Ovarian follicle growth, maturation, and ovulation in teleost fish   总被引：12，自引：0，他引：12  

Reynaldo Patiño  Craig V. Sullivan 《Fish physiology and biochemistry》2002,26(1):57-70

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Effect of diet and ration on the relationship between plasma GH and IGF-1 concentrations in Arctic charr, Salvelinus alpinus (L.)   总被引：1，自引：0，他引：1  

Colin Cameron  Richard Moccia  Paula A Azevedo  & John F Leatherland 《Aquaculture Research》2007,38(8):877-886

The purpose of the study was to investigate whether dietary ration or diet composition influence the relationship between plasma growth hormone (GH) and insulin‐like growth factor‐1 (IGF‐1) in Arctic charr (Salvelinus alpinus L.). The pattern of changes in plasma GH and IGF‐1 concentrations was examined in fish fed at different ration levels (0%, 0.35% and 0.70% BW day⁻¹) for 5 weeks, and in fish fed diets containing different lipid:crude protein (LCP) ratios. Ration level significantly affected plasma GH and IGF‐1 concentrations; at 5 weeks the levels of both hormones in the food‐deprived group were significantly lower than in fish fed the 0.70% BW day⁻¹ ration. Also, plasma IGF‐1 levels in fish of each ration treatment group were significantly correlated with individual final body weight; no such correlation was found for GH. To examine the effects of dietary LCP ratios, fish were fed for up to 18 weeks, with one of four formulated diets that had LCP ratios (dry matter basis) of 0.35 (Diet 1), 0.43 (Diet 2), 0.51 (Diet 3) or 0.59 (Diet 4), or a commercial diet (Diet 5) which had an LCP ratio of 0.38. Statistical differences in plasma GH and IGF‐1 concentrations were found only after 18 weeks. Growth hormone was significantly lower in fish fed Diets 1 and 2 compared with Diets 3 and 5, and IGF‐1 was significantly lower in fish fed Diet 1 compared with Diets 2 and 5. Significant correlations between plasma GH and IGF‐1 concentrations were found only for fish fed Diets 1 and 5, suggesting that the influence of diet composition on the relationship between GH and IGF‐1 varies with the dietary LCP ratio in this species. The decline in plasma IGF‐1 concentrations during food deprivation is similar to that described in other species; however, the unexpected decrease in plasma GH during food deprivation in this study may represent a species‐specific response.  相似文献   

The reproductive brain in fish   总被引：5，自引：0，他引：5  

Olivier Kah  Isabelle Anglade  Emmanuel Leprêtre  Pierrette Dubourg  David de Monbrison 《Fish physiology and biochemistry》1993,11(1-6):85-98

In fish as in other vertebrates, the brain is actively involved in the control of reproduction, first by participating, under the influence of external factors, in the establishment of an appropriate endocrine status, but also by allowing synchronization of the partners by the time of spawning. It is now well established that the pituitary gonadotropic function is controlled by multiple stimulatory and inhibitory factors, originating mainly from the preoptic region and the mediobasal hypothalamus, both target regions for sexual steroids. Little is known about the mechanisms involved in the mediation of external and internal factors, however there is indication that internal factors, such as androgens and melatonin, known to trigger particular behavioural and endocrine responses, act both at the level of neuroendocrine territories, but also on sensorial systems, which are the actual sites of action for external factors. This paper represents an attempt to summarize and integrate the recent literature devoted to the different aspects of the brain as a major participant in the complex endocrine and behavioural mechanisms of reproduction in fish.  相似文献   

Signals controlling renin release in aglomerular toadfish     

Hiroko Nishimura  Margaret A. Madey 《Fish physiology and biochemistry》1989,7(1-6):323-329

The toadfish,Opsanus tau, lacks renal glomeruli and macula densa, but has high renal renin activity and abundant granulated cells in renal arteries and arterioles. Reduction of blood pressure (BP) or blood volume by hemorrhage or vasodilatory drugs causes renin release, indicating that an intrarenal or extrarenal pressure- or volume-sensitive mechanism exists for controlling renin release in the toadfish. Thus, we examined whether 1) β-adrenergic receptor-mediated activation of renin release, and 2) calcium influx which may underlie the baroreceptor mechanism are involved in the cellular control of renin release. Acute injection of isoproterenol (1 μg/kg, n = 6) decreased BP and increased plasma renin activity (PRA) 4–5 fold in unanesthetized toadfish. Propranolol abolished both effects, but did not decrease basal PRA levels.In vitro superfusion of renal slices with bicarbonate Ringer's solution showed a steady secretion of renin, and addition of 50 mM K⁺ (K⁺ methylsulfate replacing NaCl, n = 10) to the superfusate markedly suppressed renin secretion. Nifedipine (10⁻⁵ M, n = 8) completely restored the high K⁺-induced inhibition of renin secretion from renal slices, whereas isoproterenol (10⁻⁴ M, n = 6) neither increased basal renin secretion nor restored K⁺-induced renin suppression. These results suggest that calcium influx may mediate inhibitory messages for renin secretion, while the β-adrenoceptor-mediated activation of granulated cells appears absent in toadfish.  相似文献   

Cloning and sequence analysis of hypothalamus cDNA encoding tilapia melanin-concentrating hormone     

Diet Gröneveld  Mark J. Hut  Paul H. M Balm  Gerard J. M. Martens  Sjoerd E. Wendelaar Bonga 《Fish physiology and biochemistry》1993,11(1-6):117-124

Melanin-concentrating hormone (MCH) is a neuroendocrine peptide involved in the regulation of skin pigmentation in teleosts. We isolated and sequenced a 543 bp hypothalamic cDNA encoding the MCH-preprohormone of tilapia (Oreochromis mossambicus). Initially, polymerase chain reaction (PCR) experiments were performed on hypothalamic RNA with a synthetic oligonucleotide primer corresponding to a conserved region of salmon and mammalian MCH peptide and an oligo dT primer. A 0.2 kb PCR fragment was obtained and found to have low but significant nucleotide sequence similarity with the 3′ ends of known MCH-mRNAs. Subsequently, the PCR fragment was used to screen λZAP cDNA libraries constructed from tilapia hypothalamic poly(A⁺) RNA. The cloned tilapia MCH preprohormone cDNA encodes a 133-amino acid protein of which 17 amino acids belong to the signal peptide. The MCH peptide sequence is located at the carboxy terminus of the preprohormone structure and is preceded by a pair of arginine residues which can serve as a proteolytic cleavage site. 23 to 25 amino acids further upstream in the prohormone structure three consecutive basic residues are present. Cleavage at this site would yield a 22-amino acid MCH gene-related peptide (Mgrp), which is much larger than (12− to 13-amino acid) salmon and mammalian Mgrp. A comparative structural analysis between tilapia preproMCH and its salmon and mammalian counterparts revealed that the MCH peptide sequence is very well conserved (100% identity with salmon and 75% identity with both rat and human MCH). In contrast, the remaining parts of the preproMCH structures have diverged considerably. Northern blot analysis revealed the presence of tilapia preproMCH mRNA in the hypothalamus and not in other brain regions nor in several peripheral tissues.

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Résumé La MCH (melanin-concentrating hormone) est un peptide neuroendocrinien impliqué dans la régulation de la pigmentation de la peau chez les Téléostéen. Nous avons isolé et séquencé un ADNC hypothalamique de 543 pairs de bases codant pour la préprohormone de la MCH de tilapia (Oreochromis mossambicus). Ce travail a débuté par des expériences de PCR (Polymerase Chain Reaction) qui ont été réalisées sur des ARNm hypothalamiques avec comme amorces un oligonucléotide synthétique correspondant à une région conservée du peptide MCH de saumon et de mammifère et un oligo dT. Un fragment de 0.2 kb a ainsi été obtenu par PCR et l'analyse de sa séquence nucléotidique montre une similitude faible mais significative avec les extrémités 3′ des ARNms de MCH connus. Ensuite ce fragment a été utilisé pour cribler des banques de cDNA construites dans λZAP à partir d'ARN poly (A⁺) d'hypothalamus de tilapia. L'ADNc de la préprohormone de MCH de tilapia code pour une proteine de 133 acides aminés dont 17 constituent le peptide signal. Le peptide de la MCH est localisé dans l'extrémité carboxy de la préprohormone et se trouve précédé par une pair de résidus arginine qui servent de site de coupure protéolitique. De plus, 3 résidus basiques consécutifs sont présents à 23–25 acides aminés en amont de la structure de la prohormone. La coupure à ce site permettrait d'obtenir un peptide associé au gène de la MCH (Mgrp) de 22 acides aminés, ce qui est beaucoup plus grand (de 12 à 13 acides aminés) que les Mgrp de saumon ou de mammifères. Une analyse structurale comparée entre la preproMCH de tilapia et la preproMCH de saumon et de mammifères montre que la séquence du peptide MCH est très conservée (100% d'identité avec le saumon et 75% d'identité avec la MCH humaine ou de rat). Par contre, les autres parties de la structure de la preproMCH ont divergé considérablement. L'analyse par “Northern Blot” met en évidence la présence d'ARNm de preproMCH dans l'hypothalamus de tilapia mais pas dans les autres régions du cerveau ni dans plusieurs tissus périphériques.

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Cardiovascular,respiratory, and blood adjustments to hypoxia in the Japanese eel,Anguilla japonica     

D. K. O. Chan 《Fish physiology and biochemistry》1986,2(1-4):179-193

The cardioventilatory performance of the Japanese eel,Anguilla japonica, was evaluated during acute exposure to hypoxia. The eel became an oxygen conformer as ambient PO₂ fell below the critical value of 110 mmHg. Although arterial and venous PO₂ also fell progressively, the arterial O₂ content remained constant down to an ambient PO₂ of about 60 mmHg. Arterial blood O₂ saturation was maintained at 85% even at 40 mmHg. The increase in the supply of O₂ to the animal during hypoxia was due to a combination of adaptive adjustments: (1) an increase in ventilation: perfusion ratio brought about mainly be bradycardia; (2) an increase in respiratory exchange surface area which was manifested as an increase in branchial blood transit time and quantified as a rise in transfer factor, water-blood overlap coefficient and utilization (%); (3) an increase in blood O₂ affinity and capacitance coefficient as a result of respiratory alkalosis and Bohr-Root shift and a decrease in haemoglobin allosteric modulator (GTP, ATP) concentrations in the RBC. These factors together helped to increase the efficiency of O₂ transfer across the gills.  相似文献   

The glutathione S-transferases of fish   总被引：1，自引：0，他引：1  

I. A. Nimmo 《Fish physiology and biochemistry》1987,3(4):163-172

Substantial soluble glutathione S-transferase activity and millimolar reduced glutathione (GSH) are present in most tissues of both teleosts and elasmobranchs. The hepatic enzymes of fish conjugate a range of electrophilic substrates with GSH, although their specificities are less broad than those of the transferases in rodent liver. There is no good evidence that fish transferases have ligandin-like activity or a suicide function. All fish livers tested have several transferase isoenzymes. They are dimers of subunits whose M_rs are about 25 kDa and which may have different catalytic properties. In some species transferase activity is induced by agents such as phenols or 3-methylcholanthrene. Glutathione S-transferases are important detoxication enzymes in fish.  相似文献   

Histological observation of the reproductive system in a viviparous teleost Xenotoca eiseni Rutter 1896 (Cyprinodontiformes: Goodeidae)     

Atsuo Iida  Jumpei Nomura  Eiichi Hondo 《Anatomia, histologia, embryologia》2021,50(1):161-168

Xenotoca eiseni is a viviparous teleost belonging to the family Goodeidae. Here, we report histological observations of the reproductive organs in an adult male, an adult female, a pregnant female with intraovarian embryo and an extracted embryo of X. eiseni. High-resolution images of haematoxylin–eosin-stained sagittal sections revealed the detailed structure of gonads, gametes and reproductive components of the mother–embryo relationship. In the male, mature spermatozoa in the epididymis formed sperm packages. In the female, oogenesis proceeded asynchronously in the ovarian wall, and various stages of oocytes were observed in single ovary. In both sexes, genital openings were located between the anus and anal fin. Developing embryos were observed in an ovary of the pregnant female. Fine structures of components of the mother-to-embryo nutrient supply, ovarian septum and trophotaenia were observed in the pregnant ovary. An immature gonad prior to gamete formation was identified in the extracted embryo. With the aim of supporting the development and extension of studies on this viviparous teleost, we have shared our histological images as raw data in an open online archive, the 'NAGOYA repository ( http://hdl.handle.net/2237/00032456 )'. Our goal is a comprehensive understanding of the viviparous system in fish using both histological observation and molecular biology methods including genomics and proteomics.  相似文献   

Blood cleansing cells in head kidney and spleen in Buenos Aires tetra, Hyphessobrycon anisitsi (Eigenmann), (Characidae: Teleostei)     

Leknes IL 《Journal of fish diseases》2012,35(6):455-460

The general structure and cell types in kidney and spleen in Buenos Aires tetra, Hyphessobrycon anisitsi, family Characidae, are described. The capability and capacity of these organs to clean foreign ferritin from the blood stream are analysed and compared. Head kidney was mainly composed of neutrophils, macrophages, lymphocytes and other white blood cells, whereas unmatured and matured red blood cells were few in number. Spleen often contained much red pulp, that is mainly matured red blood cells between splenic cords, often with some macrophages and neutrophils in the latter. Occasionally, this pulp contained large volumes of unmatured red blood cells, particularly in the periphery of the spleen. The splenic white pulp consisted of ellipsoids composed of an inner endothelial layer covered by a thick sheet of white blood cells, which in the periphery consisted mainly of macrophages. Erythrocytes occupied nearly the entire splenic volume in some specimens, whereas up to half of this volume was filled by ellipsoid macrophages, neutrophils, lymphocytes and other white blood cells in other specimens. The macrophages and sinusoidal endothelial cells in kidney and spleen from ferritin-injected specimens were tightly packed by yellow-brown granules or Prussian blue precipitations, in tissue treated with Mallory stain or acid ferrocyanide, respectively, suggesting a large uptake of foreign ferritin. In the present tetra large amounts of white blood cells are developed in head kidney, where macrophages and sinusoidal endothelial cells play important roles in the cleansing of scavenger and foreign molecules and particles from the blood stream. The spleen seems primarily to be a site for iron recycling and production and storage of red blood cells. Sometimes, however, it was rich in macrophages, neutrophils, lymphocytes and other white blood cells, suggesting functions like blood cleansing and non-specific and specific defence in such specimens.  相似文献   

硬骨鱼类渗透压的内分泌激素调节机制   总被引：2，自引：0，他引：2  

马慧  柳淑芳  马骞  王秀利  庄志猛 《水产科学》2012,31(1):55-59

正在400多科20 000多种海淡水硬骨鱼类中,有些鱼类只能生活在淡水或海水中,有些鱼类则能自由出入海淡水。这些鱼类能够在盐度变化很大的环境中生存主要依靠鳃等渗透调节器官对盐分的调节。鱼类的鳃上皮组织绝大部分为扁平细胞,但具有离子调节功能的细胞却是那些为数不多  相似文献