The role estrogens play in sex differentiation and sex changes of fish

Nakamura, Masaru; Bhandari, Ramji Kumar; Higa, Motoki

doi:10.1023/b:fish.0000030495.99487.17

Cited by 100 publications

(71 citation statements)

References 17 publications

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“…Our results suggest an earlier steroidogenic potential in female rainbow trout gonads in comparison with males and also a very specific potential for estrogen synthesis in differentiating ovaries. This is in agreement with the crucial role of estrogens proposed in ovarian differentiation in fish (Guiguen, 2000;Nakamura et al, 2003) and some other lower vertebrates (Pieau and Dorizzi, 2004). Whether estrogens are produced by gonads at these very early stages of ovarian differentiation remains, however, to be demonstrated in fish.…”

Section: Figsupporting

confidence: 89%

“…During this process, numerous approaches including classic morphological examination, immuno-histochemistry, analysis of steroidogenic enzyme gene expression, and experimental inductions of sex inversion have revealed that steroid hormones are likely to play a crucial role in gonadal sex differentiation in fish (Nakamura et al, 1998;Guiguen, 2000;Devlin and Nagahama, 2002). For instance, it is now well accepted that endogenous estrogens are among the main effectors able to trigger fish ovarian differentiation (Nakamura et al, 2003). Accordingly, it has been shown in two fish species, the rainbow trout, Oncorhynchus mykiss, and a tilapia, Oreochromis niloticus, that estrogen synthesis potentiality precedes morphological ovarian differentiation (Guiguen, 2000;Nakamura et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…For instance, it is now well accepted that endogenous estrogens are among the main effectors able to trigger fish ovarian differentiation (Nakamura et al, 2003). Accordingly, it has been shown in two fish species, the rainbow trout, Oncorhynchus mykiss, and a tilapia, Oreochromis niloticus, that estrogen synthesis potentiality precedes morphological ovarian differentiation (Guiguen, 2000;Nakamura et al, 2003). On the other hand, the role of androgens during testicular differentiation in fish is still a matter of debate.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the fact that androgenic treatments are able to induce a complete functionally phenotypic masculinisation of genetically all female populations (Liu et al, 2000;Devlin and Nagahama, 2002), the potential for androgen synthesis could not always be detected before testicular differentiation in teleost fish (Nakamura et al, 2003). For instance, in the Nile tilapia it has been suggested that androgen synthesis is absent during this process (Nakamura et al, 1998;Nakamura et al, 2003) whereas, in rainbow trout, some studies support the idea that endogenous androgens could drive testicular differentiation (Liu et al, 2000;Govoroun et al, 2001). However in rainbow trout these studies were carried out before the first sign of morphological go-nadal differentiation, and the expression of some genes was already sexually dimorphic at the earliest sampling point investigated, such as aromatase (cyp19a1) in females and 11␤-hydroxylase (cyp11b2.1) in males.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of early molecular sex differentiation in rainbow trout, Oncorhynchus mykiss

Vizziano

Randuineau²,

Báron³

et al. 2007

Developmental Dynamics

180

171

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Early differentiation in rainbow trout gonads was investigated by expression profiling and in situ hybridization (ISH). Expression of cyp19a1 and fst in females and sox9a1 in males were sexually dimorphic between 32 to 35 days post-fertilization (dpf). After 35 dpf, the differentiation proceeded with sexually dimorphic profiles for sox9a2, dmrt1, cyp11b2.1, amh in males and foxl2a, foxl2b, hsd3b1, inha in females. cyp17a1, cyp11a1, star, nr5a1b increased only after 40 dpf in both sexes with a slightly higher expression in females. cyp19a1 expression was localized in a cluster of somatic cells in the ventral side of female gonads, and sox9a2 and amh in somatic cells surrounding the germ cells, at 28 dpf and thereafter, both in male and female gonads. cyp11b2.1, cyp17a1, and cyp11a1 expressions were only detected in scattered somatic cells in males after 46 dpf. This confirms the early implication of cyp19a1 in trout ovarian differentiation and suggests that early testicular differentiation does not need androgen production. Developmental Dynamics

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Section: Figsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characterization of early molecular sex differentiation in rainbow trout, Oncorhynchus mykiss

Vizziano

Randuineau²,

Báron³

et al. 2007

Developmental Dynamics

180

171

View full text Add to dashboard Cite

show abstract

“…In general, high aromatase and E 2 levels promote the development of ovaries while low aromatase and E 2 levels or high androgen levels promote the development of testes (reviewed in Nagahama, 2000;Piferrer, 2001;Devlin and Nagahama, 2002;Nakamura et al, 2003). For example, treating gonadally undifferentiated fish with estrogens at an appropriate dosage and for an appropriate time length causes the development of ovaries and of a female phenotype, regardless of the sex determination system (reviewed in Piferrer, 2001).…”

Section: Gonadal Aromatase Activitymentioning

confidence: 99%

Brain and gonadal aromatase activity and steroid hormone levels in female and polymorphic males of the peacock blenny Salaria pavo

Gonçalves

Teles

Alpedrinha

et al. 2008

Hormones and Behavior

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In the peacock blenny Salaria pavo large males with well-developed secondary sexual characters establish nests and attract females while small "sneaker" males mimic female sexual displays in order to approach the nests of larger males and parasitically fertilize eggs. These alternative reproductive tactics are sequential, as sneakers irreversibly switch into nesting males. This transition involves major morphologic and behavioral changes and is likely to be mediated by hormones. This study focuses on the role of aromatase, an enzyme that catalyses the conversion of androgens into estrogens, in the regulation of male sexual polymorphism in S. pavo. For this, sex steroid plasma levels and aromatase activity (AA) in gonads, whole brain and brain macroareas were determined in sneakers, transitional males (i.e. sneakers undergoing the transition into nesting males), nesting males and females collected in the field. AA was much higher in ovarian tissue than in testicular tissue and accordingly circulating estradiol levels were highest in females. This supports the view that elevated AA and estradiol levels are associated with the development of a functional ovary. Transitional males are in a non-reproductive phase and had underdeveloped testes when compared with sneakers and nesting males. Testicular AA was approximately 10 times higher in transitional males when compared with sneakers and nesting males, suggesting high AA has a suppressive effect on testicular development. Nesting males had significantly higher plasma levels of both testosterone (T) and 11-ketotestosterone when compared with the other male morphs and previous studies demonstrated that these androgens suppress female-like displays in sneakers. In the brain, AA was highest in macroareas presumably containing hypothalamic nuclei traditionally associated with the regulation of reproductive behaviors. Overall, females presented the highest levels of brain AA. In male morphs AA increased from sneakers, to transitional males, to nesting males in all brain macroareas. These results suggest that the transition into the nesting male tactic is accompanied both by an increase in testicular androgen production and by a higher conversion of androgens into estrogens in the brain. The increase in androgen production is likely to mediate the development of male secondary sexual characters while the increase in brain AA may be related to the behavioral changes associated with tactic transition.

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Sexual Determination, Differentiation, and Gonadal Development

Dietrich

Krieger

2008

Histological Analysis of Endocrine Disruptive Effects in Small Laboratory Fish

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The role estrogens play in sex differentiation and sex changes of fish

Cited by 100 publications

References 17 publications

Characterization of early molecular sex differentiation in rainbow trout, Oncorhynchus mykiss

Characterization of early molecular sex differentiation in rainbow trout, Oncorhynchus mykiss

Brain and gonadal aromatase activity and steroid hormone levels in female and polymorphic males of the peacock blenny Salaria pavo

Sexual Determination, Differentiation, and Gonadal Development

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