共查询到20条相似文献，搜索用时 156 毫秒
1.
Wei Ge Nga-Ling Ko Flora Yee-Man Pang Me-Fong Chung Sze-Wah Lin Chi-Wai Yuen Man-Tat Lau Lin Liu Young Chang Sohn Makito Kobayashi Katsumi Aida 《Fish physiology and biochemistry》2003,28(1-4):65-71
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play critical roles in controlling vertebrate gonadal development and function. Activin, a dimeric growth factor initially identified in the gonads, is important in the differential regulation of the two gonadotropins in mammals. Using goldfish as a model, we have demonstrated that activin stimulates FSHβ but suppresses LHβ expression. The present study demonstrated that the 5′-flanking region of goldfish FSHβ gene is functional in the mouse gonadotrope cell line, LβT2 cells. Similar to its effect on the cultured pituitary cells, activin stimulated FSHβ promoter activity in the LβT2 cells and the effect could be blocked by its binding protein follistatin. Follistatin also significantly suppressed the basal FSHβ promoter activity, suggesting secretion of endogenous activin by the LβT2 cells. Further characterization of the cis-regulatory elements responsible for activin stimulation is now under way in our laboratory. 相似文献
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A. H. M. M. Reza S. F. Rakhi M. S. Hossen K. Takahashi Z. Hossain 《Fish physiology and biochemistry》2013,39(4):779-791
Incorporation of polyunsaturated fatty acids (PUFAs) as biofunctional compounds with feed is an effective way for gonadal maturation without any hazardous effects on animal health, and thus it is possible to save the vulnerable species from the danger of extinction. In the present study sperm quality, level of Ca2+ concentration in serum, histological structure of the liver and developmental stages of ovary of an endangered fish species, Nandus nandus were investigated for the confirmation of the positive effects of PUFAs in reproduction and gonadal maturation. Fishes were collected from Brahmaputra River, Mymensingh, Bangladesh. Treated group was fed 1 % squid extracted phospholipid supplemented diet that was mixed with silver carp fish muscle where as controlled group was fed the same except phospholipid. For histology of liver and gonads, samples were dehydrated, cleaned and infiltrated, embedded in paraffin wax and sectioned. After that, the samples were stained with hematoxylin and eosin. The photomicrographs of the stained samples were taken by using light microscope. In comparison with the control group, treated group exhibited higher gonadal maturation which resulted in spontaneous spawning. Treated female demonstrated advanced gonadal developmental stages in comparison with the controlled female during different months. During spawning season, lipid granules and normal morphological alteration were observed in case of treated fish liver, whereas less lipid granules with more histological alteration of liver were observed in control group. Serum Ca2+ concentration in treated female was found significantly higher (P < 0.01) in contrast to the controlled female during the breeding season which was an indicator of the augment of estrogen secretion during ovarian maturation. Better sperm quality, early maturation of oocytes, less histological alteration of liver hepatocytes and spontaneous spawning performances of PUFA-treated fish were as a result of the efficiency of PUFAs in enhancing maturation. The experiment suggests that supplementation of dietary PUFAs improve the spawning performances of fish. 相似文献
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Koichiro Gen Sonoko Yamaguchi Koichi Okuzawa Naoki Kumakura Hideki Tanaka Hirohiko Kagawa 《Fish physiology and biochemistry》2003,28(1-4):77-80
The duality of gonadotropins (GTHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), has been confirmed in most teleost species, but very little is known about their biological functions. To elucidate the physiological roles of FSH and LH in fish reproduction, the expression profiles of GTH subunit genes during gonadal development were analyzed in both male and female red seabream. Furthermore, in vitro studies were carried out to examine the effects of GTHs on steroid hormone production and cytochrome P450 aromatase (P450arom) expression in red seabream gonads. In both sexes, LHβ mRNA was maintained at high levels from the early gametogenesis until spawning season, and declined with gonadal regression. Interestingly, FSHβ mRNA levels in males increased in parallel with testicular development, whereas those in female were remained low throughout oocyte development. From in vitro studies using purified red seabream FSH and LH, both GTHs had a similar potency in stimulating 11-ketotestosterone production by testicular slices, while the biological activity of FSH was much lower than that of LH in stimulating production of estradiol-17β by vitellogenic follicles. Moreover, expression of P450arom mRNA was induced by LH, but not FSH, in ovarian follicles in vitro. FSH was also ineffective in inducing maturational competence and final oocyte maturation. These results suggest that, unlike salmonids, FSH may play an important role during gametogenesis in male, but not female, red seabream, whereas LH may be involved in regulation of both early and late gametogenesis in both sexes. 相似文献
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M. Kobayashi T. Morita K. Ikeguchi G. Yoshizaki T. Suzuki S. Watabe 《Fish physiology and biochemistry》2003,28(1-4):469-471
Recombinant gonadotropins (GTH), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) of goldfish Carassius auratus were produced by baculovirus in silkworm larvae. Hemolymph containing recombinant FSH (rFSH) or LH (rLH) was collected from silkworm larvae, and its biological activity was examined in vivo using male goldfish and female bitterling Rhodeus ocellatus ocellatus. Injection of hemolymph containing rFSH or rLH induced milt production in male goldfish, whereas only rLH induced ovulation in female bitterling. These results suggest, that biologically active goldfish recombinant GTH could be applied for the induction of gonadal development in aquaculture fishes as a substitute of pituitary extract, if a method of large scale production is established. 相似文献
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The roles of salmon GnRH (sGnRH) and gonadal steroid hormones in regulation of LH synthesis and release were examined in primary pituitary cell cultures of masu salmon (Oncorhynchus masou). Pituitaries were taken from fish at four reproductive stages: in March (initiation of sexual maturation); May (early maturation); July (pre-spawning); and September (spawning period). Amounts of LHβ subunit mRNA in the pituitary cells were determined by real-time PCR, and LH levels in the medium were determined by RIA. sGnRH and gonadal steroids including estradiol-17β (E2), testosterone (T) and 11-ketotestosterone (11-KT) were added to the cultures to examine their direct effects on LH response. sGnRH had no significant effect on LHβ mRNA levels at any stages, although a stimulatory trend was noted in March. In contrast, E2 and T considerably increased LHβ subunit mRNA levels in March and May during initial stages of maturation, and the effects were less pronounced in July and September. On the other hand, sGnRH stimulated LH release at all stages in the males and the effects were most prominent in July and September. E2 and T also stimulated LH release in July and September, but their effects were weaker than that of sGnRH. The present results indicate that sGnRH and gonadal steroids directly regulate LH synthesis and release in masu salmon pituitary cells: sGnRH mainly stimulates LH release in the late stage of sexual maturation; whereas, E2 and T are effective in stimulating LH synthesis at earlier stages of maturation. 相似文献
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Gilberto Grandi Maria Gabriella Marchetti Mattia Lanzoni Milvia Chicca 《Fish physiology and biochemistry》2014,40(4):1115-1139
The adenohypophysis was studied by immunocytochemical and ultrastructural methods in juvenile grass carp (Ctenopharyngodon idella) from natural reproduction in Northern Italian rivers. The adenohypophysis included the rostral pars distalis (RPD), the proximal pars distalis (PPD) and the pars intermedia (PI), all deeply penetrated by branches of the neurohypophysis (Nh). The prolactin (PRL), adrenocorticotropic (ACTH), somatotropic (GH), thyrotropic (TSH), gonadotropic type I (GtH I) and type II (GtH II), somatolactin (SL), melanotropic (MSH) and endorphin (END) cells were identified with antisera raised against piscine and human pituitary hormones. In juveniles of 51–69 mm of total body length (TL) with undifferentiated gonads, the PRL cells, arranged in thick strands, occupied most of the RPD. The ACTH and GH cells organized in cords bordering Nh were, respectively, confined to RPD and PPD. The TSH cells were scattered among ACTH cells in RPD and among GH cells in PPD. Cells simultaneously immunoreactive to anti-follicle stimulating hormone and to anti-croaker gonadotropin were intermingled among GH and TSH cells, which were mostly in the dorsal PPD. The SL cells were detected in PI layers bordering the Nh. The MSH and END cells were intermingled in PI and, unlike what observed in other teleosts, their respective antisera did not cross-react. In individuals of 78–112 mm TL with gonads at the beginning of differentiation, the GtH II cells were detected in PPD; all other cell types increased in number. These results, supported by ultrastructural investigations, suggest that SL and GtH II cells are directly involved in gonadal differentiation in C. idella. 相似文献
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Wei Wang Hua Zhu Ying Dong ZhaoHui Tian Tian Dong HongXia Hu CuiJuan Niu 《Fish physiology and biochemistry》2017,43(6):1557-1569
Molecular mechanism of sex determination and differentiation of sturgeon, a primitive fish species, is extraordinarily important due to the valuable caviar; however, it is still poorly known. The present work aimed to identify the major genes involved in regulating gonadal development of sterlet, a small species of sturgeon, from 13 candidate genes which have been shown to relate to gonadal differentiation and development in other teleost fish. The sex and gonadal development of sterlets were determined by histological observation and levels of sex steroids testosterone (T), 11-ketotestosterone (11-KT), and 17β-estradiol (E2) in serum. Sexually dimorphic gene expressions were investigated. The results revealed that gonadal development were asynchronous in 2-year-old male and female sterlets with the testes in early or mid-spermatogenesis and the ovaries in chromatin nucleolus stage or perinucleolus stage, respectively. The levels of T and E2 were not significantly different between sexes or different gonadal development stages while 11-KT had the higher level in mid-spermatogenesis testis stage. In all the investigated gonadal development stages, gene dmrt1 and hsd11b2 were expressed higher in male whereas foxl2 and cyp19a1 were expressed higher in female. Thus, these genes provided the promising markers for sex identification of sterlet. It was unexpected that dkk1 and dax1 had significantly higher expression in ovarian perinucleolus stage than in ovarian chromatin nucleolus stage and in the testis, suggesting that these two genes had more correlation with ovarian development than with the testis, contrary to the previous reports in other vertebrates. Testicular development-related genes (gsdf and amh) and estrogen receptor genes (era and erb) differentially expressed at different testis or ovary development stages, but their expressions were not absolutely significantly different in male and female, depending on the gonadal development stage. Expression of androgen receptor gene ar or rspo, which was supposed to be related to ovarian development, presented no difference between gonadal development stages investigated in this study whenever in male or female. 相似文献
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To assess the response of the GtH system to the removal of gonadal feedback, effects of bilateral gonadectomy and 17β-estradiol (E2) replacement on gonadotropin (GtH) subunit expression, as well as LH protein levels, were monitored in the pituitary. Adult female hybrid striped bass undergoing mid-vitellogenesis were divided into one sham and two gonadectomized (gdx) groups. One gdx group received E2 (2 mg kg?1) via microspheric delivery systems, the other was given a vehicle injection. Groups were sampled on days 3 and 14 post-surgery (PS). Expression of all GtH subunits was significantly increased in the gdx group on both days compared to the shams, whereas E2 replacement in gdx fish restored alpha and LHβ mRNA levels to those of the sham fish and dramatically reduced FSHβ mRNA levels. Gdx had no effect on the pituitary concentration of LH. E2 replacement, however, reduced protein levels significantly on day 3, but not day 14. In conclusion, during mid-vitellogenesis expression of both GtHβ subunits is negatively controlled by gonadal feedback, which is also evident by restoration of gdx subunit mRNA levels to those of the shams after E2 replacement. 相似文献
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Rafael Henrique Nóbrega Lázaro Wender Oliveira de Jesus Renato Massaaki Honji Maria Inês Borella 《Fish physiology and biochemistry》2017,43(1):51-63
This work describes gonadotropic (GtH) cells and their morphological and immunohistochemical changes during the spermatogenic cycle of Serrasalmus maculatus (continuous spermatogenesis) and Pimelodus maculatus (seasonal spermatogenesis). GtH cells, widely distributed in the proximal pars distalis of the adenohypophysis, were characterized as round-shaped cells with eccentric nucleus, and cytoplasm with basophilic secretory granules and a variable number of vacuoles for both species. Immunohistochemistry against β-follicle-stimulating hormone (Fsh) and β-luteinizing hormone (Lh) in adjacent sections showed two separated GtH-producing cell populations, and a third population where both GtHs are expressed in the same cell for both species. In the seasonal spermatogenesis of P. maculatus, GtH cells seemed to be more abundant during developing and spawning capable phases. In contrast, no cyclic changes were detected in the continuous spermatogenesis of S. maculatus, except for the strong immunoreaction for Fsh and Lh in males with intense spermiogenesis. We conclude that changes reported here might reflect the type of spermatogenic cycle (seasonal or continuous) which are under different regulatory mechanisms (environmental and internal cues) controlling the reproduction in these species. 相似文献
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Violeta da Rocha Perini Alessandro Loureiro Paschoalini Cláudia Kelly Fernandes da Cruz Rita de Cássia Gimenes Alcântara de Rocha José Augusto Senhorini Dirceu Marzulo Ribeiro Paulo Sérgio Formagio Nilo Bazzoli Elizete Rizzo 《Fish physiology and biochemistry》2013,39(6):1473-1484
This study investigated for the first time the reproductive biology of Prochilodus lineatus in a system of rivers in southeastern Brasil, relating it to the role of tributary rivers in the reproductive success of this important commercial fish in the Upper Paraná River basin, where a cascade of hydroelectric dams were deployed. Specimens were caught bimonthly in three river sites: (S1) Grande River, downstream from the Porto Colômbia dam; (S2) Pardo River; and (S3) Mogi Guaçu River. Sex steroid plasma levels, fecundity, follicular atresia, oocyte diameter and gonadosomatic index (GSI) were compared among sites. In S1, fish exhibited changes in the reproductive parameters: lower GSI, oocyte diameter and fecundity and higher follicular atresia index, when compared to S2 and S3. Frequency of maturing fish was higher in S3 and spawning was only registered in S3. In sites S2 and S3, plasma concentrations of testosterone and 17β-estradiol in females and testosterone in males showed wide variations following gonadal maturation. Fish from S1 showed few significant variations in sex steroid concentrations throughout the gonadal cycle. These results indicate that P. lineatus does not reproduce in Grande River (S1), but probably uses the Pardo River (S2) as a migratory route towards the Mogi Guaçu River (S3) where they complete gonadal maturation and spawning. Our findings contribute for understanding the reproductive biology of P. lineatus and to highlight the importance of tributaries in impounded rivers as a favourable environment for migration and spawning of fish. 相似文献
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Inés Martínez-Pita Clara Sánchez-Lazo Marcelino Herrera 《Aquaculture International》2016,24(5):1247-1254
The concentration of the sex steroids 17β-estradiol, testosterone and progesterone was determined by specific enzyme-linked immunosorbent assays in the hemolymph of the mussel Mytilus galloprovincialis and related to its sexual maturation. A non-lethal hemolymph sampling procedure was used in mussels matured in controlled conditions of a hatchery. To our knowledge, this is the first study on sexual steroid hormones of a bivalve species using the same specimens in consecutive samplings. Histological data showed that nearly 90 % of the mussels ripened during the experiment. Steroid analyses revealed that 17β-estradiol and testosterone were closely related to the onset of gamete development, while progesterone would have an important role at the end of gonadal maturity. This method can be used to assess sexual maturation in bivalves when conditioning in hatcheries, without killing them. 相似文献
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Two distinct gonadotrophs, FSH cells and LH cells, were identified in the pituitaries of various perciform fishes using immunocytochemistry with antisera raised against synthetic fragment peptides of mummichog FSHβ and LHβ. Considerable variation in the roles of FSH among species was inferred from the extensive diversity in the abundance of FSH cells. 相似文献
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The effects of different temperature on gonadal development of Periophthalmus modestus were examined by histological and endocrinological analyses. Results showed that vitellogenesis and spermatogenesis were induced by high temperature treatment (30 °C). While, gonadal development did not occur in the low temperature treatment (18 °C). These results suggest that a rise in temperature plays an important role in gonadal development of this fish. 相似文献
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SOX9基因在脊椎动物性别决定和性腺分化中扮演重要的调控作用。从mRNA和蛋白水平分析中华鳖SOX9基因在不同组织中的差异性表达、在胚胎性腺和成年睾丸中的细胞定位以及在性逆转中的表达变化,研究SOX9基因在中华鳖性别分化中的调控作用。Real-time PCR结果显示,SOX9基因在中华鳖雄性性腺中特异性表达。免疫荧光染色分析显示,SOX9蛋白在雄性18期胚胎性腺中开始表达,随着性腺的发育,SOX9蛋白定位于性腺Sertoli前体细胞细胞核中;而在雌性胚胎性腺并未见其表达。此外,在雌激素诱导的雄性向雌性性逆转胚胎中,SOX9基因显著下调,而在芳香化酶抑制剂诱导的雌性向雄性性逆转胚胎中,SOX9基因表达则显著上升。研究表明,SOX9基因为中华鳖雄性特异性基因,参与雄性性腺的发育过程,可能在中华鳖早期性别分化过程中起调控作用。 相似文献
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T. Kobayashi H. Kajiura-Kobayashi Y. Nagahama 《Fish physiology and biochemistry》2003,28(1-4):157-157
We reported previously that two isoforms of vasa mRNA and protein are present in tilapia (Kobayashi et al. 2002). One (vas-s) lacks a part of the N-terminal region found in the other isoform (vas). Both isoforms are expressed in oocytes through the embryonic stages when PGCs localize in the lateral plate mesoderm. After PGCs localized in the gonadal anlagen, vas-s expression increased and vas expression became undetectable. Expression of both isoforms was observed again after morphological gonadal sex differentiation, irrespective of genotypic sexes. These changes are in accordance with sex differences in number of gonial germ cells during this period, suggesting that molecular sexual dimorphism occurs in germ cells between both sexes during this period. 相似文献