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Spotted scat Scatophagus argus exhibits a typical sexual growth dimorphism in which the females grow faster than the males. Growth hormone (GH) is best known as an anterior pituitary hormone fundamental in regulating growth. To clarify the roles in sexual growth dimorphism in the spotted scat, gh cDNA was isolated from the pituitary. A phylogenetic tree was constructed based on the GH amino acid sequences of spotted scat and other vertebrates, and the resulting topology clearly reflects the taxonomic relationship of the Perciformes species selected. Alignment of GH amino acid sequences displayed very high similarity between the spotted scat and the other Perciformes species. The qRT-PCR analysis demonstrated that females exhibited higher pituitary gh mRNA levels than males at 6, 18, and 30 months (P < 0.05), which was 1.84, 4.61 and 6.34 times greater, respectively. In addition, immature males (6 months) exhibited higher pituitary gh mRNA levels than mature males (18 and 30 months). These results imply that the sexual growth dimorphism may be ascribable to the gh levels in pituitary in spotted scat. 相似文献
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Anderson O. L. Wong John P. Chang Richard E. Peter 《Fish physiology and biochemistry》1993,11(1-6):77-84
In vivo and in vitro approaches have been used to examine the role of dopamine (DA) as a growth hormone (GH)-releasing factor in the goldfish. DA stimulated GH release from perifused pituitary fragments of goldfish in a dose-dependent manner. The GH-releasing effect of DA was seasonal, being the highest in sexually regressed fish, intermediate in recrudescent fish, and the lowest in sexually mature (prespawning) fish. The GH response to DA was blocked by the D1 antagonist (+)SCH23390, confirming the involvement of D1 receptors in DA-stimulated GH release. In studies using static incubation of pituitary cells, somatostatin, a known physiological GH-release inhibitor in the goldfish, abolished the GH response to DA. Intraperitoneal injection of apomorphine, a non-selective DA agonist, also increased the plasma GH levels and enhanced the linear body growth of goldfish. These results strongly suggest that DA, by acting through DA D1 receptors, functions as a GH-releasing factor in the goldfish. 相似文献
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In vivo andin vitro techniques were used to examine the influence of various vertebrate peptides on growth hormone (GH) secretion in the goldfish.
Tetradecapeptide somatostatin (SRIF-14) was found to inhibit GH secretionin vitro from perifused pituitary fragments, whereas similar concentrations of a salmonid SRIF peptide (sSRIF-25) did not affect GH
secretion from the goldfish pituitary fragments. This indicates that SRIF receptors on the goldfish pituitary are very specific
for SRIF-14-like peptides. Salmon gonadotropin (GTH)-releasing hormone (sGnRH) was found to elevate serum GH levels in male
goldfish. The dopamine antagonist pimozide alone or injected in combination with sGnRH did not influence serum GH levels,
although injection of pimozide alone significantly elevated serum GTH levels, in addition to potentiating the effects of sGnRH
on GTH secretion. sGnRH stimulated GH secretion from goldfish pituitary fragmentsin vitro, indicating that sGnRH acts directly at the level of the pituitary to stimulate GH secretion in the goldfish. These results
suggest that GnRH may also function as a GH-releasing factor in the goldfish, although the release-inhibitory factors for
GH and GTH secretion do appear to be separate and distinct. Two human GH-releasing hormone (hGHRH) peptides were found to
be ineffective in altering GH secretionin vitro from the perifused pituitary fragments. Consequently, a role for a mammalian GHRH-like peptide in the hypothalamic regulation
of GH secretion in the goldfish remains questionable. 相似文献
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Novel droplet vitrification combined with fish antifreeze protein type III enhances cryoprotection of semen in wild endangered Persian sturgeon Acipenser persicus (Borodin, 1897) 
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下载免费PDF全文 Amirreza Abed‐Elmdoust Hamid Farahmand Bagher Mojazi‐Amiri Gholamreza Rafiee Ruhollah Rahimi 《Aquaculture Research》2015,46(10):2392-2397
In this study, the efficiency of a novel droplet vitrification technique along with different doses of fish antifreeze protein (AFP) type III on Persian sturgeon thawed spermatozoa quality (motility duration and motility percentage) was investigated. Semen of seven male individuals was pooled in equal volumes and diluted with 4°C Tris‐Hcl (100 mM), pH = 8 extenders containing 0, 5, 10, 15 μM of AFP type III in a ratio of 1:1 (semen/extenders). Treated semen was dropped into liquid nitrogen. Solidified droplets were stored for 2, 60 and 120 days and thawed by plunging them into a tube containing 5 mL Tris‐Hcl (100 mM), pH=8 with 1% BSA at 37°C. Motility duration in all treatments had no significant difference comparing to fresh sperm (P > 0.05), but their motility percentage was significantly lower. Treatment with 10 μM of AFP had significantly higher motility percentage (16.11 ± 0.5%) comparing to other treatments (P < 0.05). There was no significant difference between 0, 5, 15 μM of antifreeze protein treatments (P > 0.05), suggesting that antifreeze protein effectiveness are highly dose dependent, and dose of 10 μM is appropriate in Persian sturgeon spermatozoa droplet vitrification. Besides, the present technique obtained higher quality of spermatozoa comparing to its analogue techniques. 相似文献
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J.N. Nocillado H.K. Chua E. O'Brien K. Guyatt F. Carrick A. Elizur 《Fish physiology and biochemistry》2003,28(1-4):47-48
The cDNAs coding for the brain GnRHs (AY373449-51), pituitary GH, SL and PRL, and liver IGFs (AY427954-5) were isolated. Partial cDNA sequences of the brain (Cyp19b) and gonadal (Cyp19a) aromatases have also been obtained. These tools would be utilized to study the endocrine regulation of puberty in the grey mullet. 相似文献
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Growth hormone (GH) secretion from organ-cultured pituitaries of the eel (Anguilla japonica) was studied during incubation in a defined medium for 2 weeks, using a homologous radioimmunoassay which does not distinguish
between the two molecular forms of eel GH. The total amount of GH secreted increased gradually during the incubation period;
so that the amount of GH released on day 14 was about 30 times greater than that on day 1. On day 14, the proportion of GH
released relative to the total amount of GH present (the sum of GH released into the medium and residual content in the pituitary)
was 96% and the amount produced on day 14 was 4 times greater than the content in the unincubated pituitary. Somatostatin
(SRIF, 1.8 × 10-7 M) inhibited the increase in GH release. On day 7, the proportion of GH released by pituitaries treated with SRIF (28%) was
less than that released by the control pituitary (91%). There was no significant difference in GH release between the pituitaries
incubated in isotonic medium (300 mOsm) and those in hypotonic medium (240 mOsm) for 2 weeks except for the first 3 days,
when the pituitaries in hypotonic medium secreted significantly greater amounts of GH than those incubated under isotonic
condition. Hypertonic medium (350 mOsm) had no effect on GH release except for significant inhibition on days 6 and 14. When
secretion of the two forms of GH (GH I and II) was examined after separation by polyacrylamide gel electrophoresis followed
by densitometry, slightly more GH I tended to be secreted than GH II during the culture period, although the effects of SRIF
and osmolality of the media on GH I release were similar to those on GH II. It is concluded that GH secretion and production
in the eel is mainly under the inhibitory control of hypothalamus, and that osmolality has a minimum influence on the GH release. 相似文献
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A.O.L. Wong C.K. Murphy J.P. Chang C.M. Neumann A. Lo R.E. Peter 《Fish physiology and biochemistry》1998,19(1):23-34
In this study, the direct actions of serotonin (5HT) on gonadotropin (GTH)-II and growth hormone (GH) release in the goldfish were tested at the pituitary cell level. 5HT (10 nM - 10 µM) stimulated GTH-II but inhibited GH release from perifused goldfish pituitary cells in a dose-dependent manner. The minimal effective dose of 5HT tested to suppress basal GH secretion (10 nM) was 10-fold lower than that to stimulate GTH-II release (100 nM). The GTH-II releasing effect of 5HT was abolished by repeated 5HT treatment (10 µM) whereas the corresponding inhibition on GH release was unaffected. These results suggest that 5HT receptors on goldfish gonadotrophs and somatotrophs exhibit intrinsic differences in terms of sensitivity to stimulation and resistance to desensitization. Salmon GTH-releasing hormone (sGnRH, 100 nM) stimulated GTH-II and GH release from goldfish pituitary cells. The GTH-II releasing action of sGnRH was unaffected by simultaneous treatment of 5HT (1 µM). However, the corresponding GH response to sGnRH (100 nM) was inhibited. In the goldfish, dopamine is known to stimulate GH release through activation of pituitary D1 receptors. In the present study, the GH-releasing action of dopamine (1 µM) and the D1 agonist SKF38393 (1 µM) was significantly reduced by 5HT (1 µM). To examine the receptor specificity of 5HT action, the effects of 5HT1 and 5HT2 analogs on GTH-II and GH release were tested in goldfish pituitary cells. The 5HT1 agonist 8OH DPAT (0.1 and 1µM) and 5HT2 agonist methyl 5HT (0.1 1µM) mimicked the GTH-II releasing effect of 5HT. The 5HT1 agonist 8OH DPAT (0.1 and 1µM) also stimulated GH release but the 5HT2 agonist methyl 5HT (0.1 and 1µM) was inhibitory to basal GH secretion. In addition, 5HT (1µM) -stimulated GTH-II release was abolished by the 5HT1 antagonist methiothepin (10µM) and 5HT2 antagonist mianserin (10µM). Similarly, the inhibitory action of 5HT (1µM) on basal GH release was blocked by the 5HT2 antagonist mianserin (10µM). The 5HT1 antagonist methiothepin (10µM) was not effective in this regard. These results, taken together, indicate that 5HT exerts its regulatory actions on GTH-II and GH release in the goldfish directly at the pituitary cell level, probably through interactions with other regulators including sGnRH and dopamine. The GTH-II releasing action of 5HT is mediated through 5HT2 and possibly 5HT1 receptors. The inhibition of 5HT on basal GH release is mediated through 5HT2 receptors only. Apparently, 5HT1 receptors are not involved in this inhibitory action. In this study, a paradoxical stimulatory component of 5HT on GH release by activating 5HT1 receptors is also implicated. 相似文献
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The glutamate agonist, N-methyl-D,L-aspartate (NMA) stimulates the secretion of growth hormone (GH) from pituitary fragments
in vitro and increases plasma GH levels in vivo in rainbow trout, Oncorhynchus mykiss (Flett et al. 1994; Holloway and Leatherland
1997a,b); however gonadal steroid hormones appear to modulate this response in experimental situations. This study examines
whether steroid hormones also modulate the GH-regulatory actions of NMA during the normal reproductive cycle of rainbow trout
by examining the relationship between the stage of sexual maturation and the pituitary release of GH in vitro in response
to an NMA (10-8 M) challenge. NMA had no effect on mean GH release from the pituitary glands of fish that were immature (GSI <1.0), from
males during early development (GSI 1.0-3.0), or from sexually mature males (with free running milt) and females (ovulated).
However, NMA significantly increased GH release from pituitary glands taken from females during the early stages of gonadal
growth (GSI 1.0-9.0) and from males and females sampled during the later stages of gonadal growth (males GSI 3.01-6.0; females
GSI 9.01-15.0). The GH-stimulatory action of NMA in males and females progressed to a maximum effect during the late stages
of gonadal growth, and disappeared in ovulated females and free running males. Moreover, in female fish, the maximal GH release
in response to the NMA challenge is positively correlated with plasma 17β-estradiol levels; no such correlation was evident
for plasma testosterone levels in males. Changes in the GH response to NMA during maturation while gonadal steroid levels
fluctuate provides further evidence to suggest that the effects of NMA on GH secretion are intimately linked to endogenous
gonadal steroid hormone levels.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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In saffron cod, Eleginus gracilis, the antifreeze glycoprotein (AFGP) is present during the winter. The effects of salmon prolactin (sPRL) and growth hormone (sGH) on plasma osmolality, sodium concentration and protein content of the saffron cod were investigated. In the winter, plasma osmolality and protein content decreased following the intraperitoneal injection of sPRL (20 µg kg-1 day-1 × 3) but injection of the same dose of sGH had no effect on either plasma osmolality or protein content. In similar experiments performed during the summer, sPRL and sGH had no effect on these parameters. The results suggest that PRL may act on the kidney, possibly clearing antifreeze glycoprotein (AFGP) by increasing glomerular filtration. The possible role of PRL and GH in the disappearance of AFGP during the summer are discussed. 相似文献
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大鳍鳠脑垂体和血清生长激素水平的季节变化 总被引：4，自引：0，他引：4
根据大鳍脑垂体匀浆和血清样品的稀释曲线与鲤生长激素（ｃＧＨ）标准曲线的平行性,采用鲤生长激素的标准品和抗血清（ＲＡＧ）测定了周年中几个不同时期大鳍脑垂体和血清样品的生长激素（ＧＨ）含量,发现脑垂体和血清中的ＧＨ含量均表现出明显的季节变化。脑垂体的ＧＨ含量分别在３月份和８月份出现两个峰。４～７月的繁殖期和１１～１月的越冬期间,脑垂体的ＧＨ含量很低,而且波动不大。受水温和光周期的影响,大鳍血清ＧＨ水平表现为从冬季（１１～１月）到春季（２～４月）逐渐上升,夏季急剧升高,到夏末（７月底）达到最高,一直持续到秋季。大鳍血清ＧＨ含量的变化与生殖周期密切相关,最低的ＧＨ含量出现在性腺静止期,其次为性腺发育期,再次为性腺成熟期,在产卵期急剧升高,最高为性腺退化期。 相似文献
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瓦氏黄颡鱼生长激素基因克隆及其组织特异性表达分析 总被引：1，自引：1，他引：0
生长激素(growth hormone,GH)对脊椎动物的生长发育及代谢具有重要作用。采用RT-PCR和RACE技术,克隆了瓦氏黄颡鱼垂体GH cDNA全长序列,应用real-time qPCR法对不同组织中GH mRNA的表达进行检测。序列分析表明,GH cDNA(GenBank登录号:GU395549)序列全长1 203 bp,其5’端非编码区77 bp、3’端非编码区523 bp,开放阅读框(open reading frame,ORF)603 bp,由此推导GH前体蛋白由200个氨基酸组成。同源性比较结果表明,瓦氏黄颡鱼与同目鱼类的GH编码序列同源性较高,与哺乳类和鸟类的同源性较低。Real-time qPCR结果显示,GH mRNA在垂体中的表达量最高,其次是脑、肌肉、肝脏、脂肪组织、胃、脾脏、卵巢或精巢,而在肾脏、心脏、鳃和肠中没有明显的表达。实验结果表明,GH基因在瓦氏黄颡鱼组织中广泛表达,提示GH可能以旁分泌或自分泌的方式对其生长和繁殖发挥重要作用。 相似文献
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Ghrelin was recently demonstrated as an endogenous ligand of the growth hormone (GH) secretagogue receptor (GHS-R), which could promote the release of GH in mammal significantly. The present study conducted to determine whether ghrelin stimulate the release and synthesis of GH in orange-spotted grouper (Epinephelus coioides). Rat ghrelin was incubated with the pituitary fragments of grouper in static culture system. The culture medium was collected at 1, 6, 12, 18 and 24 h after incubation to detect the contents of GH by homologous radioimmunoassay. The level of GH mRNA in the pituitary fragments was measured by a sensitive chemiluminescent ribonuclease protection assay. The results showed that rat ghrelin not only stimulated the release of GH but also augmented the GH mRNA level in grouper. It suggested that the ghrelin-like peptide and the GHS-R involved in the regulation of GH synthesis and release in grouper. The present study would provide a better understanding of the regulatory mechanism of GH release in marine fish. 相似文献
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Lázaro Wender Oliveira de Jesus Chayrra Chehade Fabiano Gonçalves Costa Maria Inês Borella 《Fish physiology and biochemistry》2014,40(3):897-909
In this study, we describe for the first time the details of the pituitary gland morphogenesis and the ontogeny of adenohypophyseal cells of a South American Characiform species with great importance for Brazilian Aquaculture, Salminus brasiliensis (Characiformes, Characidae), from hatching to 25 days after hatching (dah), by histochemical and immunocytochemical methods. The pituitary placode was first detected at hatching (0 dah), and the pituitary anlage became more defined at 0.5 dah. The neurohypophysis (NH) development started at 3 dah, and the early formation of its stalk at 12.5 dah. An increase in adenohypophyseal and NH tissues was also observed, and in juveniles at 25 dah, the pituitary displayed similar morphology to that found in adults of this species, displaying the main features of the teleost pituitary. PRL cells were detected at 0.5 dah, together with ACTH and α-MSH cells, followed by GH and SL cells at 1.5 dah. β-FSH cells were detected at 25 dah, while β-LH cells at 5 dah. The pituitary development in this species comprises a dynamic process similar to other teleosts. Our findings in S. brasiliensis corroborate the heterogeneity in the ontogeny of adenohypophyseal cells in teleosts and suggest a role for adenohypophyseal hormones in the early development of this species. 相似文献