Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Gonad development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed2005

[Aromatase inhibitor letrozole induces sex inversion in the protogynous red spotted grouper (Epinephelus akaara).].

The objective of this study was to investigate the effects of the aromatase inhibitor (AI) letrozole on gonadal development, serum steroids and aromatase activities in 2-year-old female red spotted grouper (Epinephelus akaara) during reproductive season. Groupers were divided into two groups, one implanted with aromatase inhibitor (AI, 5 mg/kg body weight) and the other elastomer without AI into peritoneal cavity once every four weeks for 8 weeks. Spermiation was checked through gentle abdominal pressure every 2 weeks. Blood samples were obtained from 6 fish of each group every 4 weeks for later analysis of sex steroids. After blood samples were collected, forebrain, midbrain, hindbrain, and gonads were collected and stored at -70 degrees C for later aromatase activity measurement and gonadal histological study. Significantly lower gondadosomatic index (GSI) was observed in AI-implanted group. Fish implanted with AI once showed complete degradation of oocytes and sex inversion with developing testicular tissues in the 4th week. AI induced females to develop into functional males with authentic males testes similar in structure to those in normal males. Spermiating rate of AI-treated males were 14.3%, 35.3%, and 48.4%in the 4th, 6th, and 8th week, respectively, while all fish in the control group were still female with developing ovaries. Aromatase activities in gonads decreased significantly after implantation with aromatase inhibitor, but showed no significant difference between control and AI-implanted group. No difference in serum testosterone (T) levels was observed in control and AI-treated group, while serum levels of 17beta-estradiol (E(2)) decreased but 11-ketotestosterone (11-KT) concentration increased significantly. The present results suggest that the decrease in serum 17beta-estradiol (E(2)) and increase in 11-KT levels may be important for sex inversion induced by aromatase inhibitor in red spotted grouper.

English Abstract↗
PubMed1995

Widespread expression of the testis-determining gene SRY in a marsupial.

There is compelling evidence from mutation analysis and transgenesis that the SRY gene isolated from human and mouse encodes the testis-determining factor on the mammalian Y chromosome. However, how SRY achieves this function is unclear. Although marsupials have been separated from eutherian mammals for approximately 100 million years, homologues of SRY have been localised to the Y chromosome of two unrelated marsupial species, the tammar wallaby and the Darling Downs dunnart. Gonadal development is fundamentally similar in eutherian and marsupial mammals, but the timing of morphological events is different. Fetal Sry transcripts are confined to somatic cells of the male mouse genital ridge between 10.5-12.5 days post coitum, corresponding with the onset of testis differentiation. Analysis of Sry gene expression in the genital ridge of normal and germ cell-deficient fetal mice has established that this gene acts in the somatic cell lineage, and is presumed to induce the formation of Sertoli cells. This assumption can be tested more critically in the tammar, where the equivalent stages of testis differentiation are observed over a 7-day period. We have examined the relationship of SRY expression to testis differentiation in the tammar wallaby. We show the marsupial SRY gene cannot be exclusively coupled to Sertoli cell differentiation, as this gene is expressed in the male fetus from several days before genital ridge formation until 40 days after birth. SRY transcripts are also present in a variety of extra-gonadal tissues in the developing young and adult male, a pattern of SRY expression similar to that observed in humans. These data indicate that, in addition to a role in testis determination, SRY may have other functions [corrected].

Animals↗
PubMed2005

DSH-2 regulates asymmetric cell division in the early C. elegans somatic gonad.

Like other organs, the C. elegans gonad develops from a simple primordium that must undergo axial patterning to generate correct adult morphology. Proximal/distal (PD) polarity in the C. elegans gonad is established early during gonadogenesis by the somatic gonad precursor cells, Z1 and Z4. Z1 and Z4 each divide asymmetrically to generate one daughter with a proximal fate and one with a distal fate. PD polarity of the Z1/Z4 lineages requires the activity of a Wnt pathway that activates the TCF/LEF homolog pop-1. How the gonadal pathway controlling pop-1 is regulated by upstream factors has been unclear, as neither Wnt nor Dishevelled (Dsh) proteins have been shown to be required. Here we show that the C. elegansdsh homolog dsh-2 controls gonadal polarity. As in pop-1 mutants, dsh-2 hermaphrodites have Z1 and Z4 lineage defects indicative of defective PD polarity and are missing gonadal arms. Males have an elongated but disorganized gonad, also with lineage defects. DSH-2 protein is expressed in the Z1/Z4 gonadal precursor cells. Asymmetric distribution of nuclear GFP::POP-1 in Z1 and Z4 daughter cells is reversed in dsh-2 mutants, with higher levels in distal than proximal daughters. dsh-2 and the frizzled receptor homolog lin-17 have a strong genetic interaction, suggesting that they act in a common pathway. We suggest that DSH-2 functions as an upstream regulator of POP-1 in the somatic gonad to control asymmetric cell division, thereby establishing proximal-distal polarity of the developing organ.

Alleles↗
PubMed1986

Gonadal failure following busulfan therapy in an adolescent girl.

A girl with Philadelphia chromosome-positive CML (Ph1-positive CML) was treated with busulfan from the age of 10 years 11 months to 16 years. Before treatment she had no evidence of pubertal development and no sexual development has occurred over the ensuing 5 years. Endocrine evaluation revealed that the child had ovarian failure. The pubescent female appears to be prone to develop gonadal failure with resultant lack of sexual development when treated with busulfan during this period in her life.

Adolescent↗
PubMed1996

Molecular analysis in true hermaphrodites with different karyotypes and similar phenotypes.

True hermaphroditism is characterized by the development of ovarian and testicular tissue in the same individual. Müllerian and Wolffian structures are usually present, and external genitalia are often ambiguous. The most frequent karyotype in these patients is 46,XX or various forms of mosaicism, whereas 46,XX is very rarely found. The phenotype in all these subjects is similar. We studied 10 true hermaphrodites. Six of them had a 46,XX chromosomal complement: 3 had been reared as males and 3 as females. The other 4 patients were mosaics: 3 were 46,XX/46,XY and one had a 46,XX/47,XXY karyotype. One of the 46,XX/46,XY mosaics was reared as a female, whereas the other 3 mosaics were reared as males. The sex of assignment in the 10 patients depended only on labio-scrotal differentiation. Molecular studies in 46,XX subjects documented the absence of Y centromeric sequences in all cases, arguing against hidden mosaicism. One patient presented Yp sequences (ZFY+, SRY+), which contrast with South African black 46,XX true hermaphrodites in whom no Y sequences were found. Molecular analysis in the subjects with mosaicism demonstrated the presence of Y centromeric and Yp sequences confirming the presence of a Y chromosome. Gonadal development, endocrine function, and phenotype in the 10 patients did not correlate with the presence of a Y chromosome or Y-derived sequences in the genome, confirming that true hermaphroditism is a heterogeneous condition.

Adolescent↗
PubMed1984

Effects of timed melatonin infusions on reproductive development in the Djungarian hamster (Phodopus sungorus).

In confirmation of earlier work, daily melatonin infusions of 9- or 12-h duration inhibited testicular development in pinealectomized juvenile Djungarian hamsters, while daily infusions of 6-h duration did not prevent gonadal growth. Two other methoxyindoles (5-methoxytryptophol and 5-methoxytryptamine) had less than 4% of the activity shown by melatonin. When pinealectomized hamsters received two short duration (i.e. 3, 5, or 6 h) melatonin infusions each day, gonadal development was not inhibited if the two daily infusions were separated by a period of 2 or 3 h without melatonin treatment. Thus, the effects of separate pulses of melatonin were not additive in this paradigm. When single, short duration daily infusions of melatonin (5-h) or isoproterenol (6-h) were administered to pineal-intact hamsters, gonadal inhibition occurred only when the infusions were given at times that would lead to an expected overlap with and extension of the endogenous nocturnal melatonin peak. Significant inhibition of testicular growth could be obtained with as few as 2-4 days of melatonin treatment. These observations further support the importance of melatonin peak duration and also indicate other interesting temporal aspects of melatonin action in the Djungarian hamster.

Aging↗
PubMed1995

Absence of mutations in the WT1 gene in patients with XY gonadal dysgenesis.

The WT1 gene is normally expressed during gonadal development and specific mutations in heterozygous form cause Drash syndrome, characterized by male pseudohermaphroditism and gonadal dysgenesis, renal failure and a predisposition for Wilms' tumour. These observations prompted us to test whether WT1 mutations are involved in isolated gonadal dysgenesis, being the most severe form of disturbance in gonadal differentiation. We studied 27 cases of 46,XY females with gonadal dysgenesis who had previously been screened for and found not to carry SRY gene mutations. We performed mutational screening of the WT1 gene with denaturing gradient gel electrophoresis. In one of these patients, a heterozygous point mutation in exon 8 was found. This mutation has previously been described in Drash syndrome and re-evaluation of the clinical data confirmed this diagnosis. Based on these results, we conclude that isolated gonadal dysgenesis is not caused by mutations in the WT1 gene.

DNA↗
PubMed1994

[Genes of the Y chromosome and Turner syndrome].

Turner syndrome is a complex human phenotype most commonly seen in association with a 45,X karyotype and it has been proposed that the phenotype is the result of monosomy for genes common to the X and Y chromosomes. Detection of unrecognized Y derived material is now possible by PCR of the SRY gene. Its presence is correlated with the presence of testicular tissue, known to increase the risk of developing gonadal neoplasia. Study of Y chromosome allowed the localisation of a candidate gene for the development of gonadoblastoma, GBY. Moreover, some groups described genes on the Y chromosome whose defects seem to be involved in the development of Turner stigmata: ZFY and RPS4Y. In conclusion; molecular genetics of the Y chromosome develops new pathophysiological and fundamental perspectives of the molecular genetics of the Turner syndrome.

Chromosome Mapping↗
PubMed2000

The C. elegans gene lin-9,which acts in an Rb-related pathway, is required for gonadal sheath cell development and encodes a novel protein.

The Caenorhabditis elegans gene lin-9 functions in an Rb-related pathway that acts antagonistically to a receptor tyrosine kinase/Ras signal transduction pathway controlling vulval induction. We show that lin-9 is also required for the development of the sheath cells in the hermaphrodite gonad and for the development of the male spicule, rays and gonad. lin-9 is transcribed as two alternatively spliced 2.4kb messages, which use two distinct polyadenylation sites and are SL1 trans-spliced. The conceptual translation of lin-9 cDNA sequences predicts proteins of 642 and 644 amino acids with a significant similarity to predicted Drosophila and vertebrate proteins. We suggest that lin-9 is the founding member of a new protein family that functions in Rb-related pathways in many species.

Alternative Splicing↗
PubMed2002

Divergent vascular mechanisms downstream of Sry establish the arterial system in the XY gonad.

Although the primitive vasculature is identical in XX and XY genital ridges until 11.5 days postcoitum (dpc), by 12.5 dpc the XY gonad develops a distinct vasculature. This male-specific vasculature, which includes the development of a large coelomic vessel, develops coincident with expression of Sry and formation of testis cords. We show that similar levels of proliferation and vasculogenesis expand the primary vasculature in XX and XY gonads. However, soon after Sry expression begins, the XY gonad recruits a large number of endothelial cells from the adjacent mesonephros, a mechanism totally absent in XX gonads. These migrating cells do not contribute to venous or lymphatic development. Instead, these cells contribute to the arterial system, as indicated by expression of ephrinB2 and by elements of the Notch signaling pathway. This newly formed arterial system establishes a new pattern of blood flow in the XY gonad, which we speculate may have an important role in export of testosterone to masculinize the XY embryo.

Animals↗
PubMed2004

Alternative morphs and plasticity of vulval development in a rhabditid nematode species.

The nematode species Rhabditis sp. SB347 (Family Rhabditidae) in standard culture conditions displays two developmental morphs with distinct modes of sexual reproduction: (1). females and males that develop through four feeding juvenile ("larval") stages; (2). self-fertile protandric hermaphrodites that develop through an obligatory non-feeding third juvenile stage, the "dauer" larva. In females and males, somatic gonad development begins in the first larval stage, whereas in hermaphrodites it is delayed to the second larval stage. Vulval development also differs between females and hermaphrodites: (1). the P8.p cell divides in females but stays undivided in hermaphrodites; (2). the number, timing, and source of inductive signals from the gonad to the vulval precursor cells differ between the two morphs. These results show that discrete vulva developmental routes can be adopted by animals of the same genotype.

Animals↗
PubMed2006

Presence of ectopic adrenocortical tissues in inguinoscrotal region suggests an association with undescended testis.

Ectopic adrenocortical tissues (EAT) are rare pathologies in children. They are frequently encountered in the inguinal region incidentally during surgical procedures but they are also classically known to be located from diaphragm to pelvis. EAT were investigated during inguinal procedures including inguinal hernia, hydrocele, hydrocele of cord and undescended testis (UDT) in 1,069 patients, 159 girls, 910 boys, from April 1997 until April 2006. All these nodules were confirmed to be adrenocortical tissues after histopathological examinations. Statistical analysis was done with Fisher's exact test. EAT were noted on the plexus pampiniformis external to processus vaginalis of 22 male patients (1.73%) during inguinal explorations. This figure was 1.63% for inguinal explorations of inguinal hernia, hydrocele and hydrocele of cord and 5.1% for UDT. This difference was statistically significant (P<0.0001). There were no EAT detected during inguinal exploration of female patients. EAT are uncommon pathologies seen during inguinoscrotal explorations. Incidence of EAT is significantly increased with UDT. This increase may be explained with the embryological events that take place during adrenal and gonadal development. The relatively low observation of EAT in girls may be due to the localization of gonads and association of EAT with gonadal position. Adrenal rests in inguinal region may suggest an association with descent of gonads.

Adrenal Cortex↗
PubMed2004

Spatio-temporal expression of a DAZ-like gene in the Japanese newt Cynops pyrrhogaster that has no germ plasm.

To investigate the germ cell specification in urodeles, we cloned a DAZ-like sequence from the Japanese newt Cynops pyrrhogaster, Cydazl, and raised antibodies specific to Cydazl. Cydazl is a homologue of the human DAZ (deleted in azoospermia), DAZL, and Xenopus dazl genes, which are involved in gametogenesis or germ cell specification. During gametogenesis, expression of Cydazl mRNA and Cydazl protein was detected at first in the small previtellogenic oocytes in females but was not localized as seen in Xenopus and was restricted to secondary spermatogonia prior to meiosis in males. During early embryogenesis, maternal stores of the Cydazl transcript and protein were present in the entire embryos, not localized in any specific region. The zygotic expression was detected in hatching larvae (stage 50) by RT-PCR analysis whereas specific cells expressing Cydazl could not be determined by in situ hybridization at this stage. Strong expression of Cydazl and Cydazl were detected in primordial germ cells (PGCs) that had entered the gonadal rudiment at late stage 59. These results suggest that Cydazl does not function early in development, for the specification of germ cells, but functions later for differentiation of germ cells in the developing gonads during embryogenesis and for meiotic regulation, supporting the previous idea of an intermediate germ cell formation mode in urodeles.

Amino Acid Sequence↗
PubMedDate not supplied

Inheritance of T-associated sex reversal in mice.

We previously identified a primary sex-determining locus, Tas, on mouse Chr 17 that causes ovarian tissue development in C57BL/6J Thp/+ and TOrl/+ individuals if the AKR/JY chromosome is present. We hypothesized that Tas is located within the region of Chr 17 deleted by Thp and TOrl and that C57BL/6J carries a diagnostic Tas allele, based on the observation that ovarian tissue develops in XY mice when Thp is on a C57BL/6J inbred strain background, whereas normal testicular development occurs when Thp is on a C3H/HeSnJ inbred strain background. To test this hypothesis, we mated (C57BL/6J x C3H/HeSnJ)F1 females to C57BL/6J Thp/+ hermaphrodites. As expected, half of the XY Thp/+ offspring developed ovarian and testicular tissue while half developed exclusively testicular tissue. Unexpectedly, the inheritance of selected Chr 17 molecular loci was independent of gonadal development, as half of the male and hermaphroditic offspring inherited C3H/HeSnJ-derived Chr 17 loci and half inherited C57BL/6J-derived Chr 17 loci. We conclude that for ovarian tissue to develop in an XY Thp/+ or XY TOrl/+ individual (1) Tas must be present in a hemizygous state, which is accomplished by heterozygosity for the Thp or TOrl deletions; (2) the AKR/J-derived Y chromosome must be present; and (3) an additional locus involved in primary sex determination must be present in a homozygous C57BL/6J state. This newly identified gene may be one of the previously defined loci, tda-1 or tda-2.

Animals↗
PubMed2006

Exposure, postexposure, and density-mediated effects of atrazine on amphibians: breaking down net effects into their parts.

Most toxicology studies focus on effects of contaminants during exposure. This is disconcerting because subsequent survival may be affected. For instance, contaminant-induced mortality can be later ameliorated by reduced competition among the survivors, a concept we refer to as "density-mediated compensation." Alternatively, it can be exacerbated by toxicant effects that persist or appear after exposure, a phenomenon we term "carryover effects." We developed a laboratory framework for testing the contribution of exposure, density-mediated, and carryover effects to net survival, by exposing embryos and larvae of the streamside salamander (Ambystoma barbouri) to atrazine (0, 4, 40, 400 ppb; 3 ppb is the U.S. drinking water maximum) and quantifying survival during and 14 months after exposure. Atrazine is the most commonly used herbicide in the United States and a documented endocrine disruptor. We show that atrazine-induced mortality during exposure was ameliorated by density-dependent survival after exposure, but complete density-mediated compensation was precluded by significant carryover effects of atrazine. Consequently, salamanders exposed to >or=4 ppb of atrazine had significantly lower survival than did control animals 14 months postexposure. The greatest change in survival occurred at low exposure concentrations. These nonlinear, long-term, postexposure effects of atrazine have similarities to effects of early development exposure to other endocrine disruptors. Together with evidence of low levels of atrazine impairing amphibian gonadal development, the results here raise concerns about the role of atrazine in amphibian declines and highlight the importance of considering persistent, postexposure effects when evaluating the impact of xenobiotics on environmental health.

Animals↗
PubMed2005

Somatic control of germline sexual development is mediated by the JAK/STAT pathway.

Germ cells must develop along distinct male or female paths to produce the sperm or eggs required for sexual reproduction. In both mouse and Drosophila, the sexual identity of germ cells is influenced by the sex of the surrounding somatic tissue (for example, refs 1, 2, reviewed in refs 3, 4); however, little is known about how the soma controls germline sex determination. Here we show that the janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway provides a sex-specific signal from the soma to the germ line in Drosophila embryonic gonads. The somatic gonad expresses a JAK/STAT ligand, unpaired (upd), in a male-specific manner, and activates the JAK/STAT pathway in male germ cells at the time of gonad formation. Furthermore, the JAK/STAT pathway is necessary for male-specific germ cell behaviour during early gonad development, and is sufficient to activate aspects of male germ cell behaviour in female germ cells. Our findings provide direct evidence that the JAK/STAT pathway mediates a key signal from the somatic gonad that regulates male germline sexual development.

Animals↗
PubMed1988

Sensitive periods during embryogeny for hormonally induced sex determination in turtles.

Administration of exogenous estradiol between embryonic stages 10 and 19 inclusive caused embryos of snapping turtles (a species which exhibits temperature-dependent sex determination) to develop ovaries rather than testes, while administration of hormone either prior to stage 10 or after stage 22 did not affect the predicted sex ratio of offspring. Thus the sensitive period for hormonal effects on gonadal development apparently coincides with the period of normal gonadal differentiation. In light of these and prior results use of the term "sex reversal" when discussing the effects of hormones on gonadal differentiation may be a misnomer. We suggest the alternative phrase "hormonally induced gonadal differentiation" (HGD) as a substitute. Results also indicate that variations in the timing of injections among studies may account for at least some of the interspecific differences previously reported for effects of exogenous hormones on gonad differentiation.

Animals↗
PubMed1998

Discordant phenotypes and 45,X/46,X,idic(Y).

Mosaicism introduces wide variability into the clinical expression of numerical and unbalanced structural chromosomal abnormalities. The phenotypic range of variability of 45,X/46,XY mosaicism extends from Turner syndrome to mixed gonadal dysgenesis to normal males. The specific phenotype is primarily dependent on the chromosomal constitution of the developing gonad. Similar phenotypic variability is observed with mosaicism for 45,X and a second cell line with an abnormal sex chromosome. This report describes a patient with Turner syndrome and a patient with mixed gonadal dysgenesis who have identical karyotypes, namely 45,X/46,X,idic(Y)(p11.2). While mosaicism alone might have accounted for the phenotypic differences, by PCR analysis the Turner syndrome patient was SRY and ZFY negative and the mixed gonadal dysgenesis patient was SRY and ZFY positive.

Adolescent↗