共查询到20条相似文献，搜索用时 31 毫秒
1.
T. El-Sayed Ali S. H. Abdel-Aziz A.-F. M. El-Sayed S. Zeid 《Fish physiology and biochemistry》2014,40(5):1495-1507
The present study investigates the effects of different doses (0, 40, 60, 100 μg/L) of 4-nonylphenol (NP) on testis histology and sperms motility of mature Oreochromis niloticus. A tendency for a dose-dependent reduction in the gonado-somatic index (GSI) in the NP-exposed groups was observed. Histological examination revealed that high doses of NP (60 and 100 μg/L) cause hyperplasia of interlobular connective tissue components coincide with decrease in the size of seminiferous lobules and amount of lumen spermatozoa in comparison with the control and low-dose (40 μg/L)-exposed groups. In addition, within the seminiferous lobules, rupture of spermatogenic cysts, vacuolation and necrosis of primary spermatocytes due to damage of sertoli cells were clearly observed and lead to decrease in advanced spermatogenic cells. The highest dose caused significant decrease in the GSI associated with appearance of testis–ova (intersex) state. The percentage of abnormal sperms increased with increasing the dose of NP reaching to 96 % for those subjected to 100 μg NP/L, while it was only 11 % for the control group specimens. The study indicates that NP has estrogenic potency induced marked alteration in the sexual development including inhibition in testicular growth and deformation in the sperms. 相似文献
2.
C.B. Park B.H. Kim O.S. Na Y.B. Song C.H. Lee Y.D. Lee H.J. Baek H.B. Kim 《Fish physiology and biochemistry》2003,28(1-4):441-442
The in vitro effects of bisphenol-A (BPA), nonylphenol (NP) and 4-tert-octylphenol (OP) on vitellogenin (VTG) synthesis were examined using primary cultures of Chinese minnow, Rhynchocypris oxycephalus hepatocytes. In vitro VTG syntheses were induced by exposure to 10?5 M of BPA and 10?4 M of both NP and OP, suggesting that BPA had the highest estrogenic potential among the three phenols. 相似文献
3.
This study evaluates the influence of temperature manipulation on circulating levels of sex steroids and gonadal maturation in F1 generation Senegalese sole Solea senegalensis breeders kept under either continuous light (LL) or natural photoperiod (NP). Under LL, progressive water temperature reduction during early winter [treatment MT (modified temperature)] significantly elevated [compared with exposure to LL and constant temperature (CT)] plasma steroid levels in females (January–February) and males (January) and proportion of females initiating maturation (January), suggesting a modulatory role of decreasing temperature in the early phases of sole gonadal recrudescence. Under NP, treatment MT did not stimulate female gonadal maturation despite the significantly higher plasma testosterone levels (February) compared with exposure to NP and CT, which may indicate that females at early‐intermediate phases of ovarian development, the predominant stages of maturation at early winter, were less responsive to the treatment. Conversely, treatment MT significantly enhanced male androgen production from January onwards, together with an increase in proportions of running individuals (March), indicating that males were also responsive to this treatment at mid‐late phases of testicular development. Our data further support the strong influence of water temperature on the overall control of gonadal maturation in Senegalese sole. 相似文献
4.
In this study, fully vitellogenic oocytes of the longchin goby (Chasmichthys dolichognathus) were exposed to in vitro xenoestrogens such as diethylstilbestrol (DES), bisphenol A (BPA) and nonylphenol (NP) at concentrations of 100 ng/ml in the presence of [3H]17α-hydroxyprogesterone as precursor. The major metabolites produced in vitro are progestogens [17α-hydroxy,20α-dihydroprogesterone (17α20αOHP) and 17α-hydroxy,20β-dihydroprogesterone (17α20βOHP)], androgens [androstenedione (A4) and testosterone (T)] and estrogens [estrone (E1) and estradiol-17β (E2)]. Comparative activities of these chemicals in oocyte steroid biosynthesis showed as follows: NP treatment resulted in clear stimulation of estrogen production, while the opposite occurred in DES treated incubation. Treatment with DES resulted in a higher synthesis of 17α20αOHP. BPA treatment increased the androgen, while estrogen synthesis was slightly inhibited. These results suggest that NP exhibited clearly estrogenic activity on the three chemicals. 相似文献
5.
Ángel García-López Emilio Pascual Carmen Sarasquete Gonzalo Martínez-Rodríguez 《Aquaculture (Amsterdam, Netherlands)》2006,261(2):789-798
A major problem in the development of Senegalese sole Solea senegalensis intensive culture is the poor control on reproduction, in part due to the lack of knowledge on the precise role of photoperiod and temperature. Thus, gonadal maturation was evaluated by assessing the sequential changes in plasma levels of 17β-estradiol (E2), 11-ketotestosterone (11-KT), and testosterone (T) in both female and male cultured Senegalese sole (F1 generation) exposed to various combinations of constant or naturally-fluctuating daylength and water temperature. Under natural photoperiod (NP; 36° N), exposure to constant temperature (t0; 18-20 °C) disrupted gonadal development, as indicated by a lower incidence (in comparison with naturally-fluctuating water temperature; 14-24 °C) of females at advanced maturation (from February to April: 12 vs. 33%) and running males (from February to May: 46% vs. 57%), and the reduced mean (± S.E.M.) sex steroid plasma levels (female peak E2 levels: 2.9 ± 0.28 vs. 1.8 ± 0.3 ng ml− 1; male peak T levels: 1.5 ± 0.14 vs. 0.9 ± 0.06 ng ml− 1). Therefore, the onset and progression of gonadal development in this species seem to be strongly (“proximally”) influenced by fluctuating water temperature. When compared to NP and t0, exposure to continuous light (LL) under t0 significantly reduced steroid production (female peak E2 levels: 1.8 ± 0.28 vs. 0.5 ± 0.05 ng ml− 1; male peak 11-KT levels: 9.4 ± 1.06 vs. 5.4 ± 1.33 ng ml− 1) and subsequently gonadal development (lower proportions of females at intermediate [46 vs. 6%] and advanced maturation [12 vs. 0%] from February to April and of RM [46 vs. 33%] from February to May). Thus, the seasonal changes of daylength would be crucial for normal gonadal development, being its cueing effects of higher magnitude than those of water temperature. The present report constitutes the first systematic study focused on the environmental control of reproductive events in Senegalese sole. 相似文献
6.
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
7.
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
8.
环境雌激素作为一类内分泌干扰物进入人和动物体内后能干扰机体内分泌系统的正常功能,通过多种机制表现出拟天然雌激素或者抗天然雄激素的作用。双酚A（bisphenol A, BPA）和酞酸酯（也称作邻苯二甲酸酯,Phthalic Acid Esters, PAEs）是具有雌激素类活性的环境内分泌干扰物,广泛存在于水环境中,并对水生动物,特别是鱼类的安全造成潜在威胁。本文总结了目前BPA和PAEs对鱼类毒性效应的研究成果,特别是内分泌干扰作用和生殖毒性,为评估这两类环境污染物对鱼类的影响提供参考。 相似文献
9.
Tianqing Huang Huizhi Sun Yanna Wang Gefeng Xu Xingran Wang Ying Han 《Fish physiology and biochemistry》2018,44(1):185-196
Autophagy is a cellular process which occurs in eukaryotic cells. To study the mechanism regulating polyploid fish growth and development is of significance in genetic, because of its growth advantages and economic values. This study focused on triploid female rainbow trout (RBT) which discusses the effects of autophagy on gonadal development of polyploid fish. Autophagy-related genes of RBT lc3b, atg12, atg4b, gabarap1, and bcl2 were cloned, and autophagy gene expressions in gonads were analyzed at different developmental period. Gonadal ultrastructures were observed under transmission electron microscopy. To detect autophagy protein expression and localization, antibodies of RBT-LC3B and RBT-ATG12 were produced. Results showed clear evidence that autophagy-related genes were highly expressed during 200–300 days post fertilization (dpf), in which autophagosome structures were identified. In this stage, the conversion of LC3B-I to LC3B-II was greater than those in other stages. Immunolabeling-manifested autophagy occurred intensively in the cytoplasm of follicular cells. The morphology of follicular cells was gradually changed, leading to gonadal fibrosis and regression. This autophagic research is a new study area on gonadal development of polyploid fish. 相似文献
10.
摘要: 采用组织学和分子生物学方法, 研究了投喂芳香化酶抑制剂来曲唑(LE)后暗纹东方鲀(Takifugu obscures)初孵仔鱼CYP19A、DMRT1基因表达以及性腺的组织学变化, 以期进一步了解P450芳香化酶(P450arom)在鱼类早期性别分化过程中的作用。RT-PCR结果显示, 对照组样品CYP19A和DMRT1表达显示性二态, 雌性表达CYP19A基因, 雄性表达DMRT1基因。LE处理组在性别分化期间, 雄性样品单一表达DMRT1, 雌性样品则同时表达CYP19A和DMRT1。qRT-PCR结果显示: LE处理组雌性仔鱼CYP19A基因表达被显著抑; 虽然在仔鱼出膜后22 d(dph)的表达水平高于9 dph, 但仅为同日对照组的2.11%。LE处理组雌性样品22 dph时DMRT1基因表达量上调, 至150 dph时达对照组雄性水平。55 dph的性腺组织学结果表明, LE处理可导致暗纹东方鲀稚鱼原始卵巢退化, 并向功能性精巢发育。150 dph的LE处理组性腺均为精巢, 并与对照组精巢发育同步。结论认为, 暗纹东方鲀性腺分化期间P450arom是卵巢形成和维持发育所必须的, 抑制P450arom活性可导致雌性暗纹东方鲀发生雄性化逆转。
11.
采用组织学和分子生物学方法,研究了投喂芳香化酶抑制剂来曲唑(LE)后暗纹东方鲀(Takifugu obscures)初孵仔鱼CYP19A、DMRT1基因表达以及性腺的组织学变化,以期进一步了解P450芳香化酶(P450arom)在鱼类早期性别分化过程中的作用。RT-PCR结果显示,对照组样品CYP19A和DMRT1表达显示性二态,雌性表达CYP19A基因,雄性表达DMRT1基因。LE处理组在性别分化期间,雄性样品单一表达DMRT1,雌性样品则同时表达CYP19A和DMRT1。qRT-PCR结果显示:LE处理组雌性仔鱼CYP19A基因表达被显著抑;虽然在仔鱼出膜后22d(dph)的表达水平高于9 dph,但仅为同日对照组的2.11%。LE处理组雌性样品22 dph时DMRT1基因表达量上调,至150 dph时达对照组雄性水平。55 dph的性腺组织学结果表明,LE处理可导致暗纹东方鲀稚鱼原始卵巢退化,并向功能性精巢发育。150 dph的LE处理组性腺均为精巢,并与对照组精巢发育同步。结论认为,暗纹东方鲀性腺分化期间P450arom是卵巢形成和维持发育所必须的,抑制P450arom活性可导致雌性暗纹东方鲀发生雄性化逆转。 相似文献
12.
Comparison of in vitro vitellogenin synthesis among different nonylphenol products using primary cultures of tilapia hepatocytes 总被引：1，自引：0，他引：1
Effect of nonylphenol (NP) products from different companies on in vitro vitellogenin (VTG) synthesis was compared using tilapia ( Oreochromis mossambicus ) hepatocytes cultures. Addition of NP at a concentration of 10−3 M to the medium caused death of hepatocytes (NP-A and NP-B) and delay of monolayer formation (NP-C). No cell death was observed at a concentration of 10−4 M (NP-A, -B and -C) but cell adhesion was slower than control. These results suggest that high concentration of NP is toxic against tilapia hepatocytes. When effects of estradiol-17β (E2 , 10−7 M) and NP (10−4 M) on in vitro VTG synthesis were examined, addition of E2 and NP-A and NP-B to the media resulted in elevation of VTG. NP-C did not induce VTG in the medium. Co-treatment of NP-B and tamoxifen, a non-steroidal anti-estrogen, reduced VTG synthesis. These results suggest that NP has estrogenic potential in primary cultures of tilapia hepatocytes and acts through binding to the estrogen receptor, and that there is a difference in the induction level of VTG among different NP products. 相似文献
13.
14.
研究了辛基酚对鲤的雌激素效应。经10、50、100、300和500μg/L辛基酚暴露32d后,鲤存活率和肥满度与对照组无差异;性腺指数变化明显,雌鱼性腺指数随暴露剂量的增大而增大,雄鱼性腺指数随暴露剂量的增大而减小;50μg/L及以上暴露组与对照组差异显著(P<0.05)。辛基酚能诱导鲤雄鱼产生卵黄蛋白原,暴露剂量为10μg/L组有部分雄鱼肝脏匀浆和血液中检出卵黄蛋白原,50、100和300μg/L组卵黄蛋白原含量随辛基酚浓度的增大而显著增大,500μg/L组卵黄蛋白原含量低于300μg/L组、高于100μg/L组,均为极显著差异(P<0.01)。 相似文献
15.
Ganesan Nagarajan Adimoolam Aruna Ching-Fong Chang 《Fish physiology and biochemistry》2013,39(1):95-101
Despite neurosteroidogenic enzymes are playing important roles in the regulation of brain development and function, the potential link between brain and gonad by the action of steroid hormones during gonadal sex differentiation is still not clear in teleosts. In this mini-review, we summarized our understanding on the early brain development related to the synthesis of neurosteroids and receptor signaling during gonadal sex differentiation in protogynous orange-spotted grouper, Epinephelus coioides (functional females for the first 6 years of life and start to sex change around the age of 7 years) and protandrous black porgy (functional males for the first 2 years of life but begin to change sex during the third year). We found a similar profile in the increased expression of brain aromatase gene (aromatatse B or cyp19a1b), aromatase activity, estradiol (E2), and estrogen signaling in the brain of both grouper and black porgy fish during gonadal sex differentiation. In contrast to mammals, teleost fish Cyp19a1b expressed in a unique cell type, a radial glial cell, which is acted as progenitors in the brain of developing and adult fish. In agreement with these pioneer studies, we demonstrated that the grouper cyp19a1b/Cyp19a1b was expressed in radial glial cells. Further, in vivo data in the grouper brain showed that exogenous E2 upregulated Cyp19a1b immunoreactivity (ir) in radial glial cells. These data suggest the possible roles of Cyp19a1b and E2 in early brain development which is presumably related to gonadal sex differentiation. 相似文献
16.
Huayu Song Mengxun Wang Zhongkai Wang Jinxiang Liu Jie Qi Quanqi Zhang 《Fish physiology and biochemistry》2017,43(3):731-753
Reproduction allows organisms to produce offspring. Animals shift from immature juveniles into mature adults and become capable of sexual reproduction during puberty, which culminates in the first spermiation and sperm hydration or ovulation. Reproduction is closely related to the precise control of the hypothalamic–pituitary–gonadal (HPG) axis. Kisspeptin peptides are considered as the important regulator of HPG axis in mammalian. However, the current understanding of kisspeptin in flatfish is not comprehensive. In this study, we cloned and analyzed the kiss2 and kissr2 genes in Cynoglossus semilaevis. Interesting alternative splicing in the 5′-untranslated regions (UTR) of the Cskissr2 gene was found. The expression profiles of Cskiss2 and Cskissr2 showed relative high messenger RNA (mRNA) levels at the late gastrula stage during embryonic development, at total length = 40 mm during early gonadal differentiation, and in the brains and gonads of all investigated tissues. These results suggested that the kisspeptin system participated in embryogenesis and in the regulation of gonadal differentiation and development. Considering that the control and regulatory mechanisms of kisspeptin in the central reproductive axis are still unclear, we documented that the intramuscular injection of kisspeptin caused different sGnRH and cGnRH mRNA levels in a dose- and tissue-dependent manner. The mRNA expressions of FSH and LH were stimulated in the ovary and were inhibited in the testis under the kisspeptin treatments. These results provided foundations for understanding the roles of kisspeptin in the neuroendocrine system in fish. The manipulation of the kisspeptin system may provide new opportunities to control the gonadal development and even reproduction in fish. 相似文献
17.
The photoreceptors regulating photoperiodic gonadal development of ayu, Plecoglossus altivelis, are not known. In this study, we examined whether the gonads of ophthalmectomized and pinealectomized (Ex+Px) ayu respond to short photoperiod. Gonadosomatic index (GSI) and plasma levels of sex steroids were significantly increased in Ex+Px ayu kept under short photoperiod in both males and females. On the other hand, there were no significant increase in GSI and sex steroids in Ex+Px ayu kept under long photoperiod. The histological observation of the gonads revealed that oocytes undergoing final maturation in females and proliferation of germ cells in males were observed only in Ex+Px ayu kept under short photoperiod. Altogether, our results strongly suggest unknown photoreceptive organ regulates photoperiodic gonadal development of ayu. 相似文献
18.
A specific immunoassay was developed for the quantification of testosterone (T) in sea bass plasma. Specific primary antibody against T was produced using an antigen BSA conjugated with T. The enzyme immunoassay (EIA) had a sensitivity of 5–0.009 ng ml–1 and 6.2% intra-assay variation; inter-assay variation was 9.5% for sea bass plasma. The effects of two different accelerating photoperiod regimes, compressed photoperiod (CO; 6 months), and constant short photoperiod (9L:15D) with a long photoperiod (15L:9D) in March (SLmar), on T plasma levels and sexual maturation were examined during the onset of puberty in male sea bass. Natural photoperiod (NP) and SLmar groups exhibited the highest T values in December (8.69±1.03 and 10.85±1.04 ng ml–1, respectively). However, SLmar group showed the first significant decrease in T plasma levels in January, two months earlier than the NP group, which presented elevated T levels until February. The CO group displayed two significant T peaks, one in October (8.90±1.60 ng ml–1) and the other in January (9.60±1.10 ng ml–1). Gonadosomatic index (GSI) in the NP and SLmar groups displayed the highest values from December to February (>2.5%). However, the SLmar group showed the first significant increase in GSI in November, one month before the controls, indicating a clear advancement of gonadal development with respect to the NP group. In the CO group, a bimodal pattern was observed with two peaks, one in October–November (1.30±0.25%) and the second in March–April (0.97±0.33%) (P<0.05). In NP group, the percentage of running males was about 80% from December to March while the percentage of running males in the SLmar group (70%) lasted only three months (December to February) decreasing (P<0.05) in March. In the CO group, spermiation began in October (60%), decreased during the next months, and increased again in March–April (30%) (P<0.05). These results indicate the advancement of puberty by either one or two months with respect to the control group in the SLmar and CO groups, respectively, and the presence of a second reproductive surge in the CO group. Collectively, these results suggest that exposure of fish to these photoperiod regimes may affect both the time of the onset of puberty and the pattern of gonadal development in prepuberal male sea bass. 相似文献
19.
Martín Blasco Gustavo Manuel Somoza Denise Vizziano-Cantonnet 《Fish physiology and biochemistry》2013,39(1):71-74
The involvement of androgens during sex differentiation period was investigated in the pejerrey Odontesthes bonariensis, by classic biochemical studies and gonadal histology. We studied in particular whether the enzyme activities involved in 11-oxygenated androgen production were active in a gonadal/peritoneum complex (GPC) of very small larvae exposed to masculinizing temperatures previous to morphological sex differentiation (5 weeks post-hatching). The GPC was incubated with 17-hydroxyprogesterone (3H-17P), and the presence of 11-KT as major metabolite in early gonads undergoing masculine pathway after temperature treatment exposure is reported. 11-KT was identified by thin-layer chromatography and high-pressure liquid chromatography. The present results show that 11-KT is produced at very early stages of testis development in pejerrey, being this androgen one of the main mediators of the masculinization induced by temperature treatment at the gonad level. 相似文献
20.
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