Anti-Müllerian hormone and its receptors

The potential role of microRNAs in regulating gonadal sex differentiation in the chicken embryo

Differential gene expression regulates tissue morphogenesis. The embryonic gonad is a good example, where the developmental decision to become an ovary or testis is governed by female- or male-specific gene expression. A number of genes have now been identified that control gonadal sex differentiation. However, the potential role of microRNAs (miRNAs) in ovarian and testicular pathways is unknown. In this review, we summarise our current understanding of gonadal differentiation and the possible involvement of miRNAs, using the chicken embryo as a model system. Chickens and other birds have a ZZ/ZW sex chromosome system, in which the female, ZW, is the heterogametic sex, and the male, ZZ, is homogametic (opposite to mammals). The Z-linked DMRT1 gene is thought to direct testis differentiation during embryonic life via a dosage-based mechanism. The conserved SOX9 gene is also likely to play a key role in testis formation. No master ovary determinant has yet been defined, but the autosomal FOXL2 and Aromatase genes are considered central. No miRNAs have been definitively shown to play a role in embryonic gonadal development in chickens or any other vertebrate species. Using next generation sequencing, we carried out an expression-based screen for miRNAs expressed in embryonic chicken gonads at the time of sexual differentiation. A number of miRNAs were identified, including several that showed sexually dimorphic expression. We validated a subset of miRNAs by qRT-PCR, and prediction algorithms were used to identify potential targets. We discuss the possible roles for these miRNAs in gonadal development and how these roles might be tested in the avian model.

Promiscuity and specificity in BMP receptor activation

Bone Morphogenetic Proteins (BMPs), together with Transforming Growth Factor (TGF)-β and Activins/Inhibins constitute the TGF-β superfamily of ligands. This superfamily is formed by more than 30 structurally related secreted proteins. Since TGF-β members act as morphogens, either a strict relation between a particular ligand to a distinct cellular receptor and/or temporospatial expression patterns of ligands and receptors is expected. Instead, only a limited number of receptors exist implicating promiscuous interactions of ligands and receptors. Furthermore, in complex tissues a multitude of different ligands can be found, which signal via overlapping subsets of receptors. This raises the intriguing question how concerted interactions of different ligands and receptors generate highly specific cellular signals, which are required during development and tissue homeostasis.

A Y-linked anti-Müllerian hormone duplication takes over a critical role in sex determination

Gonadal sex determination in vertebrates generally follows a sequence of genetically programmed events. In what is seemingly becoming a pattern, all confirmed or current candidate "master" sex-determining genes reported in this group, e.g., SRY in eutherian mammals, DMY/dmrt1bY in medaka, DM-W in the African clawed frog, and DMRT1 in chicken encode transcription factors. In contrast, here we show that a male-specific, duplicated copy of the anti-Müllerian hormone (amh) is implicated in testicular development of the teleost fish Patagonian pejerrey (Odontesthes hatcheri). The gene, termed amhy because it is found in a single metacentric/submetacentric chromosome of XY individuals, is expressed much earlier than the autosomal amh (6 d after fertilization vs. 12 wk after fertilization) and is localized to presumptive Sertoli cells of XY males during testicular differentiation. Moreover, amhy knockdown in XY embryos resulted in the up-regulation of foxl2 and cyp19a1a mRNAs and the development of ovaries. These results are evidence of a functional amh duplication in vertebrates and suggest that amhy may be the master sex-determining gene in this species. If confirmed, this would be a unique instance of a hormone-related gene, a member of the TGF-β superfamily, in such a role.

Serum anti-Müllerian hormone, inhibin B, and total inhibin levels in women with hypothalamic amenorrhea and anorexia nervosa

OBJECTIVE

To evaluate whether neuroendocrine forms of secondary amenorrhea (hypothalamic nervosa (HA) and anorexia nervosa (AN)) affect serum anti-Müllerian hormone (AMH), inhibin B, and total inhibin levels.

METHODS

Amenorrheic women (n = 82) (aged between 16 and 35 years old) according to diagnosed with neuroendocrine forms of amenorrhea: HA (n = 64), AN (n = 18), and healthy women (n = 41) (control group) were enrolled. Serum AMH, inhibin B, and total inhibin levels were measured by specific ELISA.

RESULTS

No statistically significant difference of AMH serum levels between women with HA, AN, and control group was observed. Serum inhibin B and total inhibin levels in women with HA (p < 0.0001), AN (p < 0.05) resulted significantly lower than in control healthy women.

CONCLUSION

The present data showed that neuroendocrine forms of amenorrhea are associated with an impaired inhibin secretion while not AMH. These data indirectly support that AMH is an excellent marker of ovarian reserve and its secretion is not influenced by the hypothalamic-ovarian axis activity.

[The Sertoli cell]

The Sertoli cell is essential for the formation and functioning of the testis. This is the first cell to differentiate into the initially bipotential genital ridge and is the only somatic cell present in seminiferous tubules. Maturation involves the loss of proliferative capacity, formation of intercellular tight junctions and the appearance of some specific markers. We can consider schematically two distinct roles associated with different features: a process of sexual differentiation with testicular formation and a role in spermatogenesis allowing the germ cells progression into sperm through close contact in the seminiferous tubules. These events, separated in time, are in fact intimately linked.

Normal and abnormal epithelial differentiation in the female reproductive tract

In mammals, the female reproductive tract (FRT) develops from a pair of paramesonephric or Müllerian ducts (MDs), which arise from coelomic epithelial cells of mesodermal origin. During development, the MDs undergo a dynamic morphogenetic transformation from simple tubes consisting of homogeneous epithelium and surrounding mesenchyme into several distinct organs namely the oviduct, uterus, cervix and vagina. Following the formation of anatomically distinctive organs, the uniform MD epithelium (MDE) differentiates into diverse epithelial cell types with unique morphology and functions in each organ. Classic tissue recombination studies, in which the epithelium and mesenchyme isolated from the newborn mouse FRT were recombined, have established that the organ specific epithelial cell fate of MDE is dictated by the underlying mesenchyme. The tissue recombination studies have also demonstrated that there is a narrow developmental window for the epithelial cell fate determination in MD-derived organs. Accordingly, the developmental plasticity of epithelial cells is mostly lost in mature FRT. If the signaling that controls epithelial differentiation is disrupted at the critical developmental stage, the cell fate of MD-derived epithelial tissues will be permanently altered and can result in epithelial lesions in adult life. A disruption of signaling that maintains epithelial cell fate can also cause epithelial lesions in the FRT. In this review, the pathogenesis of cervical/vaginal adenoses and uterine squamous metaplasia is discussed as examples of such incidences.

WT1 mutation as a cause of 46 XY DSD and Wilm's tumour: a case report and literature review

AIM

The Wilms' Tumour gene is thought to have tumour suppressor activity and to play an important role in nephrogenesis, genitourinary development, haematopoiesis and sex determination. WT1 mutations will impair gonadal and urinary tract development and have been demonstrated to cause syndromes of WAGR, Denys-Drash and Fraiser.

METHODS

To elucidate the role of constitutional mutations of WT1, in the expression of the different clinical feature, we describe a 14-year-9-month nonmosaic XY sex-reversed woman with pure gonadal dysgenesis (46, XY karyotype, completely female external genitalia, normal Mullerian ducts, absence of Wolffian ducts, streak gonads) who had right kidney removed at 7 months of age because of Wilms' tumour and was diagnosed as secondary thrombocytopenia (Plt 60-80 × 10(9) /L) since she was 4 years old. We sequenced the genomic DNA of all the 10 exons of the WT1 in which mutations may occur in proposita.

RESULTS

A new de novo insertion mutation in the first exon was found. A 'GCCGCCTCACTCC' is inserted between codon 138 and 139, resulting in the creation of a stop codon and a truncated protein.

CONCLUSION

The present data provide further evidence to support the role of WT1 in diverse cellular functions.

Secretion profiles from in vitro cultured follicles, isolated from fresh prepubertal and adult mouse ovaries or frozen-thawed prepubertal mouse ovaries

In vitro folliculogenesis could be a new technology to produce mature oocytes from immature follicles that have been isolated from cryopreserved or fresh ovarian tissue. This technique could also be a tool for evaluation of oocyte quality and/or for determination of follicular parameters during follicular growth. Our objective was to characterize in mice the secretion profiles of follicles that had been isolated mechanically during in vitro follicular growth and in relation to the growth curve. Early preantral follicles from fresh prepubertal and adult mouse ovaries or frozen-thawed prepubertal mouse ovaries were cultured individually in microdrops under oil for 12 days. Each day, two perpendicular diameters of the follicles were measured. From day-3 to day-12 of culture, culture medium was collected and preserved for determination of inhibin B, anti-Müllerian hormone (AMH) and estradiol levels. At the end of the culture, after maturation, the status of the oocyte was evaluated. Follicular growth and their individual hormone production did not always correlate. Inhibin B was never secreted from follicles of less than 200 μm diameter, whether the follicles were examined when fresh or after freezing-thawing. Estradiol secretion was never observed in frozen-thawed follicles. AMH was mainly secreted between day-3 and day-9. Despite similar morphological aspects at the start of culture, follicles selected for in vitro folliculogenesis were found to be heterogeneous and differed in their ability to grow and to produce hormones, even if they had similar growth curves. Follicles from frozen-thawed ovaries developed slowly and produced fewer hormones than freshly collected follicles.

Altered differentiation and clustering of Sertoli cells in transgenic mice showing a Sertoli cell specific knockout of the connexin 43 gene

Histological analysis revealed that Sertoli cell specific knockout of the predominant testicular gap junction protein connexin 43 results in a spermatogenic arrest at the level of spermatogonia or Sertoli cell-only syndrome, intratubular cell clusters and still proliferating adult Sertoli cells, implying an important role for connexin 43 in the Sertoli and germ cell development. This study aimed to determine the (1) Sertoli cell maturation state, (2) time of occurrence and (3) composition, differentiation and fate of clustered cells in knockout mice. Using immunohistochemistry connexin 43 deficient Sertoli cells showed an accurate start of the mature markers androgen receptor and GATA-1 during puberty and a vimentin expression from neonatal to adult. Expression of anti-Muellerian hormone, as a marker of Sertoli cell immaturity, was finally down-regulated during puberty, but its disappearance was delayed. This observed extended anti-Müllerian hormone synthesis during puberty was confirmed by western blot and Real-Time PCR and suggests a partial alteration in the Sertoli cell differentiation program. Additionally, Sertoli cells of adult knockouts showed a permanent and uniform expression of GATA-1 at protein and mRNA level, maybe caused by the lack of maturing germ cells and missing negative feedback signals. At ultrastructural level, basally located adult Sertoli cells obtained their mature appearance, demonstrated by the tripartite nucleolus as a typical feature of differentiated Sertoli cells. Intratubular clustered cells were mainly formed by abnormal Sertoli cells and single attached apoptotic germ cells, verified by immunohistochemistry, TUNEL staining and transmission electron microscopy. Clusters first appeared during puberty and became more numerous in adulthood with increasing cell numbers per cluster suggesting an age-related process. In conclusion, adult connexin 43 deficient Sertoli cells seem to proliferate while maintaining expression of mature markers and their adult morphology, indicating a unique and abnormal intermediate phenotype with characteristics common to both undifferentiated and differentiated Sertoli cells.

Decrease of anti-Mullerian hormone in genetic spermatogenic failure

The aim of this study was to compare anti-Mullerian hormone (AMH) plasma levels in patients with azoospermia according to the physiopathology. In a prospective clinical study from April 2008 to March 2009 in University Hospital, we measured AMH levels in 49 consecutive patients with azoospermia. AMH plasma levels were correlated with FSH, inhibin B, bioavailable testosterone plasma levels and testicular volume and compared between nonobstructive azoospermia (NOA) and obstructive azoospermia (OA) and within four physiopathological subgroups of NOA: genetic, cryptorchidism, cytotoxic and unexplained. AMH, FSH, inhibin B, bioavailable testosterone plasma levels and testicular volumes were all related to each other. AMH plasma levels were lower in NOA relatively to OA. Lowest values were observed in cases of genetic NOA and on the other hand, the values observed in case of cytotoxic NOA were as high as the values observed in OA. FSH, inhibin B, bioavailable testosterone and testicular volume were not different between genetic and cytotoxic NOA. These results suggest that the decrease in AMH plasma levels is related to the origin of NOA, with low values in genetic NOA and values similar to OA in cytotoxic NOA. Further studies will be useful to understand the fine regulation of AMH production.

Elevated amh gene expression in the brain of male tilapia (Oreochromis niloticus) during testis differentiation

Anti-müllerian hormone (AMH) is expressed in male embryos and represses development of müllerian ducts during testis differentiation in mammals, birds and reptiles. Amh orthologues have been identified in teleosts despite them lacking müllerian ducts. Previously we found sexually dimorphic aromatase activity in tilapia brains before ovarian differentiation. This prompted us to search for further dimorphisms in tilapia brains during sex differentiation and see whether amh is expressed. We cloned the tilapia amh gene and found that it contains 7 exons but no spliced forms. The putative protein presents highest homologies with Amh proteins of pejerrey and medaka as compared to other Perciformes. We analysed amh expression in adult tissues and found elevated levels in testes, ovary and brain. Amh expression was dimorphic with higher levels in XY male brains at 10-15 dpf, when the gonads were still undifferentiated and gonadal amh was not dimorphic. Male brains had 2.7-fold higher amh expression than gonads. Thereafter, amh levels decreased in the brain while they were up-regulated in differentiating testes. Our study indicates that amh is transcribed in male brains already at 10 dpf, suggesting that sexual differentiation may be occurring earlier in tilapia brain than in gonads.

Anomalies postnatales du développement de la spermatogenèse associées aux troubles de la migration testiculaire

La cryptorchidie, testicule non descendu dans sa position normale intrascrotale, est l’une des anomalies congénitales les plus fréquentes du système génital masculin. Le mécanisme de cette migration est un processus complexe encore mal connu. Plusieurs hypothèses étiologiques ont été avancées pour tenter d’expliquer la survenue de la cryptorchidie. L’existence d’une anomalie de la descente testiculaire, même traitée dans l’enfance, est un facteur de risque de cancer du testicule. Mais elle peut aussi se traduire à l’âge adulte par des anomalies des paramètres spermatiques et une atteinte de la fertilité. Dans la présente revue sont rassemblées les données concernant les anomalies du développement postnatal de la spermatogenèse observées en cas de troubles isolés de la migration du testicule et leurs conséquences à l’âge adulte sur les paramètres de la fertilité.

Cytokines and chemokines in testicular inflammation: A brief review

A wide spectrum of data in the literature shows the relevance of cytokines as paracrine regulators of spermatogenesis and steroidogenesis in the normal testis. In this brief review, we highlight the relevance of cytokines in the testis during inflammation. This phenomenon involves complex and multiple interactions among immune and germ cells generally resulting in the alteration of spermatogenesis. The complexity of these cell interactions is multiplied because Sertoli and Leydig cells are also producers of pro- and anti-inflammatory cytokines and chemokines. Also, cytokines are pleiotropic and they exert opposite and/or redundant effects in different conditions. However, in spite of this bidirectional immunoregulatory function of cytokines, the mass of the data, reported from experiments of acute testicular inflammation, shows upregulation of interleukin (IL)-1beta, IL-1alpha, IL-6, and tumor necrosis factor alpha (TNF-alpha), which induce adverse effects on germ cells. In autoimmune orchitis, a chronic testicular inflammation, chemokines such as CCL2, CCL3, and CCL4 induce attraction and extravasation of immune cells within the testicular interstitium. These cells alter the normal immunosuppressor microenvironment principally through the secretion of proinflammatory cytokines, interferon-gamma initially, and IL-6 and TNF-alpha thereafter. Germ cells expressing TNFR1, IL-6R, and Fas increase in number and undergo apoptosis, through the TNF-alpha/TNFR1, IL-6/IL-6R, and Fas/Fas L systems. The knowledge of immune-germ and somatic testicular cell interactions will contribute to the understanding of the mechanisms by which chronic inflammatory conditions of the testis can disrupt the process of spermatogenesis.

Expression of activated PIK3CA in ovarian surface epithelium results in hyperplasia but not tumor formation

Background

The Phosphatidylinositol 3′-kinase is a key regulator in various cancer-associated signal transduction pathways. Genetic alterations of its catalytic subunit alpha, PIK3CA, have been identified in ovarian cancer. Our in vivo data suggests that PIK3CA activation is one of the early genetic events in ovarian cancer. However, its role in malignant transformation of ovarian surface epithelium (OSE) is largely unclear.

Methodology/Principal Findings

Using the Müllerian inhibiting substance type II receptor (MISIIR) promoter, we generated transgenic mice that expressed activated PIK3CA in the Müllerian epithelium. Overexpression of PIK3CA in OSE induced remarkable hyperplasia, but was not able to malignantly transform OSE in vivo. The consistent result was also observed in primary cultured OSEs. Although enforced expression of PIK3CA could not induce OSE anchorage-independent growth, it significantly increased anchorage-independent growth of OSE transformed by mutant K-ras.

Conclusions/Significance

While PIK3CA activation may not be able to initiate OSE transformation, we conclude that activation of PIK3CA may be an important molecular event contributing to the maintenance of OSE transformation initiated by oncogenes such as K-ras.

The cell of origin of ovarian epithelial tumours

Although it is widely believed that ovarian epithelial tumours arise in the coelomic epithelium that covers the ovarian surface, it has been suggested that they could instead arise from tissues that are embryologically derived from the Müllerian ducts. This article revisits this debate by discussing recent epidemiological and molecular biological findings as well as evidence based on histopathological observations of surgical specimens from individuals with familial ovarian cancer predisposition. Morphological, embryological, and molecular biological characteristics of ovarian epithelial tumours that must be accounted for in formulating a theory about their cell of origin are reviewed, followed by comments about the ability of these two hypotheses to account for each of these characteristics. An argument is made that primary ovarian epithelial tumours, fallopian tube carcinomas, and primary peritoneal carcinomas are all Müllerian in nature and could therefore be regarded as a single disease entity. Although a substantial proportion of cancers currently regarded as of primary ovarian origin arise in the fimbriated end of the fallopian tube, this site cannot account for all of these tumours, some of which are most likely derived from components of the secondary Müllerian system.

Factors controlling testis descent

Descent of the testis from an intra-abdominal site in foetal life to an extracorporeal location after birth is a mandatory developmental process to ensure that the mature testis promotes normal spermatogenesis. The two phases of transabdominal and inguinoscrotal descent occur approximately during the first and last thirds of gestation respectively. Key anatomical events to release the testis from its urogenital ridge location and to guide the free gonad into the scrotum are the degeneration of the cranio-suspensory ligament and a thickening of the gubernaculum. Androgens play a role in both these processes, particularly with respect to enabling the testis to traverse the inguinal canal in the final phase of descent. Experiments in animals suggest that androgens mediate this effect via the release of calcitonin gene-related peptide by the genitofemoral nerve, but direct evidence for such a mechanism is lacking in humans. The transabdominal phase of descent is under the control of insulin-like 3 (INSL3), a product of the Leydig cells. Definitive evidence of its role in rodent testis descent is illustrated by the phenotype of bilateral cryptorchidism in Insl3-/- null mice. Circulating levels of INSL3 are higher in boys at puberty, are undetectable in girls and are lower in boys with undescended testes. A minority also have a mutation either in the INSL3 gene or affecting its receptor gene, relaxin/insulin-like family peptide receptor 2 (LGRF8). Other factors that may play a role in testis descent include the anti-Mullerian hormone and members of the HOX gene family. Evidence that the prevalence of undescended testis may be increasing provides a phenotypic readout for the effects of postulated chemicals in the environment interfering in some way with the action of factors that control testis descent. Epidemiological studies point to profound geographical variations in prevalence in countries such as Denmark and Finland. Associations have been found with levels of chemicals labelled as endocrine disruptors being higher in breast milk samples from mothers with cryptorchid boys when compared with controls. The adverse effects of these compounds (e.g. bisphenol A) can be replicated in the offspring of dams exposed during pregnancy. A sensitive marker of an anti-androgen effect of a compound is a reduction in the anogenital distance, an anthropometric measurement that is significantly greater in males compared with females. The observation of an association between the anogenital distance in infant boys and the level of pesticides in the urine of their mothers in late gestation indicates that this has the potential to be a useful surrogate marker of the effects of environmental chemicals on testis descent in human population studies. The rightful place for the testis at birth is in the scrotum in order to provide the temperature differential essential for normal spermatogenesis. Appropriate screening programmes and early surgical intervention are the prerequisites to ensure optimal fertility in adulthood and a considerably lessened risk of testis cancer.

Follicle-stimulating hormone receptor polymorphism and seminal anti-Müllerian hormone in fertile and infertile men

Follicle-stimulating hormone (FSH) is fundamental for Sertoli cell function stimulating spermatogenesis and follicular growth by a specific receptor (FSHR). This work aimed to investigate the occurrence of Asn and Ser FSHR gene variants and its relationship with seminal anti-Müllerian hormone (AMH) among normozoospermic and infertile oligoasthenozoospermic (OAT) males. Eighty-two Caucasian males grouped into normozoospermic healthy controls (n = 30) and infertile OAT males (n = 52). FSHR gene variants were determined by DNA from anti-coagulated blood and underwent polymerase chain reaction (PCR) amplification and electrophoresis in detecting amplification products. AMH in seminal plasma was determined by ELISA. The results showed that the frequency of FSHR gene variants among fertile men was 46.7% Asn/Asn (N680S), 33.3% Asn/Ser, and 20% Ser/Ser, whereas among OAT men were 34.6%, 38.5% and 26.9% respectively with nonsignificant differences. Seminal AMH was significantly higher in fertile than infertile OAT men. There was significant increase in seminal AMH with Asn/Asn variant of FSHR gene than those with Asn/Ser or Ser/Ser. It is concluded that FSH gene variants showed no difference in distribution between fertile or infertile OAT men. However, when correlated with seminal AMH values, there was an increase in Asn/Asn in men with high seminal AMH.

Anti-Mullerian-hormone-dependent regulation of the brain serine-protease inhibitor neuroserpin

The balance between tissue-type plasminogen activator (tPA) and one of its inhibitors, neuroserpin, has crucial roles in the central nervous system, including the control of neuronal migration, neuronal plasticity and neuronal death. In the present study, we demonstrate that the activation of the transforming growth factor-beta (TGFbeta)-related BMPR-IB (also known as BMPR1B and Alk6)- and Smad5-dependent signalling pathways controls neuroserpin transcription. Accordingly, we demonstrate for the first time that anti-Mullerian hormone (AMH), a member of the TGFbeta family, promotes the expression of neuroserpin in cultured neurons but not in astrocytes. The relevance of these findings is confirmed by the presence of both AMH and AMH type-II receptor (AMHR-II) in brain tissues, and is supported by the observation of reduced levels of neuroserpin in the brain of AMHR-II-deficient mice. Interestingly, as previously demonstrated for neuroserpin, AMH protects neurons against N-methyl-D-aspartate (NMDA)-mediated excitotoxicity both in vitro and in vivo. This study demonstrates the existence of an AMH-dependent signalling pathway in the brain leading to an overexpression of the serine-protease inhibitor, neuroserpin, and neuronal survival.

Role of hormones, genes, and environment in human cryptorchidism

Cryptorchidism is the most frequent congenital birth defect in male children (2-4% in full-term male births), and it has the potential to impact the health of the human male. In fact, although it is often considered a mild malformation, it represents the best-characterized risk factor for reduced fertility and testicular cancer. Furthermore, some reports have highlighted a significant increase in the prevalence of cryptorchidism over the last few decades. Etiology of cryptorchidism remains for the most part unknown, and cryptorchidism itself might be considered a complex disease. Major regulators of testicular descent from intraabdominal location into the bottom of the scrotum are the Leydig-cell-derived hormones testosterone and insulin-like factor 3. Research on possible genetic causes of cryptorchidism has increased recently. Abundant animal evidence supports a genetic cause, whereas the genetic contribution to human cryptorchidism is being elucidated only recently. Mutations in the gene for insulin-like factor 3 and its receptor and in the androgen receptor gene have been recognized as causes of cryptorchidism in some cases, but some chromosomal alterations, above all the Klinefelter syndrome, are also frequently involved. Environmental factors acting as endocrine disruptors of testicular descent might also contribute to the etiology of cryptorchidism and its increased incidence in recent years. Furthermore, polymorphisms in different genes have recently been investigated as contributing risk factors for cryptorchidism, alone or by influencing susceptibility to endocrine disruptors. Obviously, the interaction of environmental and genetic factors is fundamental, and many aspects have been clarified only recently.

Expression of anti-Müllerian hormone (AMH) in equine granulosa-cell tumors and in normal equine ovaries

Anti-Müllerian hormone (AMH), also known as Müllerian inhibiting substance (MIS), is expressed by granulosa cells in females of many mammalian species, and circulating AMH concentrations have been used to monitor granulosa-cell tumors (GCT) in women. The objective was to characterize expression of AMH in equine GCT, and in normal equine ovaries, based upon immunohistochemistry (IHC), using a polyclonal primary antibody directed against human AMH. Equine GCT (n=27) and normal equine ovaries (n=10) were examined by IHC. In addition, sera from four mares with GCT were characterized for AMH bioactivity, based upon suppression of Müllerian duct development in the fetal rat. Immunolabeling with alpha-AMH was localized to granulosa cells in equine GCT, as well as within antral follicles in normal ovaries. Expression of AMH first appeared in granulosa cells of small growing follicles and was most intense in small antral follicles; large antral or atretic follicles had reduced immunolabeling. Omission of the primary antibody or incubation of the primary antibody with the corresponding blocking peptide eliminated immunolabeling of granulosa cells in GCT and in normal antral follicles, confirming the specificity of the immunolabel. Sera from mares with GCT had increased AMH bioactivity compared to control sera. In conclusion, AMH was strongly expressed by granulosa cells in equine GCT and in normal antral follicles. Therefore, anti-Müllerian hormone may be a useful biomarker for detection of GCT in the horse.

Transcriptomic analyses reveal novel genes with sexually dimorphic expression in the zebrafish gonad and brain

BACKGROUND

Our knowledge on zebrafish reproduction is very limited. We generated a gonad-derived cDNA microarray from zebrafish and used it to analyze large-scale gene expression profiles in adult gonads and other organs.

METHODOLOGY/PRINCIPAL FINDINGS

We have identified 116638 gonad-derived zebrafish expressed sequence tags (ESTs), 21% of which were isolated in our lab. Following in silico normalization, we constructed a gonad-derived microarray comprising 6370 unique, full-length cDNAs from differentiating and adult gonads. Labeled targets from adult gonad, brain, kidney and 'rest-of-body' from both sexes were hybridized onto the microarray. Our analyses revealed 1366, 881 and 656 differentially expressed transcripts (34.7% novel) that showed highest expression in ovary, testis and both gonads respectively. Hierarchical clustering showed correlation of the two gonadal transcriptomes and their similarities to those of the brains. In addition, we have identified 276 genes showing sexually dimorphic expression both between the brains and between the gonads. By in situ hybridization, we showed that the gonadal transcripts with the strongest array signal intensities were germline-expressed. We found that five members of the GTP-binding septin gene family, from which only one member (septin 4) has previously been implicated in reproduction in mice, were all strongly expressed in the gonads.

CONCLUSIONS/SIGNIFICANCE

We have generated a gonad-derived zebrafish cDNA microarray and demonstrated its usefulness in identifying genes with sexually dimorphic co-expression in both the gonads and the brains. We have also provided the first evidence of large-scale differential gene expression between female and male brains of a teleost. Our microarray would be useful for studying gonad development, differentiation and function not only in zebrafish but also in related teleosts via cross-species hybridizations. Since several genes have been shown to play similar roles in gonadogenesis in zebrafish and other vertebrates, our array may even provide information on genetic disorders affecting gonadal phenotypes and fertility in mammals.

Hormonal and genetic control of testicular descent

Cryptorchidism has the potential to affect the health of the human male. Although it is often considered a mild malformation, it represents the best-characterized risk factor for reduced fertility and testicular cancer. The aetiology of cryptorchidism remains, for the most part, unknown and cryptorchidism itself might be considered a complex disease. This reflects the intricate mechanisms regulating testicular development and descent from intra-abdominal location into the bottom of the scrotum, involving different anatomical and hormonal factors. Major actors of testicular descent are the Leydig cell-derived hormones testosterone and insulin-like factor 3, even if other factors may play a role. Although considerable evidence exists in animals to support a genetic cause, the genetic contribution to human cryptorchidism is only recently being elucidated. Environmental factors might also contribute to the aetiology of cryptorchidism and its increased incidence in recent years. Mutations in the gene for insulin-like factor 3 and its receptor and in the androgen receptor gene explain a minority of cases of cryptorchidism, but research on genetic polymorphisms that may also influence susceptibility to endocrine disruptors is shedding light on this field.

Predictors of ovarian response: progress towards individualized treatment in ovulation induction and ovarian stimulation

Ovarian stimulation is applied in the clinic to restore mono-ovulatory cycles in anovulatory women (ovulation induction) or to induce the development of multiple dominant follicles for assisted reproduction. Ovarian response is the endocrine and follicular reaction of the ovaries to stimulation. Achieving an appropriate ovarian response to anti-estrogens or exogenous gonadotrophins is central to ovulation induction and ovarian stimulation protocols. However, achieving an adequate response, without cycle cancellation or adverse events related to under- or over-stimulation, is complicated by high intra- and inter-individual variability. To predict each patient's ovarian response to medication for ovarian stimulation and to individualize the starting dose of exogenous gonadotrophin or the need for exogenous luteinizing hormone, various clinical, endocrine, ovarian ultrasonographic and genetic characteristics have been explored. Some of these features have been incorporated into prediction models. In this review, the methodology behind predictive factors and prediction models and their potential clinical applicability across ovulation induction and ovarian stimulation are explored.

Müllerian inhibiting substance type II receptor (MISIIR): a novel, tissue-specific target expressed by gynecologic cancers

OBJECTIVE

Müllerian inhibiting substance type II receptor (MISIIR) is expressed by ovarian, breast, and prostate cancers [Masiakos PT, et al. Human ovarian cancer, cell lines, and primary ascites cells express the human Mullerian inhibiting substance (MIS) Type II Receptor, bind, and are responsive to MIS. Clin Cancer Res 1999;5:3488-99; Hoshiya Y, et al. Mullerian inhibiting substance promotes interferon {gamma}-induced gene expression and apoptosis in breast cancer cells. J Biol Chem 2003;278:51703-12; Hoshiya Y, et al. Mullerian inhibiting substance induces NFkB signaling in breast and prostate cancer cells. Mol. Cell. Endocrinol. 2003;211:43-9. [1-3]]. We investigated the expression patterns of MISIIR in benign and malignant gynecologic tissues and benign non-gynecologic tissues to better assess the relevance of MISIIR as a target for new therapeutic and diagnostic approaches to gynecologic cancers. Secondarily, we examined the impact of MISIIR expression on overall survival (OS) and disease-free survival (DFS) in a cohort of epithelial ovarian cancers (EOC).

METHODS

Reverse-transcription polymerase chain reaction (RT-PCR), immunoblotting, and immunohistochemistry (IHC) were used to determine MISIIR expression. EOC cell lines (10), primary EOCs (12), and tissue microarrays (TMAs) containing benign gynecologic (179) and non-gynecologic tissues (25), EOC (182), endometrial carcinomas (109), uterine sarcomas (98), and ovarian dysgerminomas (22) were examined for MISIIR expression. Clinical data were collected for a cohort of 182 EOCs.

RESULTS

Ninety-two percent of primary EOCs and 44% of EOC cell lines expressed MISIIR mRNA. We observed moderate or strong MISIIR expression via IHC in the majority of gynecologic cancers: EOC 69% (125/182), ovarian dysgerminomas 77% (17/22), endometrial cancers 75% (82/109), uterine malignant mixed Müllerian tumors (MMMT) 59% (30/51), uterine leiomyosarcomas (LMS) 52% (15/29), and endometrial stromal sarcomas (ESS) 22% (4/18). Over 74% of normal non-gynecologic tissues did not express MISIIR. There was a significant correlation between MISIIR expression and improved OS (p=0.025, Chi square).

CONCLUSIONS

In the largest study to date, we report that MISIIR is highly expressed by a wide variety of gynecologic cancers, including cancers currently without effective systemic therapies. Low levels of expression in select non-gynecologic tissues coupled with high expression in gynecologic malignancies make MISIIR an attractive target for novel therapeutics and tumor-directed imaging in the management of gynecologic cancers. Further investigation into the impact of MISIIR expression and OS is also warranted.

Gene expression patterns during adaptation of a helminth parasite to different environmental niches

BACKGROUND

Schistosome bloodflukes are complex trematodes responsible for 200 million cases of schistosomiasis worldwide. Their life cycle is characterized by a series of remarkable morphological and biochemical transitions between an invertebrate host, an aquatic environment, and a mammalian host. We report a global transcriptional analysis of how this parasite alters gene regulation to adapt to three distinct environments.

RESULTS

Utilizing a genomic microarray made of 12,000 45-50-mer oligonucleotides based on expressed sequence tags, three different developmental stages of the schistosome parasite were analyzed by pair-wise comparisons of transcript hybridization signals. This analysis resulted in the identification of 1,154 developmentally enriched transcripts.

CONCLUSION

This study expands the repertoire of schistosome genes analyzed for stage-specific expression to over 70% of the predicted genome. Among the new associations identified are the roles of robust protein synthesis and programmed cell death in development of cercariae in the sporocyst stages, the relative paucity of cercarial gene expression outside of energy production, and the remarkable diversity of adult gene expression programs that reflect adaptation to the host bloodstream and an average lifespan that may approach 10 years.

Changes in serum anti-mullerian hormone level during low-dose recombinant follicular-stimulating hormone therapy for anovulation in polycystic ovary syndrome

CONTEXT

We previously hypothesized that the excess of anti-müllerian hormone (AMH) at the level of selectable follicles could be involved in the follicular arrest of polycystic ovary syndrome (PCOS), mainly through inhibition of FSH effect on aromatase expression.

OBJECTIVE

In this study, we investigated whether a decrease in the serum AMH level was concomitant to the appearance of a dominant follicle induced by administration of mild amounts of exogenous FSH in women with PCOS.

DESIGN

A total of 30 women with PCOS in whom anovulation was resistant to clomiphene citrate received recombinant FSH using the low-dose step-up protocol during only one cycle. Serum levels of estradiol, AMH, LH, FSH, inhibin B, and ultrasound parameters were assessed twice a week until 3 d after the appearance of one or more dominant follicle(s).

RESULTS

The day of dominance (d 0) was defined by the appearance of at least one follicle more than 10 mm growing 2 mm/d. From d -14 before dominance to d +3, the mean serum AMH level and the 2- to 5-mm follicle number at ultrasound declined steadily, although not significantly by ANOVA. Mean AMH relative values (100% being the value at d 0) declined significantly (P = 0.04), from 125 +/- 32% at d -14 to 105 +/- 15% at d -4. Within the same time lag, the mean FSH relative values increased from 91 +/- 17% to 107 +/- 19% (P = 0.013). In the 87 samples obtained from d -14 to -4, absolute values of AMH were positively and negatively associated with those of LH and FSH, respectively, in an independent manner (P = 0.009 and P = 0.03, respectively). In the 55 samples collected at d 0 and +3, they were negatively correlated to those of estradiol (r = -0.272; P < 0.05).

CONCLUSIONS

These data suggest that in anovulatory women with PCOS, gently increasing the serum FSH level reduces the AMH excess, thus relieving the inhibition from the latter on aromatase expression by selectable follicles and allowing the emergence of a dominant follicle.

Anti-mullerian hormone: clinical relevance in assisted reproductive therapy

Anti-Müllerian Hormone (AMH) is a member of the transforming Growth Factor-B (TGF-B) family synthesized exclusively by the gonads of both sexes. Over the last four years, numerous studies have examined the clinical usefulness of serum AMH levels as a predictor of ovarian response and pregnancy in assisted reproductive technology cycles. Assessment of ovarian reserve in women undergoing assisted reproduction is useful in optimising the treatment protocol. Availability of a reliable measure of ovarian reserve is essential. Currently, serum AMH level seems to be more strongly related to the ovarian reserve and to be a more discriminatory marker of assisted reproductive technology outcome than follicle-stimulating hormone, inhibin B or estradiol, which are more commonly used markers. Our study involving 69 women undergoing a cycle of in vitro fertilisation (IVF) or intracytoplamic sperm injection (ICSI) treatment, confirmed these results. We have shown in this study that AMH is significantly correlated with the number of eggs collected and is of great interest as a negative predictive value for the success of assisted reproductive technology (ART). Further studies are needed to determine AMH cut-off values.

Expression of AMH in female fetal intersex gonads in the bovine

Anti Müllerian Hormone, AMH, is believed to be the main agent in the freemartin syndrome. Supposing an active role of freemartin gonads in AMH secretion, in the present study, we aimed at investigating the presence and the localization of AMH producing cells either in fetal or in adult freemartin gonads. Our finding of positive AMH cells in a 26-week-old freemartin fetus indicates an active role of masculinized freemartin gonads in AMH secretion. However, the positive reaction, limited to few cells grouped in 'nests' in proximity to testis cord-like structures, supports a chimeric origin of such cells, migrated from the male co-twin. No adult freemartin, irrespective from the degree of masculinization, showed any AMH positive cell.

Statistically significant changes of antimüllerian hormone and inhibin levels during the physiologic menstrual cycle in reproductive age women

OBJECTIVE

To define the dynamics of antimüllerian hormone (AMH) and inhibins during the physiologic menstrual cycle.

DESIGN

Longitudinal study.

SETTING

University hospital.

PATIENT(S)

36 young, healthy, normal weight Caucasian women without medication.

INTERVENTION(S)

Normal ovulatory menstrual cycles were evaluated by regular blood sampling taken every other day and periovulatory every day.

MAIN OUTCOME MEASURE(S)

Serum concentrations of AMH, inhibin A and B, follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, estradiol, progesterone, and free testosterone were measured in all blood samples.

RESULT(S)

Median AMH levels are statistically significantly higher in the late follicular compared with ovulation or the early luteal phase. There are statistically significant correlations between both AMH and FSH, and AMH and free testosterone in all cycle phases. Inhibin A increases strongly in the late follicular phase and peaks at day LH + 4. Inhibin B shows a broad midfollicular and a sharp early luteal peak, the difference being statistically significant between day LH + 4 and the earlier time points and between day LH + 2 and day LH. Although there is a negative association between inhibin A or B and the body mass index (BMI), there is no correlation between AMH and the BMI.

CONCLUSION(S)

Levels of AMH show a statistically significant change during the menstrual cycle and may influence the circulating gonadotropin and steroid hormone levels.

The hotei mutation of medaka in the anti-Mullerian hormone receptor causes the dysregulation of germ cell and sexual development

We previously performed mutant screens in the medaka for defects in gonadal development and identified a mutant of interest in this regard, which was designated as hotei (hot). This mutant manifests a number of remarkable phenotypic abnormalities including: (i) excessive proliferation of germ cells that initiates at around the hatching stage regardless of the genetic sex of the fish; (ii) initiation of premature meiosis in phenotypically male hot homozygotes; (iii) one-half of the hot-homozygous XY fish undergo sex reversal, which accompanies the expression of the female-characteristic aromatase gene in the somatic cells of the gonad; and (iv) in phenotypically female homozygotes, follicular development is arrested at an early stage. We have also performed genetic mapping, chromosome walking, and candidate gene sequencing analysis of hot and demonstrate that the underlying mutation occurs in the recently identified medaka anti-Müllerian hormone (Amh) receptor type II (amhrII) gene. Moreover, this gene was found to be responsible for each of the hot phenotypes, as an amhrII transgene rescues these abnormalities. In addition, the amhrII gene is expressed in the somatic cells of the gonads of both sexes. The phenotypes of the hot homozygotes indicate that there are multiple regulatory functions of the AMH/AMHRII signaling system in the development of the gonad, including the sex-dependent regulation of germ cell proliferation and follicular development. These presumably represent the basic roles of Amh, which precede Müllerian duct evolution during phylogeny.

Differential expression of anti-Müllerian hormone (amh) and anti-Müllerian hormone receptor type II (amhrII) in the teleost medaka

In mammals, the anti-Müllerian hormone (Amh) is responsible for the regression of the Müllerian ducts; therefore, Amh is an important factor of male sex differentiation. The amh gene has been cloned in various vertebrates, as well as in several teleost species. To date, all described species show a sexually dimorphic expression of amh during sex differentiation or at least in differentiated juvenile gonads. We have identified the medaka amh ortholog and examined its expression pattern. Medaka amh shows no sexually dimorphic expression pattern. It is expressed in both developing XY male and XX female gonads. In adult testes, amh is expressed in the Sertoli cells and in adult ovaries in granulosa cells surrounding the oocytes, like in mammals. To better understand the function of amh, we cloned the anti-Müllerian hormone receptor type II (amhrII) ortholog and compared its expression pattern with amh, aromatase (cyp19a1), and scp3. During gonad development, amhrII is coexpressed with medaka amh in somatic cells of the gonads and shows no sexually dimorphic expression. Only the expression level of the Amh type II receptor gene was decreased noticeably in adult female gonads. These results suggest that medaka Amh and AmhrII are involved in gonad formation and maintenance in both sexes.

Wilms' tumor protein Wt1 is an activator of the anti-Müllerian hormone receptor gene Amhr2

The Wilms' tumor protein Wt1 plays an essential role in mammalian urogenital development. WT1 mutations in humans lead to a variety of disorders, including Wilms' tumor, a pediatric kidney cancer, as well as Frasier and Denys-Drash syndromes. Phenotypic anomalies in Denys-Drash syndrome include pseudohermaphroditism and sex reversal in extreme cases. We have used cDNA microarray analyses on Wt1 knockout mice to identify Wt1-dependent genes involved in sexual development. The gene most dramatically affected by Wt1 inactivation was Amhr2, encoding the anti-Müllerian hormone (Amh) receptor 2. Amhr2 is an essential factor for the regression of the Müllerian duct in males, and mutations in AMHR2 lead to the persistent Müllerian duct syndrome, a rare form of male pseudohermaphroditism. Here we show that Wt1 and Amhr2 are coexpressed during urogenital development and that the Wt1 protein binds to the promoter region of the Amhr2 gene. Inactivation and overexpression of Wt1 in cell lines was followed by immediate changes of Amhr2 expression. The identification of Amhr2 as a Wt1 target provides new insights into the role of Wt1 in sexual differentiation and indicates, in addition to its function in early gonad development and sex determination, a novel function for Wt1, namely, in Müllerian duct regression.

Growth factors and folliculogenesis in polycystic ovary patients

Ovarian folliculogenesis is regulated by a fine balance between endocrine and intraovarian factors. In this review, we focus on the role of growth factors in physiological folliculogenesis and in polycystic ovaries. Recent evidence shows that the main systems implicated in polycystic ovary folliculogenesis are the growth hormone and insulin-like growth factor system, vascular endothelial growth factor, and the transforming growth factor-β family. Growth hormone and the insulin-like growth factor system could affect follicular development and oocyte maturation if their balance was altered, while vascular endothelial growth factor is implied in follicular dominance by providing an increasing vascular supply. The transforming growth factor-β family is composed of various molecules, which have different roles in cellular proliferation. Finally, a series of different factors seem to be involved in altered polycystic ovary follicular growth.

Development of a Sexually Differentiated Behavior and Its Underlying CNS Arousal Functions

This chapter addresses questions regarding lordosis behavior, the most extremely sexually differentiated behavior that has been analyzed for its neural and molecular mechanisms. Analysis of this behavior has proved for the first time that specific biochemical reactions in specific nerve cell groups in the brain determine a mammalian behavior. Lordosis is done by the female but not by the male. How did the process of sexual differentiation occur? A large literature implicates high levels of testosterone during a critical period during development as being responsible for the defeminization of the brain. A new idea, however, offers the possibility of direct genetic influences independent of testosterone levels themselves. We propose here that Mullerian Inhibiting Substance (MIS) and its receptors could constitute an example of a nonandrogenic genetic influence. Further, specific sexual behaviors depend on underlying arousal states in the central nervous system (CNS). We have proposed the concept of generalized CNS arousal and provide information as to how generalized arousal forces interact with specifically sexual influences, thus to facilitate sexually differentiated mating behaviors.

Expression ofSox9,Mis, andDmrt1 in the gonad of a species with temperature-dependent sex determination

Sex determination in vertebrates, the process of forming an ovary or testis from a bipotential gonad, can be initiated by genetic or environmental factors. Elements of the downstream molecular pathways underlying these different sex-determining mechanisms have been evolutionarily conserved. We find the first evidence that Sox9 expression is preferentially organized in the testis early in the temperature-sensitive period in a species with temperature-dependent sex determination (Trachemys scripta). This pattern occurs before sexually dimorphic Mis expression and in a temporal hierarchy that is similar to mammals. Furthermore, we extend previous findings that Dmrt1 expression at early stages of sex determination has a dimorphic pattern consistent with a possible upstream role in determining the fate of the bipotential gonad.

Association of anti-mullerian hormone levels with obesity in late reproductive-age women

OBJECTIVE

To describe anti-mullerian hormone (AMH) levels in healthy late reproductive age women and test the hypothesis that AMH levels are lower in obese compared to non-obese women.

DESIGN

Cross-sectional study of AMH levels. Longitudinal analysis of a subgroup with 10 AMH measures over 8 years to support the cross-sectional results.

SETTING

A population-based cohort of healthy late reproductive-age women.

PARTICIPANTS

Selected from the cohort to provide comparisons of body mass index (BMI), menopausal status, age and race (n = 122).

INTERVENTIONS

AMH levels were determined from blood samples collected in the parent study.

MAIN OUTCOME MEASURE

Serum levels of AMH.

RESULTS

AMH levels were 65% lower in obese women compared to non-obese women (0.016 ng/mL and 0.046 ng/mL, respectively). The geometric mean ratio was 0.35; 95% CI 0.13, 0.92, P=.034. AMH levels were significantly lower in the menopausal transition compared to premenopausal women and were significantly lower in all age groups > or =40 years compared to the 35-39 year-old women. BMI remained significantly associated with AMH levels in multivariable models that included adjustments for menopausal status, age, race and cycle day. In the longitudinal analysis of a subgroup, obese women had significantly lower mean AMH levels over the 8-year interval compared to the non-obese women (0.459 ng/mL; CI 0.28, 0.75 and 0.566 ng/mL; CI 0.34, 0.94, respectively; P=.016), corroborating the cross-sectional study results.

CONCLUSIONS

Obese women have lower AMH levels compared to non-obese women in the late reproductive years. The findings offer further evidence of the complex relationships between obesity and reproductive hormone levels in women.

Anti-Müllerian hormone measurement on any day of the menstrual cycle strongly predicts ovarian response in assisted reproductive technology

BACKGROUND

Recently, a new marker, the anti-Müllerian hormone (AMH), has been evaluated as a marker of ovarian response. Serum AMH levels have been measured at frequent time-points during the menstrual cycle, suggesting the complete absence of fluctuation. The aim of this study was to evaluate whether serum AMH measurement on any day of the menstrual cycle could predict ovarian response in women undergoing assisted reproductive technology (ART).

METHODS

This study included 48 women attending the IVF/ICSI programme. Blood withdrawal for AMH measurement was performed in all the patients independently of the day of the menstrual cycle.

RESULTS

Women in the lowest AMH quartile (<0.4 ng/ml) were older and required a higher dose of recombinant FSH than women in the highest quartile (>7 ng/ml). All the cancelled cycles due to absent response were in the group of the lowest AMH quartile, whereas the cancelled cycles due to risk of ovarian hyperstimulation syndrome (OHSS) were in the group of the highest AMH quartile. This study demonstrated a strong correlation between serum AMH levels and ovarian response to gonadotrophin stimulation.

CONCLUSION

For the first time, clinicians may have a reliable serum marker of ovarian response that can be measured independently of the day of the menstrual cycle.

Estradiol and regulation of anti-Müllerian hormone, inhibin-A, and inhibin-B secretion: analysis of small antral and preovulatory human follicles' fluid

CONTEXT

In ovaries surgically removed for fertility preservation, hormone concentrations in fluid from small antral follicles were determined. Levels were compared with those found in preovulatory follicular fluid.

OBJECTIVE

The objective of this study is to measure intrafollicular concentrations of anti-Müllerian hormone (AMH), inhibin-A, inhibin-B, estradiol, and progesterone.

SETTING

The study was set in a university hospital.

PATIENTS

Patients were 22 women suffering from a cancer disease and 16 women undergoing assisted reproduction.

INTERVENTIONS

Fluid from 35 follicles (diameter, 3-8 mm) was included and compared with that of 32 preovulatory follicles.

MAIN OUTCOME MEASURES

The main outcome measures were intrafollicular concentrations of the measured hormones and their possible correlation.

RESULTS

Concentrations of AMH in small antral follicles were almost three orders of magnitude higher than in follicle fluid of preovulatory follicles, 790 +/- 95 vs. 1.17 +/- 0.14 ng/ml (mean +/- sem), respectively. There was a significant negative correlation between estradiol and AMH in fluid from small antral follicles, whereas inhibin-A and inhibin-B were correlated positively with estradiol concentrations. Progesterone showed a similar correlation to levels of AMH but only in fluid of preovulatory follicles.

CONCLUSIONS

The high expression of AMH in granulosa cells of small antral follicles actually translates into very high follicle fluid AMH concentrations. This most likely explains the correlation between serum AMH levels and the number of small antral follicles as previously demonstrated. The negative correlation between estradiol and AMH suggests that FSH down-regulates AMH expression. Thus, the microenvironment of the follicle shows profound changes with developmental stage and highlights the importance of studies to understand the mechanisms that regulate follicular growth and development during antral stages of development.

Development of engineered antibodies specific for the Müllerian inhibiting substance type II receptor: a promising candidate for targeted therapy of ovarian cancer

The Müllerian inhibiting substance type II receptor (MISIIR) is involved in Müllerian duct regression as part of the development of the male reproductive system. In adult females, MISIIR is present on ovarian surface epithelium and is frequently expressed on human epithelial ovarian cancer cells. Müllerian inhibiting substance has been found to be capable of inhibiting the growth of primary human ovarian cancer cells derived from ascites and ovarian cancer cell lines. This suggested to us that MISIIR could be an attractive target for antibody-based tumor targeting and growth inhibition strategies. Here, we describe the production of recombinant human MISIIR extracellular domain-human immunoglobulin Fc domain fusion proteins and their use as targets for the selection of MISIIR-specific human single-chain variable fragments (scFv) molecules from a human nonimmune scFv phage display library. The binding kinetics of the resulting anti-MISIIR scFv clones were characterized and two were employed as the basis for the construction of bivalent scFv:Fc antibody-based molecules. Both bound specifically to human ovarian carcinoma cells in flow cytometry assays and cross-reacted with mouse MISIIR. These results indicate that antibody-based constructs may provide a highly specific means of targeting MISIIR on human ovarian carcinoma cells for the purpose of diagnosing and treating this disease.