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PubMed2026

Genome-wide identification and expression profiling of HSD3B and SDR42E1 genes in the Pacific oyster (Crassostrea gigas): potential associations with gonadal development.

Sex steroids are lipid-soluble signaling molecules that regulate sex differentiation, reproductive development and physiological homeostasis in animals. 3β-Hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase (3β-HSD) is a key steroidogenic enzyme, whereas SDR42E1, an extended short-chain dehydrogenase/reductase, has been implicated in sterol- and steroid-related metabolism. However, the composition, evolutionary relationships and expression patterns of the HSD3B- and SDR42E1-related genes in bivalve gonadal development remain poorly characterized. In this study, five PF01073-containing genes, comprising three CgHsd3b and two CgSdr42e1 genes, were identified in the Pacific oyster Crassostrea gigas. Phylogenetic analysis separated the proteins into HSD3B-related and SDR42E1-related groups, and gene-structure and motif analyses indicated subfamily-level divergence. All five proteins retained the SDR domain but differed in exon-intron structure and motif composition. Each contained the extended-SDR TGxxGxxG motif, whereas exact classical [ST]GxxxGxG and NNAG motifs were absent. Tyr- and Lys-equivalent residues were conserved, while the HSD3B1 Ser-equivalent position contained Thr in two C. gigas proteins and Ser in one. These features support their classification as extended-SDR proteins but do not establish enzymatic activity or substrate specificity. The three CgHsd3b genes were dispersed on one chromosome, whereas CgSdr42e1-1 and CgSdr42e1-2 were adjacent on another chromosome, suggesting a possible local duplication event for the CgSdr42e1 pair. Public RNA-seq data showed distinct tissue- and gonadal-stage expression patterns, with several genes displaying gonad-biased or female-stage-associated expression. Independent RT-qPCR profiling of the representative genes CgHsd3b-3 and CgSdr42e1-1 detected stage-dependent expression, although tissue rankings differed from those in the public RNA-seq datasets. These differences may reflect the use of independent biological samples, tissue composition, normalization procedures, and platform-specific measurements. Because enzymatic assays, metabolite measurements, cellular localization, and functional perturbation were not performed, the results identify candidate genes whose expression is associated with gonadal development rather than demonstrating regulatory roles. This study provides a comparative framework for future functional investigation of sterol- and steroid-related metabolism in bivalves.

Animals↗
PubMed2002

Genes essential for early events in gonadal development.

The acquisition of a sexually dimorphic phenotype is a key event in mammalian development. The underlying principle of this essential process is that genetic sex, determined by the presence or absence of a Y chromosome at fertilization, directs the embryonic gonads to differentiate into either testes or ovaries. Hormones produced by the testes then trigger the developmental program that leads to male phenotypic sexual differentiation. Without testes and their biochemical products, differentiation proceeds along the female pathway. Recent studies have identified several transcription factors that are required for gonadal development and sexual differentiation, i.e. Wilms' tumor related 1 (WT1), steroidogenic factor 1 (SF-1), SOX9, and GATA4, presumably because they activate the expression of essential target genes. Studies also have identified another transcriptional regulator, designated DAX-1, that inhibits target gene induction by all of these transcriptional activators. This chapter provides an overview of gonadal development and sexual differentiation, reviews the studies that have led to the isolation and characterization of these genes in the gonads, and then discusses how they interact to regulate critical events in sexual differentiation.

DAX-1 Orphan Nuclear Receptor↗
PubMed2002

Stage- and sex-dependent expressions of Usp9x, an X-linked mouse ortholog of Drosophila Fat facets, during gonadal development and oogenesis in mice.

During the Drosophila oogenic processes, Fat facets (Faf), an ubiquitin-specific protease essential for normal development of oocyte and eye, becomes localized at the posterior pole and is incorporated into the pole cells. This is dependent on Oskar, a key factor for pole cell determination, and suggests a role for Faf in germ cell differentiation and development. Here we show that Usp9x, an X-linked ortholog of Faf, is predominantly expressed in both germ cell and supporting cell lineages during mouse gonadal development in stage- and sex-dependent manners. Usp9x was first detected in PGCs at 10.5 days post coitum (dpc), and thereafter its expression both at mRNA and protein levels was enhanced in PGCs of both sexes at 11.5-13.5 dpc. In testis, Usp9x expression rapidly decreased to an undetectable level by 15.5 dpc and after birth to adult, no expression was found in any spermatogenic cells, except for weak expression in Sertoli cells. In the ovary, Usp9x expression in embryonic oocytes was also reduced at the newborn stage, its expression reappeared in oocytes at secondary follicle stage, and its products were highly accumulated in the cytoplasm of Graaffian follicles in adults. Although follicular epithelial cells also expressed Usp9x at a moderate level during postnatal development, its expression was downregulated from early secondary follicle stage. Thus, the present study is not only the first to demonstrate a conserved expression of fat facets in PGCs between mouse and fly, but also sex- and stage-dependent changes of a specific component of the deubiquitylation system during mammalian gonadal development.

Animals↗
PubMed1984

Thyroid and annual gonad development, body weight, plumage pigmentation, and bill color cycles of lal munia, Estrilda amandava.

Long-term administration of L-thyroxine (T4) in the wax bill (lal munia) inhibited the current gonad development cycle, and the increase in gonadal volume in the second cycle was suppressed only by higher concentrations. Gonadal inhibition by high but not by low doses of L-T4 was associated with a failure in the development of LH-dependent pigmented nuptial plumage. This suggests that L-T4 depresses FSH secretion more readily than LH secretion. The results indicate that the effects of L-T4 administration on the body weight cycle depends upon the physiological and/or gonadal status of the bird at the start of the experiment and that the juvenile hypothalamo-hypophysial-gonadal axis is more sensitive to L-T4 than that of the adult birds. The bill color, like plumage pigmentation, appears to be LH controlled. It is suggested that while thyroid hormone, acting by way of the hypothalamo-hypophysial complex and/or by direct action on the feather papillae, modulates the annual cycles of plumage pigmentation, bill color, gonad development, and body weight of lal munia, the finch has an endogenous mechanism which enables it to adapt to chronic hyperthyroidism in such a way that breeding occurs at the normal time of the year.

Animals↗
PubMed1999

Steroid levels and steroid metabolism in relation to early gonadal development in the tilapia Oreochromis niloticus (Teleostei: cyprinoidei).

Sex steroid levels and steroid metabolism were investigated in relation to early gonadal development in a mixed sex population of the tilapia Oreochromis niloticus. Androstenedione (AD), testosterone (T), 11-ketotestosterone (KT), and estradiol (E2) were quantified by radioimmunoassay (RIA) of whole body extracts. Androstenedione metabolism was assessed by incubations in vitro with 3H-AD and metabolites were identified by thin-layer chromatography coupled with radioisotope image analysis. Histology revealed the presence of gonadal structures at 15 days postfertilization (dpf) and ovaries at 36 dpf, with other individuals exhibiting undifferentiated gonads containing germinal cells, presumably eventual testes. Androgen levels were initially high in eggs then decreased severalfold prior to the emergence of gonads. A transient increase in the levels of T and KT occurred at 22 dpf. Levels of E2 were either low or undetectable except for a transient increase (43 dpf) after ovaries were present. Levels of T approached bimodality from 57 to 64 dpf. Steroid metabolism generally increased throughout development. Metabolites were generally similar, consisting of T predominantly as well as 5beta-reduced androgen derivatives and 11-oyxgenated derivatives. Estriol was tentatively identified. Conjugated steroids were not formed. Two types of steroid metabolic profiles occurred at 50 dpf. These results demonstrate that changes in the steroidogenic profile occur during early transitions of gonadal development. Notably, (1) steroid biosynthetic capacity preceeds gonadal differentiation, (2) evidence for estrogens occurs after ovarian development has begun, and (3) bimodality of levels of T and differential steroid metabolism later in development may reflect the onset of sexual divergence.

Androstenedione↗
PubMed2002

Stage- and sex-dependent expressions of Usp9x, an X-linked mouse ortholog of Drosophila Fat facets, during gonadal development and oogenesis in mice.

During the Drosophila oogenic processes, Fat facets (Faf), an ubiquitin-specific protease essential for normal development of oocyte and eye, becomes localized at the posterior pole and is incorporated into the pole cells. This is dependent on Oskar, a key factor for pole cell determination, and suggests a role for Faf in germ cell differentiation and development. Here we show that Usp9x, an X-linked ortholog of Faf, is predominantly expressed in both germ cell and supporting cell lineages during mouse gonadal development in stage- and sex-dependent manners. Usp9x was first detected in PGCs at 10.5 days post coitum (dpc), and thereafter its expression both at mRNA and protein levels was enhanced in PGCs of both sexes at 11.5-13.5 dpc. In testis, Usp9x expression rapidly decreased to an undetectable level by 15.5 dpc and after birth to adult, no expression was found in any spermatogenic cells, except for weak expression in Sertoli cells. In the ovary, Usp9x expression in embryonic oocytes was also reduced at the newborn stage, its expression reappeared in oocytes at secondary follicle stage, and its products were highly accumulated in the cytoplasm of Graaffian follicles in adults. Although follicular epithelial cells also expressed Usp9x at a moderate level during postnatal development, its expression was downregulated from early secondary follicle stage. Thus, the present study is not only the first to demonstrate a conserved expression of fat facets in PGCs between mouse and fly, but also sex- and stage-dependent changes of a specific component of the deubiquitylation system during mammalian gonadal development.

Animals↗
PubMed2006

The effects of calcium, phosphorus, magnesium, sodium, and zinc in improving the depression of gonadal development in growing male rats kept under a disturbed daily rhythm-investigations based on the L(16)(2(15))-type orthogonal array.

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. This experimental protocol was designed based on the L16(2(15))-type orthogonal array, which can examine six factors. Five minerals (calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), and zinc (Zn)) were selected as experimental factors, and the dietary content of these minerals was normal (AIN-76 diet) or 1/3.5 of the normal content. Lighting conditions (constant darkness or normal lighting) were also added as a factor. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. After 4 wk, the gonadal weights and serum testosterone content were evaluated. The lighting condition, Ca, Mg, and Na, and the interactions between the lighting condition and Ca, and Mg and Na were observed to affect the testes weight. Among the constant darkness groups (D-groups), the highest value for testes weight was observed under the normal-Ca, normal-Mg, and normal-Na diet, and the lowest value was observed under the low-Ca, normal-Mg, and low-Na diet. Among the normal lighting groups (N-groups), the highest value for testes weight was observed under the low-Ca, normal-Mg, and normal-Na diet, and the lowest value was observed under the normal-Ca, normal-Mg, and low-Na diet. Among the D-groups, the highest value for serum testosterone was observed under the normal-Ca, normal-Mg, and low-Na diet. Among the N-groups, the highest value was observed under the low-Ca, normal-Mg, and low-Na diet. It became clear that the amount of dietary Ca necessary for the gonadal development of rats increases when rats are kept under constant darkness as a model of disturbed daily rhythm compared with the normal lighting condition.

Analysis of Variance↗
PubMed2005

Characterization and expression pattern of zebrafish Anti-Müllerian hormone (Amh) relative to sox9a, sox9b, and cyp19a1a, during gonad development.

The role of Anti-Müllerian hormone (Amh) during gonad development has been studied extensively in mammals, but is less well understood in other vertebrates. In male mammalian embryos, Sox9 activates expression of Amh, which initiates the regression of the Mullerian ducts and inhibits the expression of aromatase (Cyp19a1), the enzyme that converts androgens to estrogens. To better understand shared features of vertebrate gonadogenesis, we cloned amh cDNA from zebrafish, characterized its genomic structure, mapped it, analyzed conserved syntenies, studied its expression pattern in embryos, larvae, juveniles, and adults, and compared it to the expression patterns of sox9a, sox9b and cyp19a1a. We found that the onset of amh expression occurred while gonads were still undifferentiated and sox9a and cyp19a1a were already expressed. In differentiated gonads of juveniles, amh showed a sexually dimorphic expression pattern. In 31 days post-fertilization juveniles, testes expressed amh and sox9a, but not cyp19a1a, while ovaries expressed cyp19a1a and sox9b, but not amh. In adult testes, amh and sox9a were expressed in presumptive Sertoli cells. In adult ovaries, amh and cyp19a1a were expressed in granulosa cells surrounding the oocytes, and sox9b was expressed in a complementary fashion in the ooplasm of oocytes. The observed expression patterns of amh, sox9a, sox9b, and cyp19a1a in zebrafish correspond to the patterns expected if their regulatory interactions have been conserved with mammals. The finding that zebrafish sox9b and sox8 were not co-expressed with amh in oocytes excludes the possibility that amh expression in zebrafish granulosa cells is directly regulated by either of these two genes.

Amino Acid Sequence↗
PubMed2000

Germ and somatic cell lineages in the developing gonad.

The germ cell lineage in the mouse becomes lineage-restricted about 7.2 days post coitum. Its progenitors have migrated from the proximal region of the epiblast, where they were subject to a predisposing signal from the adjacent extra-embryonic ectoderm. It appears that this and other signals determine the emergence of germ cells: unlike in some other organisms, this event is not pre-determined. After about 24 h in their initial extraembryonic location, the primordial germ cells migrate back into the embryo and make their way into the region of the developing gonad. Less is known about the origin of the various somatic cell lineages in the gonad, but some are known to derive from cells that migrate in from the mesonephros and others from the coelomic epithelium. Within the developing gonad, numerous interactions occur between the germ and somatic cell lineages. These are particularly important for the establishment of the spermatogenic lineage in the testis and for the differentiation of somatic tissue in the ovary. This paper will describe first the development of the germ cell lineage, up until about the time of birth, then the various somatic components of the gonad and finally the interactions that are known to occur between lineages. Unless otherwise stated, all the information refers to the mouse.

Animals↗
PubMed1999

Growth Performance and Gonadal Development of Growth Enhanced Transgenic Tilapia Oreochromis niloticus (L.) Following Heat-Shock-Induced Triploidy.

Triploid induction offers a way of considerably reducing fertility in fish, and could therefore be employed to help ensure that any adverse environmental impact of transgenic fish was markedly less. In order to produce sterile growth-enhanced transgenic fish, we have induced triploidy in two lines of transgenic tilapia. Growth performance and gonadal development were analyzed following triploidization by heat shock. Ploidy status was confirmed by nuclear size measurement of erythrocytes. Erythrocytes of triploids were found to be 1.5 times larger than diploids. Observations of growth enhancement and gonadal development were made on diploids and triploids from both transgenic and nontransgenic full sibling batches. In both lines, transgenic diploids were superior in growth performance, followed by transgenic triploids, nontransgenic diploids, and nontransgenic triploids. Although the testes of transgenic triploids were significantly smaller than those of nontransgenic triploids and nontransgenic diploids, histologically they did not show signs of gross deformation. There were also some spermatozoa present in the testes of some triploids, which could be indicative of reproductive functionality. However, the ovaries were devoid of oocytes, underdeveloped, and deformed in all triploids and were completely nonfunctional. Although the best growth performance was shown by the fertile diploid transgenics, the triploid transgenic females could offer a good option for aquaculture purposes because they showed superior growth performance over the normal wild-type tilapias with the advantage of sterility to ensure nonhybridization and noncontamination with the local gene pool. However, careful monitoring of potential gene flow would be required prior to commercial use.

Journal Article↗
PubMed2004

[Morphological studies on embryonic gonad development in Kunming mice].

OBJECTIVE: To observe the morphological changes of embryonic gonad in Kunming mice in different developmental stages. METHODS: HE stained paraffin sections of the embryonic mouse gonads in different developmental stages were prepared for evaluation of the morphological changes. RESULTS: The genital ridge was identified on the 11th day after the mating and undifferentiated gonad detected on the 12th day, while 1 d later, sexual identification was possible by examining the sections. The male gonad developed into testis by forming seminiferous tubules and Sertoli cells on the 14th day. On the 16th day, the female gonad evolved into the ovary with obvious differentiation of the cortex and medulla and till the 20th day, more seminiferous tubules occurred in the testis with cavities containing numerous spermatogenic cells at different developing phases; also observed was a mass of rough sex cords that produced ovarian follicles surrounding the ovary and contained large quantity of primitive oogonia. CONCLUSIONS: Days 11-12 after mating might be the best time for separating primordial germ cells from undifferentiated mouse gonad.

Animals↗
PubMed2005

Gonadotropin-inhibitory hormone inhibits gonadal development and maintenance by decreasing gonadotropin synthesis and release in male quail.

Until recently, any neuropeptide that directly inhibits gonadotropin secretion had not been identified. We recently identified a novel hypothalamic dodecapeptide that directly inhibits gonadotropin release in quail and termed it gonadotropin-inhibitory hormone (GnIH). The action of GnIH on the inhibition of gonadotropin release is mediated by a novel G protein-coupled receptor in the quail pituitary. This new gonadotropin inhibitory system is considered to be a widespread property of birds and provides us with an unprecedented opportunity to study the regulation of avian reproduction from an entirely novel standpoint. To understand the physiological role(s) of GnIH in avian reproduction, we investigated GnIH actions on gonadal development and maintenance in male quail. Continuous administration of GnIH to mature birds via osmotic pumps for 2 wk decreased the expressions of gonadotropin common alpha and LHbeta subunit mRNAs in a dose-dependent manner. Plasma LH and testosterone concentrations were also decreased dose dependently. Furthermore, administration of GnIH to mature birds induced testicular apoptosis and decreased spermatogenic activity in the testis. In immature birds, daily administration of GnIH for 2 wk suppressed normal testicular growth and rise in plasma testosterone concentrations. An inhibition of juvenile molt also occurred after GnIH administration. These results indicate that GnIH inhibits gonadal development and maintenance through the decrease in gonadotropin synthesis and release. GnIH may explain the phenomenon of photoperiod-induced gonadal regression before an observable decline in hypothalamic GnRH in quail. To our knowledge, GnIH is the first identified hypothalamic neuropeptide inhibiting reproductive function in any vertebrate class.

Animals↗
PubMedDate not supplied

Diagnosis of abnormalities in gonadal development.

The role of the clinical laboratory in the diagnosis of abnormalities in gonadal development is reviewed, beginning with a description of the normal differentiation of the ovary and testis and the major types of disorders encountered. The conditions are classified as resulting from abnormal gonadal differentiation, defective endocrine function or excessive endocrine activity. Germ cell neoplasms are also reviewed. Laboratory procedures utilized in evaluation of gonadal abnormalities include cytogenetic, hormonal, and histopathologic studies. Standard procedures are described as well as newer method which have undergone increasing use in recent years and other specialized procedures which are under investigation for possible clinical application.

Androgen-Insensitivity Syndrome↗
PubMed2004

Mutations affecting gonadal development in Medaka, Oryzias latipes.

A gonad is formed from germ cells and somatic mesodermal cells through their interactions. Its development is coupled with the determination and differentiation of the sex and sex-associated traits. We carried out a large-scale screening of Medaka mutants in which gonadal development is affected. Screening was performed on larvae at 8 days posthatching for abnormal abundance and/or distribution of germ cells detected by the in situ hybridization for olvas (Medaka vasa). We describe here 16 mutants of 13 genes, which are classified into four groups. Group 1, consisting of four mutants of three genes kon, tot) characterised by an increase in germ cell number. An adult tot homozygote fish has the characteristic feature of possessing hypertrophic gonads filled with immature oocytes. Group 2, represented by a single gene (zen) mutant characterized by a gradual loss of germ cells. Group 3, consisting of four mutants of distinct genes (eko, eki, sht, ano) showing irregular clustering of germ cells. Group 4, consisting of seven mutants of five genes (arr, hyo, mzr, hdr, fbk) showing fragmented clusters of germ cells. In some mutants belonging to Groups 1, 3 and 4, the expression level of ftz-f1 (sf-1/Ad4BP) in gonadal somatic cells significantly decreased, suggesting that interaction between somatic and germ cells is affected.

Animals↗
PubMed2002

Isolation of the human testatin gene and analysis in patients with abnormal gonadal development.

We have previously isolated the testatin gene using a modified mRNA differential display method on RNA from developing male and female mouse gonads. This gene is specifically expressed during early testis development, immediately after the onset of the testis-determining gene SRY: The protein encoded by testatin has features that are characteristic for type 2 cystatins, a family of small inhibitors of cystein proteases such as the cathepsins. We have now isolated the human orthologue of this gene. We describe here the sequence, genomic structure, chromosomal location, and expression pattern of the human testatin gene. Like mouse testatin, human testatin is specifically expressed in the testis, suggesting that it has a function in reproduction. We have therefore also investigated whether the human testatin gene plays a role in disorders of gonadal development, by sequencing the gene in patients with gonadal dysgenesis, with true hermaphroditism, and in children with less well-defined intersex conditions. We found no sequence aberrations in these patients apart from an H109P polymorphism which was also found in fertile controls. This is the first genetic analysis of testatin in humans.

Amino Acid Sequence↗
PubMed1999

Gonadal development and growth of chickens and turkeys hatched from eggs injected with an aromatase inhibitor.

It was the purpose of these experiments to describe gonadal development and posthatching growth of genetic female chickens and turkeys following in ovo injection of the aromatase inhibitor Fadrazole (CGS 16949A) prior to incubation. In ovo injection of Fadrazole (CGS 16949A) resulted in the development of testes-like gonads in the majority of day-old genetic female chickens and turkey poults. Ninety-eight to 99% of these birds have masculine-type male genitalia at 1 d of age. Microscopic examination of the gonads of day-old genetic female chicks hatched from Fadrazole-treated eggs showed the presence of atypical seminiferous tubules in 3 of 18 individuals and the presence of ovarian follicles in 3 of 18 individuals. No germinal elements were seen in 12 individuals. The gonads in the majority (8/11) of day-old female poults from treated eggs showed the presence of atypical seminiferous tubules. Three of 11 individuals had structures characterized as disorganized or degenerate follicles. Between the day of hatch and 6 wk, gonads in an increasing proportion of female chickens from Fadrazole-treated eggs had normal appearing ovarian follicles. A similar trend was seen in the female turkeys between hatch and 12 wk of age. There were no differences in BW of female chickens hatched from Fadrazole-treated eggs and those from control eggs between the day of hatch and 6 wk of age. The pectoral muscle mass and fat pad weights of these birds did not differ. In one experiment, the BW of female turkeys hatched from Fadrazole-treated eggs was significantly greater than that of controls and equal to that of males at 3 and 6 wk of age. Thereafter, both types of females were of equal weight and significantly lighter than males. Fadrazole treatment did not affect pectoral muscle mass of either sex of turkeys.

Adipose Tissue↗
PubMed1999

TGF-beta Family Members and Gonadal Development.

Several members of the transforming growth factor beta (TGF-beta) family are involved in gonadal development; namely, TGF-beta itself, inhibins, activins, anti-Müllerian hormone (AMH) and GDF-9. These proteins do not affect initial gonadal organogenesis but play either a stimulatory or inhibitory role in the division and differentiation of gonadal cells and in meiotic maturation in the female. Furthermore, as shown by transgenic mouse technology, both AMH and inhibin act as tumor suppressors.

Journal Article↗
PubMed2005

Cloning of FSHbeta, LHbeta, and glycoprotein alpha subunits from the Russian sturgeon (Acipenser gueldenstaedtii), beta-subunit mRNA expression, gonad development, and steroid levels in immature fish.

The Russian sturgeon, Acipenser gueldenstaedtii, is a late-maturing Acipenseriformes. To elucidate the role of FSH and LH in its reproduction, we cloned its glycoprotein alpha-subunit (GPalpha) and gonadotropin beta-subunits (FSHbeta and LHbeta) using 5' and 3' RACE-PCR. The nucleotide sequences of the Russian sturgeon (st) GPalpha, FSHbeta, and LHbeta are 345, 384, and 411 bp long, encoding peptides of 91, 115, and 114 amino acids, respectively. The deduced amino acid sequence of each mature subunit showed high similarity with those of other teleosts. Sequence analysis showed that stFSHbeta is more similar to higher vertebrate FSHbetas (35-37%) than to higher vertebrate LHbetas (26-30%). The next objective of this work was to compare the development of sturgeon gonads at the very first stages of their growth with the expression of their gonadotropins. Sturgeons at ages 1, 2, 3 or 4 years were sacrificed. The expression of their gonadotropin beta-subunits was determined using quantitative real-time PCR, and their gonads were examined histologically, followed by a determination of the plasma levels of estradiol in females and 11-ketotestosterone (11-KT) in males. The expression levels of stFSHbeta subunit was found to be higher in fish at 3 and 4 years of age than in 1-year olds. mRNA levels of stLHbeta were higher than those of stFSHbeta in both genders. Moreover mRNA levels of stFSHbeta detected in females were significantly higher than those found in males. Even at age 4 years, all female Russian sturgeons tested contained gonads at the pre-vitellogenic stage, with small oocytes and very low levels of estradiol in the plasma. However, among the males, at ages 3 and 4 years, we found testes that contained spermatids and spermatozoa. Those males were found to have significantly high GSI (gonadosomatic index; gonadal weight as a percentage of BW) levels, stLHbeta expression and 11-KT levels.

Amino Acid Sequence↗