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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 60 (2002), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Electrophysiological studies demonstrated that the olfactory epithelium of mature male brown trout Salmo trutta parr was acutely sensitive to F-series prostaglandins (PGFs) PGF1α and PGF2α, with detection threshold concentrations of 10−11 M. The olfactory epithelium was also sensitive to the PGF metabolite 15-ketoPGF2α (threshold 10−8 m), but did not detect a further metabolite, 13,14,-dihydro-15-ketoPGF2α Immature brown trout did not detect any of the prostaglandins tested. Exposure of mature male brown trout parr to waterborne PGF1α and PGF2α (concentration 10−8 m), resulted in significant increases in levels of expressible milt and the plasma concentrations of 17,20β-dihydroxy-4-pregnen-3-one, testosterone and 11-ketotestosterone. The olfactory epithelium of both immature and mature male brown trout parr was sensitive to the urine and ovarian fluid from ovulated female brown trout. Exposure of mature male brown trout parr to ovarian fluid resulted in an increase in the levels of plasma 17,20β-dihydroxy-4-pregnen-3-one whilst exposure to urine increased the levels of expressible milt. In addition, PGF2α was found to be present within both the urine and ovarian fluid of mature female brown trout. It is suggested that the F-series prostaglandins have a role as priming pheromones in male brown trout.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 56 (2000), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The feeding rate of a group (DS) of two small, two medium and two large 1+ Arctic charr Salvelinus alpinus was higher than in a group of six fish of the same size (SS), suggesting that size distribution had an effect on feeding behaviour, with a correlation between the size of the fish and the amount of food eaten–the largest fish eating the most. Against predictions, rate of aggression was not higher in the SS groups; rather there was a modest tendency of higher aggression among individuals in the DS groups.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 67 (2005), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The present study investigated, for the first time, a non-invasive technique for monitoring cortisol levels in fishes that had been implanted with electronic transmitters. This technique involved the measurement of cortisol released into the water by individual fish. Carp Cyprinus carpio and roach Rutilus rutilus that had been tagged with miniature dummy acoustic transmitters responded to the surgical implantation of the tags with an immediate (1 to 4 h) increase in cortisol concentrations in the water. These amounts of cortisol were higher than in ‘handled only’ and ‘handled and anaesthetized’ groups. Estimated cortisol release rates for both species correlated well with the direct measurements in the water. In both species, water cortisol concentration and cortisol release rates returned to pre-stress levels within 12 h of tag-insertion, and remained low for the remainder of the experiment. The calculation of cortisol release rates highlighted a difference of a factor of about four between peak release rates in carp and roach. There was no evident long-term cortisol stress response to the presence of a tag in the body cavity in either species.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden , USA : Blackwell Publishing Ltd/Inc
    Journal of fish biology 64 (2004), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Electro-olfactogram (EOG) recordings of the olfactory epithelium of both male and female roach Rutilus rutilus demonstrated that both sexes were able to detect free and glucuronidated 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) with high sensitivity. Male, but not female, roach were also sensitive to androstenedione. Sexually mature female roach were shown to release free 17,20β-P, glucuronidated 17,20β-P and androstenedione into the water; for all three steroids, the rate of release was significantly enhanced by injection of carp pituitary extract (CPE). A series of trials was also carried out which showed that mature males, and to a lesser extent immature males and females, were able also to release free and glucuronidated 17,20β-P, both before and after CPE treatment. Water extracts from containers that had held CPE-treated mature male and female roach were examined for the presence of other steroids. This revealed that free and glucuronidated 17,20β-P plus free and glucuronidated 17,20β,21-trihydroxy-4-pregnen-3-one (17,20β, 21-P) predominated in water extracts from both sexes. The free moieties of 17,20α-dihydroxy-4-pregnen-3-one, 17-hydroxyprogesterone and 11-deoxycortisol were found at concentrations which were between four and 20 times lower than those of free 17,20β-P. Androstenedione was found at concentrations which were 25-fold lower than those of 17,20β-P. Despite its apparent high rate of release by sexually mature male and female roach, free 17,20β,21-P was found not to exhibit any EOG activity at the highest dose tested (10−7 M).
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 264-268 (May 2004), p. 1859-1862 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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