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  • 1
    Electronic Resource
    Electronic Resource
    Dynamics of excretion of 17α,20β-dihydroxy-4-pregnen-3-one 20-sulphate, and of the glucuronides of testosterone and 17β-oestradiol, by urine of reproductively mature male and female rainbow trout (Oncorhynchus myklss) (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 44 (1994), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Levels of sulphated 17α20β-dihydroxy-4-pregnen-3-one (17,20β-P; the oocyte maturation inducing steroid) in blood plasmas of sexually mature male and female rainbow trout Oncorhynchus mykiss, were very low in comparison to those of the free steroid. However, relatively large amounts were found in urine of both sexes.Catheters were inserted into the urinary bladders of unovulated and ovulated females and of ripe-running males, and the fish then placed in spawning channels. Three-hourly urine samples were collected between 09.00 and 18.00 hours and then a 15-h sample between 18.00 and 09.00 hours the next morning. Measurements were made of 17,20β-P-sulphale, testosterone glucuronide (T-G) and 17β-oestradiol glucuronide (E2-G). In females, the highest rates of excretion of E2-G, T-G and 17,20β-P-sulphate were found in unovulated, ovulating and ovulated females, respectively. The rates of excretion of 17,20β-P-sulphate, T-G and E2-G in ovulated females were unaffected by the presence of a male. id males, however, there was a sharp increase in the rate of excretion of 17,20β-P-suiphate and T-G in fish which were paired with an ovutated (nesting) female. A similar increase was found in males injected with male trout pituitary extract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1994.tb01589.x
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  • 2
    Electronic Resource
    Electronic Resource
    Urine of reproductively mature female rainbow trout, Oncorhynchus mykiss (Walbaum), contains a priming pheromone which enhances plasma levels of sex steroids and gonadotrophin II in males (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 44 (1994), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Urine of reproductively mature female rainbow trout was shown to contain a priming pheromone which raised the levels of 17a,20β-dihydroxy-4-pregnen-3-one (17,20β-P), testosterone and gonadotrophin II in the blood plasma of reproductively mature male rainbow trout. Milt volumes, however, were unaffected.Because it had been established in a previous study that the sulphated form of 17,20β-P is abundant in the urine of spawning rainbow trout, synthetic 17a,20β-dihydroxy-4-pregnen-3-one 20-sulphate was also tested for pheromonal activity. It was found to have only a smalt and inconsistent priming effect on steroid levels and did not alter the orientation or spawning activity of males.It was also shown that, in the majority of experiments, there was a significant drop, over the course of 24 h, in the levels of 17,20β-P and testosterone in the control groups of males.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1994.tb01590.x
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  • 3
    Electronic Resource
    Electronic Resource
    A review of the biology, handling and storage of salmonid spermatozoa (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 17 (1980), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Several aspects of salmonid sperm have been critically reviewed: structure, density, volume, chemical composition, metabolism, fertilisation techniques, motility, dilution, activation, storage at temperatures above and below 0deg; C and cryopreservation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1980.tb02804.x
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  • 4
    Electronic Resource
    Electronic Resource
    Seasonal variations in plasma concentrations of 11-ketotestosterone and testosterone in male rainbow trout, Salmo gairdnerii Richardson (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 17 (1980), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Measurements were made of plasma 11-ketotestosterone and testosterone in control and sex-reversed male rainbow trout, before and during their first spawning season (winter 1978/1979). Plasma concentrations of both androgens (in both groups) were 2–3 ng ml-1 in January 1978 (apart from some precocious spawners), rose slowly to 9–11 ng ml-1 in April and July and then increased rapidly to 100–150 ng ml-1 in November. From this time, testosterone levels declined but those of 11-ketotestosterone continued to rise to a peak of 260 ng ml-1 in February 1979. No significant differences in hormone levels were found between control male and masculinized female fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1980.tb02781.x
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  • 5
    Electronic Resource
    Electronic Resource
    Seasonal variations in sex steroids of female rainbow trout (Salmo gairdneri Richardson) (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 17 (1980), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 17β-oestradiol, testosterone, 11 -ketotestosterone and calcium were measured in plasma of female rainbow trout over the course of a single spawning season. The patterns of rise and fall of the levels of 17β-oestradiol and calcium during sexual maturation were similar to those demonstrated by other workers. Very high levels of testosterone were found in plasma of sexually mature fish—mean level 211 ng ml-1 in November and 115 ng ml-1 in January. Ovulation occurred from December to February.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1980.tb02790.x
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  • 6
    Electronic Resource
    Electronic Resource
    Evaluation of biochemical methods for the non-destructive identification of sex in upstream migrating salmon and sea trout (2005)
    Oxford, UK; Malden, USA : Blackwell Publishing Ltd/Inc.
    Journal of fish biology 67 (2005), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Female-specific markers of reproductive activity [plasma 17β-oestradiol (E2), vitellogenin (VTG) and alkali-labile phosphoprotein phosphorous (ALP)] were measured over 12 months in a captive population of brown trout Salmo trutta. During the early months of the reproductive season (February to May) and using the concentration of plasma E2 or plasma ALP as a marker for females the proportion of fish in which sex was misidentified was high (15–50%). The misidentification rate was considerably lower (1–8%) using plasma VTG. Preliminary evaluation of a commercial immunochromatographic VTG test system as a screen for the presence or absence of VTG in plasma from brown trout provided results that were consistent with those obtained from direct measurement of plasma VTG levels by enzyme-linked immunosorbent assay (ELISA). These preliminary conclusions were verified by sampling upstream-migrating anadromous brown trout, sea trout, and Atlantic salmon Salmo salar trapped over a 6 month period. Plasma E2 levels did not satisfactorily discriminate between male and female sea trout and Atlantic salmon. Plasma VTG levels in both species, however, were bimodally distributed and it was assumed that this divergence corresponded to male (plasma VTG levels 〈10 μg ml−1) and female (plasma VTG levels 〉800 μg ml−1) fishes. Plasma ALP provided a more accurate indication of sex in the wild Atlantic salmon and sea trout than was suggested by the pilot study on captive brown trout. The commercial immunochromatographic VTG test system provided results that were wholly consistent with the data obtained from the trapped fishes by direct measurement of plasma VTG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2005.00853.x
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  • 7
    Electronic Resource
    Electronic Resource
    Plasma steroid concentrations in relation to the reproductive cycle of cultured male Rhamdia quelen (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 61 (2002), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The plasma concentrations of testosterone (T) of cultured jundiáRhamdia quelen increased progressively during spermatogenesis and reached a peak at the beginning of spermiation (e.g. fluidization of the sperm and production of milt). Plasma peaks of T occurred simultaneously to the highest production of T by the testis, however, both plasma concentrations and testis production of T decreased progressively during spermiation. Concentrations of 11-ketotestosterone (11-KT) peaked c. 1 month after the peak of T, concomitant with enhanced production of 11-KT by the testis. The concentrations of 11-KT during the first cycle were extremely high (〉 1 μg ml−1), but less during the second and third cycles, suggesting that this steroid is most important during the pubertal phase in male jundiá. Plasma concentrations of both 17-hydroxy-4-pregene-3,20-dione (17-P) and 17,20β-dihydroxy-4-pregen-3-one (17,20β-P) were significantly higher during spermiation than at any other times, and showed little variation. The pattern of steroid changes was cyclical and consistent with their proposed roles in male fish reproduction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2002.tb00909.x
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  • 8
    Electronic Resource
    Electronic Resource
    Female rainbow trout urine contains a pheromone which causes a rapid rise in plasma 17,20β-dihydroxy-4-pregnen-3-one levels and milt amounts in males (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 50 (1997), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Previous studies have shown that spermiating male rainbow trout respond to the presence of female urine in the water with significant increases in plasma levels of gonadotrophin II, 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) and testosterone. The present results show that males only need a single brief exposure to female urine in order to respond; levels of 17,20β-P rise significantly within 1 h of exposure, and peak between 3 and 4 h. Also, milt amounts increase significantly following exposure of males to female urine. Levels of 17,20β-P are also related positively to the amount of female urine to which the males are exposed. Furthermore, when live females are placed, out of physical and visual contact, in the same tank as males, levels of 17,20β-P rise in the same way as in males which are exposed to female urine. However, if females are fitted with urinary catheters (which drain the urine outside the tank), males respond more slowly. These results indicate that urine is the main source of the male ‘priming’ pheromone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1997.tb01343.x
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  • 9
    Electronic Resource
    Electronic Resource
    A reappraisal of human β MSH (1974)
    [s.l.] : Nature Publishing Group
    Nature 252 (1974), S. 492-493 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It has been shown that the human pituitary contains peptides identical to ? lipotrophin and g lipotrophin4,5, and it is evident that 'human ? MSH', although it differs in length from the other mammalian ? MSHs, is also derived by cleavages of these molecules. The very close correspondence of the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/252492a0
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  • 10
    Electronic Resource
    Electronic Resource
    Seasonal changes in plasma gonadal steroid concentrations and gonadal morphology of male and female tench (Tinca tinca, L.) (2003)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 34 (2003), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In order to gain a better understanding of the reproductive cycles of male and female tench (Tinca tinca), gonadosomatic index, gonad histology and plasma concentrations of estradiol-17β (E2), testosterone, an drostenedione, 11-ketotestosterone (11-KT), 17,20β, 21-trihydroxy-4-pregnen-3-one (17,20β,21-P), 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) and 17,20α-dihydroxy-4-pregnen-3-one (17,20α-P) were measured at the four seasons of the year, plus a further sampling coincident with the peak of spawning in early July. As expected, in both males and females, the plasma concentrations of androgens (excluding 11-KT in females – undetectable) and C21 steroids were significantly more elevated in the spring and summer (when most gonadal development took place) than in the autumn and winter. The only unexpected finding was that 17,20β-P and 17,20β,21-P, the steroids that are normally associated with oocyte final maturation in females and spermiation in males, were found in substantial amounts in both pre-vitellogenic, pre-spermatogenic and post-spawning fish. This suggests that these steroids may have other as yet unidentified roles in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2003.00926.x
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