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  • 1.
    Hallgren, Stefan
    et al.
    Södertörn University, School of Life Sciences.
    Linderoth, Maria
    Olsén, K Håkan
    Södertörn University, School of Life Sciences.
    Inhibition of cytochrome p450 brain aromatase reduces two male specific sexual behaviours in the male Endler guppy (Poecilia reticulata)2006In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 147, no 3, p. 323-328Article in journal (Refereed)
    Abstract [en]

    In mammalian and avian vertebrate groups, androgens act as controlling agents on male aggression and courtship behaviour by their conversion to oestrogens by cytochrome P450 aromatase in well-defined brain regions. Despite the fact that bony fishes have exceptionally high brain aromatase activity, little is known about it's possible regulatory effects on the reproductive behaviours of teleosts. In this study, Endler guppy males (Poecilia reticulata) were subjected to 26-29 days of 24-h exposure to two different concentrations (15 and 100 pg/L) of the aromatase inhibitor fadrozole in the water. Compared with the control males, two of three courtship activities in males exposed to the higher concentration were reduced when they were paired with receptive stimulus females. Reduction in brain aromatase activity was confirmed in both exposed groups with the use of the tritiated water assay.

  • 2.
    Olsén, K Håkan
    et al.
    Södertörn University, School of Life Sciences.
    Sawisky, G. R.
    Stacey, N. E.
    Endocrine and milt responses of male crucian carp (Carassius carassius L.) to periovulatory females under field conditions2006In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 149, no 3, p. 294-302Article in journal (Refereed)
    Abstract [en]

    Laboratory studies in domesticated goldfish (Carassius auratus) show that, during the preovulatory luteinizing hormone (LH) surge, females release a complex steroidal pheromone that induces in males a rapid increase of plasma LH, which in turn increases strippable milt (sperm and seminal fluid) prior to ovulation and spawning. The objective of this study was to determine if the same phenomenon occurs in a wild congener, the crucian carp (Carassius carassius), under field conditions where fish are held in natural waters under ambient temperature and photoperiod. During the spawning season in June 2003, crucian carp were trapped in a small pond near Uppsala, Sweden, and held separately by sex in floating net pens. Addition of untreated females to male pens did not change male LH concentrations or milt volume during the 17 h sampling period. In contrast.. addition of females injected with Ovaprim (TM) (to induce an LH surge and ovulation) increased male LH concentrations at all sample times (5, 9, 13, and 17 h) following female addition and increased milt volumes at all but the first (5 h) sample time. Similar increases in male LH and milt that also occurred when untreated females ovulated spontaneously after addition to male pens suggest it is female ovulatory condition, rather than injection of ovaprim per se, that induced male LH and milt responses. Males also increased LH and milt 9 It after addition of females injected with the goldfish pheromonal steroid 4-pregnen-17,20 beta-diol-3-one (17,20 beta P), suggesting that similar responses to ovaprim-injected females were due, at least in part, to release of preovulatory pheromonal steroid(s). The clear and consistent effects of ovulatory females on male LH and milt, and the fact that crucian carp adapted well to confinement.. ovulated spontaneously, and exhibited apparently normal spawning behavior, all suggest that this species can serve as a useful cyprinid model to study reproductive processes in natural conditions.

  • 3.
    Porseryd, Tove
    et al.
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Environmental Science.
    Reyhanian Caspillo, Nasim
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology. Örebro universitet.
    Volkova, Kristina
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology. Örebro universitet.
    Elabbas, Lubna
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology.
    Källman, Thomas
    Uppsala university.
    Dinnétz, Patrik
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Environmental Science.
    Olsson, Per-Erik
    Örebro universitet.
    Porsch Hällström, Inger
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology.
    Testis transcriptome alterations in zebrafish (Danio rerio) with reduced fertility due to developmental exposure to 17α-ethinyl estradiol2018In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 262, p. 44-58Article in journal (Refereed)
    Abstract [en]

    17α-Ethinylestradiol (EE2) is a ubiquitous aquatic contaminant shown to decrease fish fertility at low concentrations, especially in fish exposed during development. The mechanisms of the decreased fertility are not fully understood. In this study, we perform transcriptome analysis by RNA sequencing of testes from zebrafish with previously reported lowered fertility due to exposure to low concentrations of EE2during development. Fish were exposed to 1.2 and 1.6 ng/L (measured concentration; nominal concentrations 3 and 10 ng/L) of EE2 from fertilization to 80 days of age, followed by 82 days of remediation in clean water. RNA sequencing analysis revealed 249 and 16 genes to be differentially expressed after exposure to 1.2 and 1.6 ng/L, respectively; a larger inter-sample variation was noted in the latter. Expression of 11 genes were altered by both exposures and in the same direction. The coding sequences most affected could be categorized to the putative functions cell signalling, proteolysis, protein metabolic transport and lipid metabolic process. Several homeobox transcription factors involved in development and differentiation showed increased expression in response to EE2 and differential expression of genes related to cell death, differentiation and proliferation was observed. In addition, several genes related to steroid synthesis, testis development and function were differentially expressed. A number of genes associated with spermatogenesis in zebrafish and/or mouse were also found to be differentially expressed. Further, differences in non-coding sequences were observed, among them several differentially expressed miRNA that might contribute to testis gene regulation at post-transcriptional level. This study has generated insights of changes in gene expression that accompany fertility alterations in zebrafish males that persist after developmental exposure to environmental relevant concentrations of EE2 that persist followed by clean water to adulthood. Hopefully, this will generate hypotheses to test in search for mechanistic explanations.

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  • 4.
    Volkova, Kristina
    et al.
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology. Örebro University.
    Reyhanian Caspillo, Nasim
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology. Örebro university.
    Porseryd, Tove
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Environmental Science.
    Hallgren, Stefan
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies. Uppsala university.
    Dinnetz, Patrik
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Environmental Science.
    Olsén, Håkan
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology.
    Porsch Hällström, Inger
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies, Biology.
    Transgenerational effects of 17α-Ethinyl Estradiol on anxiety behavior in the guppy, Poecilia reticulata2015In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 223, p. 66-72Article in journal (Refereed)
  • 5.
    Volkova, Kristina
    et al.
    Södertörn University, School of Life Sciences, Environmental science.
    Reyhanian, Nasim
    Södertörn University, School of Life Sciences, Environmental science. Södertörn University, School of Life Sciences, Molecular biology.
    Kot-Wasik, Agata
    Gdańsk University of Technology.
    Olsén, Håkan
    Södertörn University, School of Life Sciences, Environmental science. Södertörn University, School of Life Sciences, Biology.
    Porsch-Hällström, Inger
    Södertörn University, School of Life Sciences, Environmental science. Södertörn University, School of Life Sciences, Molecular biology.
    Hallgren, Stefan
    Södertörn University, School of Life Sciences, Environmental science. Södertörn University, School of Life Sciences, Biology.
    Brain circuit imprints of developmental 17α-ethinylestradiol exposure in guppies (Poecilia reticulata): Persistent effects on anxiety but not on reproductive behaviour2012In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 178, no 2, p. 282-290Article in journal (Refereed)
    Abstract [en]

    The effects of endocrine disruptors may vary with the timing of exposure. The physiological implications of adult exposure are present during and shortly after exposure while embryonic exposure can imprint changes manifested in adulthood. In this study, guppy (Poecilia reticulata) embryos were exposed to 2 ng/L and 20 ng/L of 17α-ethinylestradiol during development via the mother and reared in clean water from gestation until 6 months of age. As adults, fish exposed to 20ng/L during development showed significantly altered behaviour in the Novel Tank test, where anxiety is determined as the tendency to remain at the bottom upon introduction into an unfamiliar tank. 17α-ethinylestradiol treatment increased the latency time before swimming to the upper half of the tank and decreased the number of transitions to the upper half. In control females the basal stress behaviour responses were significantly higher than in males, as indicated by longer latency period and fewer and shorter visits to the upper half, supporting the importance of gonadal hormones for the behaviour. The anxiety increased, however, with treatment in both sexes, suggesting that the observed response is not entirely due to feminization of the males. Shoaling behaviour, analyzed as tendency to leave a shoal of littermates, was neither sex-differentiated nor changed by treatment. Also male reproductive behaviour, brain aromatase activity and testes histology, previously shown to respond to oestrogen exposure in adult guppy, were unaffected by the developmental treatment. This suggests that the stress system in the guppy is very sensitive to 17α-ethinylestradiol, which possibly causes an early organisational imprint on the brain circuit that regulates stress reactions.

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