named SRY for humans and Sry for mice. Thereafter, an increasing list of genes expressed in the genital ridges of mouse embryos at the onset of gonad differentiation has appeared. To date, it is clear that complete understanding of the mechanisms underlying gonadal sex differentiation in mammals requires identification of key cell lineages in which gonadal-specific genes are expressed. Here, a correlation between known gene expression and gonadal morphologic changes is attempted.

Embryology and endocrinology of genital development.

In the human male fetus, testes develop by the 7th week and begin to secrete two hormones: anti-müllerian hormone (AMH) induces the regression of müllerian ducts, the anlagen of the uterus, fallopian tubes and upper vagina, upon binding to a specific membrane receptor, whereas testosterone induces the differentiation of the wolffian ducts into the epididymes, vasa deferentia and seminal vesicles. In some target tissues, testosterone is converted to dihydrotestosterone, which is responsible for masculinization of the urogenital sinus and external genitalia. Both androgens act upon binding to the same nuclear receptor. In the absence of AMH and androgen action, or example in the female or in abnormal male differentiation, the internal and external genital primordia differentiate following the female pathway, even in the absence of ovaries. In males, an impaired function of the AMH-dependent pathway results in the persistent müllerian duct syndrome, a disorder characterized by the presence of uterus and fallopian tubes in otherwise normally virilized boys. Several mutations found in the AMH and AMH-receptor genes explain the pathophysiology of this syndrome.

Spermatozoon maturation in vertebrates with internal fertilization.

Sperm maturation occurs in the mammalian spermatozoon during its passage through the epididymis. Maturation comprises a series of morpho-physiological changes, which includes the acquisition of the fertilizing capacity in the gamete. This maturative process has been particularly studied in mammals, but different data reveal that birds, reptiles and some kind of fish have a similar characteristic. Anatomical and histological analyses of mammalian epididymis and of Wolffian ducts of some birds and reptiles show the predominance of a secretory cell system. Proteins secreted by the male ducts seem to be an important factor involved in the acquisition of motility, as well as in the changes in the molecular organization of the plasma membrane. Changes occurring in the plasma membrane of the mammalian spermatozoon are related to the acquisition of foreign proteins (of epididymal origin). Some of these membrane changes seem to be connected with the capacitation phenomena and also with gamete interaction during fertilization. The use of antibodies against Wolffian duct proteins has shown that spermatozoa birds and reptiles also acquire proteins during their passage through the male duct. Nevertheless, in birds, and probably in reptiles, capacitation is not a pre-requisite for fertilization and some testicular spermatozoa are able to fertilize the egg. Then, what is the real significance of the membrane maturative changes in these subtherian vertebrates? Proteins acquired during maturation in such species must have different functions from those in mammals, to support spermatozoon survival and/or transport in the female tract, where spermatozoa are stored for a long time. Surface changes in mammals would possibly have similar roles when the gametes are in the female tract.

Spermatozoon maturation in vertebrates with internal fertilization

La maduración del espermatozoide de los mamíferos ocurre durante su tránsito a través del epidídimo. La maduración comprende una serie de cambios morfológicos y fisiológicos que comprenden la adquisición de la capacidad fertilizante de la gameta. Este proceso de maduración ha sido estudiado principalmente en los mamíferos, pero existen datos que revelan que los pájaros, reptiles y ciertos tipos de peces poseen características similares. El análisis anatómico e histológico del epidídimo de los mamíferos y de los conductos de Wolff de algunos pájaros y reptiles muestra el predominio de un sistema de células secretoras. Las proteínas secretadas por los conductos de los machos parece ser un factor importante en la adquisición de la motilidad del espermatozoide, así como en los cambios que ocurren en la organización molecular de la membrana plasmática. Los cambios que ocurren en la membrana plasmática de los espermatozoides de mamíferos se relacionan con la adquisición de proteínas foráneas (de origen epididimario). Algunos de estos cambios de la membrana parecen conectarse con el fenómeno de capacitación y también con la interacción de las gametas durante la fertilización. El uso de anticuerpos contra las proteínas del conducto de Wolff ha mostrado que los espermatozoides de los pájaros y reptiles también incorporan proteínas durante su pasaje a través de este conducto. Sin embargo, en los pájaros y también en los reptiles, la capacitación no es un prerequisito para fertilizar y algunos son capaces de fertilizar con espermatozoides del testículo. Por consiguiente se plantea la cuestión acerca del real significado de los cambios de maduración en estos vertebrados. Las proteínas adquiridas durante la maduración en tales especies tendrían funciones diferentes a las de los mamíferos, probablemente como apoyo para la sobrevivencia de los espermatozoides durante el transporte en el tracto reproductor femenino, donde as veces son depositados por largo tiempo. Posiblemente un rol similar podrían tener los cambios de superficie en las gametas de los mamíferos cuando están en el tracto reproductor femenino (AU)