Swim bladder tumor in the young adult scoliotic medaka (Oryzias latipes)     

Satoshi Furukawa  Yumiko Hoshikawa  Kota Irie  Yusuke Kuroda  Kazuya Takeuchi 《Journal of toxicologic pathology》2021,34(2):157

A swim bladder tumor was detected in one scoliotic medaka aged 22 weeks. The tumor was located in the dorsal abdominal cavity, with maximum dimension of 1,850 × 1,500 µm. No swim bladder lumen was identified, and the region where the swim bladder lumen would have been located, was replaced with adipose tissues. The tumor was a non-invasive, expansile, and encapsulated solid mass with a few cysts, and comprised a homogenous population of well-differentiated, densely packed, gas glandular epithelium-like cells. The tumor mass was connected to a rete mirabile that showed a hyperplastic capillary plexus; however, the tumor cells did not invade the rete mirabile, thereby revealing that the tumor was an adenoma originating from the gas glandular epithelium of the swim bladder. Since proliferative lesions in the swim bladder have been reported in some teleosts with skeletal deformations, including medaka, the occurrence of a spontaneous swim bladder tumor in teleosts is considered to be closely associated with various types of skeletal deformation, and spinal curvature in particular.  相似文献   

Anaesthetic Effects on the Hepatic Portal Vein and on the Vascular Resistance of the Tail of the Chinook Salmon (<Emphasis Type="Italic">Oncorhynchus tshawytscha</Emphasis>)     

S.?E.?Rothwell  M.?E.?ForsterEmail author 《Fish physiology and biochemistry》2005,31(1):11-21

We used blood vessel myography and a perfused tail preparation from the Chinook salmon (Oncorhynchus tshawytscha) to investigate the effect of 2 commercially used fish anaesthetics, AQUI-S^TM and MS222, on vascular tone. Hepatic portal vein rings were exposed to 1 × 10⁻⁷ M adrenaline in the presence or absence of either AQUI-S^TM or MS222 and changes in vessel tension measured. Tail preparations were perfused with saline containing increasing concentrations of either anaesthetic. Exposure to either anaesthetic did not alter the response of vessel rings to adrenaline in vitro. However, both anaesthetics caused a significant (P ≤ 0.05) decrease in vessel tension when compared to controls. In tail preparations, perfusion with either anaesthetic caused a significant (P ≤ 0.05) yet reversible, dose dependent decrease in vascular resistance. Further to this, it was found that for both anaesthetics there was a significant effect of fish holding time on the response of preparations, with fish that were acclimated for less than 1 week exhibiting less vasodilation in response to anaesthetic exposure. We conclude that commonly used concentrations of AQUI-S^TM and MS222 can have a direct effect on vascular tone of salmon vessels, causing a significant but reversible vasodilation of vessels. This vasodilation may offset increases in haematocrit seen during anaesthesia in the whole animal, and in recovery prevent large rises in peripheral resistance associated with catecholamine release. A reduced vascular resistance may allow the heart to pump greater volumes of blood during recovery.  相似文献   

Mismatch between patterns of circulating and testicular androgens in African catfish, Clarias gariepinus     

J.E.B. Cavaco  H.F. Vischer  J.G.D. Lambert  H.J.Th. Goos  R.W. Schulz 《Fish physiology and biochemistry》1997,17(1-6):155-162

11-Ketotestosterone (11-KT) is an important plasma androgen in male African catfish. The quantitatively predominating androgen produced by the testis, however, is 11-hydroxyandrostenedione (OHA). Our working hypothesis to explain this mismatch assumed that OHA is converted to 11-KT at extratesticular sites. First, we examined the in vivo metabolism of [³H]-OHA in mature males after sham-operation or removal of either the testes (TC), the seminal vesicles (SVC), or both (TSVC) by analysing the pattern of circulating [³H]-androgens two hours after intravenous injection of [³H]-OHA. [³H]-OHA was converted to [³H]-11-KT to the same extent in all groups, indicating that neither ablation of testes nor of seminal vesicles, or both attenuates this conversion. We then examined the in vitro metabolism of [³H]-OHA by several types of tissues. Liver and seminal vesicle tissue were found to produce significant amounts of [³H]-11-KT. The conversion capacity in vivo was assessed by injecting TSVC-castrated males with increasing doses of radioinert OHA, followed by the quantification of OHA and 11-KT plasma levels. Saturation of the conversion capacity was not reached but the 11-KT production capacity is at least 80 ng per ml of plasma per hour. Moreover, liver fragments were tested for their OHA to 11-KT conversion capacity in vitro using increasing concentrations of radioinert OHA. The 11-KT producing increased with time and OHA concentration. The production rate was 90 pg 11-KT mg^-1 liver h^-1. Considering the results of the surgical experiments and the fact that the total hepatic mass by far exceeds that of the seminal vesicles, we conclude that the hepatic conversion is of primary relevance in vivo.  相似文献   

Hormonal regulation of renal inorganic phosphate transport in the winter flounder, Pleuronectes americanus     

J.L. Renfro 《Fish physiology and biochemistry》1997,17(1-6):377-383

Intestinal uptake and renal excretion are the primary determinants of inorganic phosphate (P_i) balance in teleosts. In general, teleost kidneys may either reabsorb filtered P_i or secrete excess P_i into the urine. Primary monolayer cultures of flounder (Pleuronectes americanus) renal proximal tubule epithelium (PTCs) have helped identify several hormones that may participate in conservation or excretion of P_i. Mounted in Ussing chambers, the monolayer cultures can be used to assay transepithelial P_i transport. Several factors, including metabolic acidosis, elevation of plasma [P_i], salmon stanniocalcin, salmon somatolactin and mammalian prolactin, have now been shown to alter transepithelial P_i transport in winter flounder PTCs. Salmon stanniocalcin (STC) stimulated P_i luminal-to-peritubular transport (reabsorption) at a dosage of 12.5–50 ng/ml (0.25–1.0 nM). Net P_i transport changed within 30 min and progressively increased from slight net secretion in untreated controls to net reabsorption after 3 h. The target and function of somatolactin have been uncertain. In our hands salmon somatolactin (sSL) also stimulated P_i reabsorption by flounder PTCs in a dose-dependent manner at physiological levels of the hormone (12.5 ng/ml). Net P_i transport was significantly altered by sSL within 2 h after the initial exposure. Neither sSL nor STC had any effect on transepithelial Ca²⁺ transport. The effects of both sSL and STC were mimicked by forskolin, whereas H-89, a highly specific protein kinase A inhibitor, significantly decreased the effects of the hormones as well as forskolin-induced P_i reabsorption. Furthermore, the production and release of cAMP were increased more than two-fold following exposure to STC or sSL. The data indicate that STC and sSL directly stimulate net renal P_i reabsorption by a cAMP-dependent pathway. In addition, mammalian prolactin greatly, and salmon growth hormone slightly, increased net P_i reabsorptive flux, whereas salmon prolactin had no effect. These results appear to be related to the location of the cysteine disulfide bonds within the molecular structure. Although somatolactin and stanniocalcin may both stimulate renal P_i conservation, their actions may be related to different physiological conditions.  相似文献   

Steroidogenic capacity of coho salmon ovarian follicles throughout the periovulatory period     

Dr Glen Van Der Kraak  Edward M. Donaldson 《Fish physiology and biochemistry》1986,1(4):179-186

Coho salmon follicles obtained at various times throughout the periovulatory period were incubatedin vitro with graded amounts of partially purified salmon gonadotropin (SG-G100) for 24 h and the amounts of 17β-estradiol, testosterone and 17α20β dihydroxy-4-pregnen-3-one (17α20βP) released into the media determined by radioimmunoassay. By this approach, the pattern of steroid secretion by ovarian follicles was shown to change in relation to the developmental status of the oocyte. Full-grown immature follicles produced large amounts of 17β-estradiol but negligible amounts of testosterone and 17α20βP. Both basal and gonadotropin-stimulated 17β-estradiol production was subsequently reduced with advancing oocyte development. In contrast, the production of testosterone and 17α20βP increased during the course of ovarian development with testosterone production highest in follicles with a peripheral germinal vesicle and 17α20βP production highest in matured and postovulatory follicles. These data are discussed in relation to information on the preovulatory changes in circulating levels of steriod hormones in salmonids.  相似文献   

Absence of binding and impermeability to ferritins of gill endothelium in marine teleosts     

R. B. Boyd  J. Atkin  V. W. Thompson  A. L. DeVries 《Fish physiology and biochemistry》1990,8(1):53-60

The surface binding characteristics and permeability properties of the endothelium of secondary lamellae from the gills of several species of marine teleosts were investigated by introducing cationized ferritin and native ferritin into the microcirculation under normal environmental conditions. Neither type of ferritin bound to the luminal surface of the gill endothelium. No transcellular movement of cationized ferritin was detected, either via transendothelial channels or individual vesicles, nor was passage of cationized ferritin through the tight intercellular junctions of the endothelium observed. Anionic binding sites in the endothelial basement membranes could not be identified. Binding and transport of ferritin were unaffected by normal changes in environmental temperatures over the range of -2 to + 15°C. These findings suggest that the endothelial cell surface of the gills from these fishes is a primary barrier to the extracapillary movement of blood borne constituents.  相似文献   

Drinking behaviour in sea water and fresh water teleosts,the role of the renin-angiotensin system     

M. N. Perrott  C. E. Grierson  N. Hazon  R. J. Balment 《Fish physiology and biochemistry》1992,10(2):161-168

Basal drinking rate and responses to administered angiotensin were examined in 12 species of fish. The responses of representative euryhaline, stenohaline marine and fresh water species to pharmacological manipulation of endogenous renin-angiotensin system (RAS) activity were also investigated.Basal drinking rates were consistently low in stenohaline and euryhaline fresh water fish, and all species examined showed an increased imbibition in response to administered angiotensin. Marine fish drank large volumes of water, rates varying considerably between species, with euryhaline species exhibiting lower rates than stenohaline groups. The extremely high drinking rates observed in the sea scorpion were associated with a high plasma osmolality. With the exception of the sea scorpion, all other species examined in sea water showed a further rise in drinking in response to exogenous angiotensin.Although the freshwater stenohaline carp showed a dipsogenic response to angiotensin, it was apparently unable to evoke this response when fish were acclimated to brackish water. The high drinking rates of both euryhaline and stenohaline fish held in sea water appeared dependent upon an activated endogenous RAS, and were lowered following inhibition of Al to All conversion by Captopril. Drinking was further stimulated in these marine species following stimulation of endogenous RAS activity by the administration of the hypotensive agent Papaverine. The study endorses a role for the RAS in the control of adaptive drinking in euryhaline and stenohaline marine teleosts.  相似文献   

Production, release and olfactory detection of sex steroids by the tench (Tinca tinca L.)     

M.L. Pinillos  A.I. Guijarro  M.J. Delgado  P.C. Hubbard  A.V.M. Canário  A.P. Scott 《Fish physiology and biochemistry》2002,26(2):197-210

The present study is concerned with pheromone communication in tench (Tinca tinca L.), establishing firstly whether males have a high olfactory sensitivity to some typical teleost sex steroids and prostaglandins; and secondly whether males and females might be able to synthesise and release some of these steroids into the water. The C₂₁ steroid, 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) was found to give large electro-olfactogram responses with an estimated threshold of detection of 10⁻¹² M. The male tench were equally sensitive to glucuronidated 17,20β-P (10^−11.6 M) but 100 times less sensitive to sulphated 17,20β-P (11^−9.7 M). Preliminary data from cross-adaptation studies suggest that both the free and conjugated forms are detected by the same olfactory receptor(s). Male tench also had high olfactory sensitivity to prostaglandin F_2α (PGF_2α) and 15-keto PGF_2α (11^−11.5 and 10^−11.4 M). They were relatively insensitive, however, to testosterone (T), androstenedione (AD), 11-ketotestosterone (11-KT), 17β-oestradiol (E₂), 17,20β,21-trihydroxy-4-pregnen-3-one (17,20β,21-P) and 17,20α-dihydroxy-4-pregnen-3-one (17,20α-P). Radioimmunoassays were used to measure the steroids in plasma and water and all samples were processed for the measurement of free, sulphated and glucuronidated fractions. In females, free 17,20β-P, 17,20α-P, free and glucuronidated T, and AD in plasma showed the largest increases in response to injection with mammalian gonadotropin-releasing hormone analogue (GnRHa) or Ovaprim (a mixture of GnRHa and a dopamine inhibitor). Free 17,20β-P was released into the water at the greatest rate. Plasma concentrations of the two conjugated forms of 17,20β-P were also elevated 18 h after the administration of GnRHa, but not by as much as the free steroid. In males, AD and 11-KT showed the greatest increase in response to GnRHa and were moreover released into the water at a higher rate in the treated group than in the control. The data support a possible pheromonal role for free and glucuronidated 17,20β-P. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Thyroid hormones in eggs of various freshwater,marine and diadromous teleosts and their changes during egg development   总被引：1，自引：0，他引：1  

Masatomo Tagawa  Masaru Tanaka  Shigeki Matsumoto  Tetsuya Hirano 《Fish physiology and biochemistry》1990,8(6):515-520

Thyroid hormone concentrations in unfertilized eggs of 26 species of various freshwater, marine and diadromous teleosts were examined, together with changes in their concentrations during egg development in some species. Significant quantities of both thyroxine (T₄) and triiodothyronine (T₃) were found in eggs of all species examined. Mean T₄ and T₃ concentrations in eggs varied from 0.04 (marbled sole) to 15.00 ng/g (chum salmon), and from 0.07 (goldfish) to 9.95 ng/g (Pacific herring), respectively. T₄ concentrations were significantly greater than T₃ concentrations in eggs of most freshwater fishes, whereas T₃ concentrations were greater in seawater fishes. During the course of development, thyroid hormones in eggs decreased markedly before hatching. These findings suggest that thyroid hormones are consistently present in teleost eggs, and thus may play an important role in the egg development.  相似文献   

Estrogen receptors in the brain-pituitary complex and the neuroendocrine regulation of gonadotropin release in rainbow trout     

O. Kah  I. Anglade  B. Linard  F. Pakdel  G. Salbert  T. Bailhache  B. Ducouret  C. Saligaut  P. Le Goff  Y. Valotaire  P. Jégo 《Fish physiology and biochemistry》1997,17(1-6):53-62

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