Einfluss von androgenen auf die geschlechtsdifferenzierung verschiedener cichliden (teleostei)

Hackmann, Eva

doi:10.1016/0016-6480(74)90140-3

Cited by 14 publications

(7 citation statements)

References 23 publications

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“…The treatment caused a precocious development of male secondary sexal characters whereas it induced an ovarian differentiation in genetic males which followed an essentially similar process of development to that seen in normal females. Similar gonadal feminization paradoxically elicited by androgens proved to occur in several cichlids such as Tilapia mossambica, T. heudeloti, and Cichlasoma biocellatum (Hackmann 1974). In T. mossambica, according to Hackmann (1974) methyltestosterone and testosterone propionate at the concentration of 500 µg/L water provoked an oogenesis at admittedly high ratios in treated fish when given through the period of sex differentiation, though the treatment rather exerted an inhibitory influence of the gonadal development especially when the treatment with methltestosterone lasted long.…”

Section: Discussionmentioning

confidence: 65%

Morphological and Physiological Studies on Gonadal Sex Differentiation in Teleost Fish

Nakamura¹

2013

Aqua-BioSci. Monogr. (ABSM)

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Over the past 40 years, gonadal sex differentiation in teleost fish has been studied from histological and physiological viewpoints, for its application in fisheries. The morphological characteristics of gonadal sex differentiation in teleost fish were discussed in Section 2, and a summary of sexual processes, such as gonadal sex differentiation and sexual maturation in triploid salmonid fishes, was given. Subsequently, the effects of sex hormones/steroidal analogues on sex differentiation in several fish were examined. It was concluded that there is a critical period during physiological sex differentiationbefore morphological sex differentiation-in which the induction of artificial sex reversal by exogenous sex hormones can occur. It was also demonstrated that endocrine environmental disruptors have the potential to induce sex reversal in genetic males. In Section 3, it was clarified that ultrastructural steroid-producing cells appeared in the gonads of tilapia around the time of sex differentiation, indicating that endogenous steroid hormones play an important role during sex differentiation in fish. In Section 4, the expression of various steroidogenic enzymes including aromatase was immunohistochemically proven to occur in the gonads during the period of morphological ovarian differentiation in genetically female tilapia. In contrast, there was no expression in the gonads during differentiation, or in early testicular differentiation in genetically male tilapia. Aromatase inhibitor induced sex reversal from females to phenotypic males in tilapia and golden rabbitfish. It was also demonstrated that androgen treatment suppressed the expression of steroidogenic enzymes in the gonads of genetic females, and induced sex reversal. It was concluded that endogenous estrogen functions as an ovarian inducer, whereas lack of estrogen induces testicular differentiation.

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Section: Discussionmentioning

confidence: 65%

Morphological and Physiological Studies on Gonadal Sex Differentiation in Teleost Fish

Nakamura¹

2013

Aqua-BioSci. Monogr. (ABSM)

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“…Aggressive displays and fighting between male fish are common, even if it is costly from a metabolic point of view (Haller and Wittenberger, 1987;Alton et al, 2012). Male fish produce the endogenic androgen 11-ketotestosterone, responsible for male characteristic development and maintenance (Hackman, 1973). The blood concentration of this hormone rises in aggressive interactions and lowers in non-aggressive interactions (Francis et al, 1993).…”

Section: Social Housing and Other Exposure To Conspecificsmentioning

confidence: 99%

Mogelijke welzijnsproblemen bij de Siamese kempvis (Betta splendens) in sierviswinkels en bij de hobbyist

Pleeging¹,

Moons²

2017

Vlaams Diergeneeskundig Tijdschrift

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Betta splendens is an extremely popular ornamental fish among hobby aquarists. It has an interesting behavioral repertoire, particularly where male aggression and territoriality are concerned. The lack of scientific studies investigating optimal housing conditions in combination with the wide variety of commercially available husbandry products, raises questions about the welfare status of these fish in captivity. In this article, an overview of the available literature on the biology of the betta and general considerations of ornamental fish keeping is given, and environment- and animal-related factors with potential impact on the welfare of Betta splendens are examined. Although more research using biological and physiological indicators is needed, the following factors constituting welfare problems have been identified: an aquarium of limited dimensions, prevalence of Mycobacterium spp. infection, aggression to and from conspecifics or other species in the same aquarium and the limited ability to escape, potential for stress due to prolonged visual contact between males in shops and during shows, and the lack of environmental enrichment in the form of sheltering vegetation.

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“…Several causes have been proposed to explain this phenomenon (Hackmann 1974): a) aromatization of the exogenous androgen to estrogen, b) inhibition of the biosynthesis of the endogenous androgen in genetic males, resulting in ovarian differentiation, presumably because the exogenous androgen would cause a disturbance of somatic cells that are the source of the putative male sex inducer in the future testis (Nakamura 1978). The first hypothesis seems plausible.…”

Section: Introductionmentioning

confidence: 97%

Dosage-dependent differences in the effect of aromatizable and nonaromatizable androgens on the resulting phenotype of coho salmon (Oncorhynchus kisutch)

Piferrer

Donaldson

1991

Fish Physiol Biochem

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This study was conducted to investigate whether aromatization to estrogen could be the cause for the paradoxical feminization of gonads of sexually-undifferentiated fish after treatment with androgen at either high doses or for long periods. The aromatizable androgen 17α-methyltestosterone (MT) and the nonaromatizable androgen 17α-methyldihydrotestosterone (MDHT) were administered to groups of newly hatched coho salmon (Oncorhynchus kisutch) in a single 2h immersion at concentrations ranging from 6.25 to 6,400µg/l. The effects of treatment were evaluated by determining the resultant proportion of males in each experimental group. The effects of steroid administration on the final mean weight, length and condition factor were also determined. An increase in all these three variables was observed in the groups treated with the higher doses of MT. Regarding the resultant sexual phenotype, the response to both androgens was similar at the majority of doses tested. However, at the highest dose, the proportion of females increased with respect to that of males for MT, but not for MDHT. Since the major difference between the two androgens tested is their capacity to be aromatized, it seems that aromatization to estrogen, rather than inhibition of the biosynthesis of endogenous androgen, may explain the paradoxical feminization encountered.

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Einfluss von androgenen auf die geschlechtsdifferenzierung verschiedener cichliden (teleostei)

Cited by 14 publications

References 23 publications

Morphological and Physiological Studies on Gonadal Sex Differentiation in Teleost Fish

Morphological and Physiological Studies on Gonadal Sex Differentiation in Teleost Fish

Mogelijke welzijnsproblemen bij de Siamese kempvis (Betta splendens) in sierviswinkels en bij de hobbyist

Dosage-dependent differences in the effect of aromatizable and nonaromatizable androgens on the resulting phenotype of coho salmon (Oncorhynchus kisutch)

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