A conceptual framework for understanding sexual differentiation of the teleost brain

Okubo, Kataaki; Miyazoe, Daichi; Nishiike, Yuji

doi:10.1016/j.ygcen.2019.02.020

Cited by 20 publications

(13 citation statements)

References 101 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This difference may reflect the fact that teleosts are highly sexually labile across their lifespan. In teleosts, including medaka, altering the sex steroid milieu effectively lead to the reversal of sex-typical behavioural, neural and gonadal phenotypes, even in adulthood [41,42]. The pituitary, as well as the brain and gonad, may possess lifelong sexual lability in teleosts.…”

Section: Discussionmentioning

confidence: 99%

Androgen-dependent sexual dimorphism in pituitary tryptophan hydroxylase expression: relevance to sex differences in pituitary hormones

et al. 2020

Self Cite

View full text Add to dashboard Cite

Serotonin is a biogenic monoamine conserved across phyla that is implicated in diverse physiological and behavioural functions. On examining the expression of the rate-limiting enzymes in serotonin synthesis, tryptophan hydroxylases (TPHs), in the teleost medaka ( Oryzias latipes ), we found that males have much higher levels of tph1 expression as compared with females. This robust sexual dimorphism was found to probably result from the direct stimulation of tph1 transcription by androgen/androgen receptor binding to canonical bipartite androgen-responsive elements in its proximal promoter region. Our results further revealed that tph1 expression occurs exclusively in pro-opiomelanocortin ( pomc )-expressing cells and that the resulting serotonin and its derivative melatonin inhibit the expression of the pituitary hormone genes, fshb , sl and tshb . This suggests that serotonin and/or melatonin synthesized in pomc -expressing cells act in a paracrine manner to suppress pituitary hormone levels. Consistent with these findings and the male-biased expression of tph1 , the expression levels of fshb , sl and tshb were all higher in females than in males. Taken together, the male bias in tph1 expression and consequent serotonin/melatonin production presumably contribute to sex differences in the expression of pituitary hormones and ultimately in the physiological functions mediated by them.

show abstract

Section: Discussionmentioning

confidence: 99%

Androgen-dependent sexual dimorphism in pituitary tryptophan hydroxylase expression: relevance to sex differences in pituitary hormones

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…The current findings are also of interest in terms of the sexual lability of the brain in teleost fish. In teleosts, including medaka, experimental manipulations that alter the sex steroid milieu can lead to the reversal of sex-typical mating behaviors even in adulthood ( Okubo et al, 2019 ). That observation has been further extended by the present finding that treating adult female medaka with androgen readily induced male-typical aggressive behaviors.…”

Section: Discussionmentioning

confidence: 99%

Male-predominant galanin mediates androgen-dependent aggressive chases in medaka

Yamashita

Takeuchi

Hosono

et al. 2020

eLife

Self Cite

View full text Add to dashboard Cite

Recent studies in mice demonstrate that a subset of neurons in the medial preoptic area (MPOA) that express galanin play crucial roles in regulating parental behavior in both sexes. However, little information is available on the function of galanin in social behaviors in other species. Here, we report that, in medaka, a subset of MPOA galanin neurons occurred nearly exclusively in males, resulting from testicular androgen stimulation. Galanin-deficient medaka showed a greatly reduced incidence of male–male aggressive chases. Furthermore, while treatment of female medaka with androgen induced male-typical aggressive acts, galanin deficiency in these females attenuated the effect of androgen on chases. Given their male-biased and androgen-dependent nature, the subset of MPOA galanin neurons most likely mediate androgen-dependent male–male chases. Histological studies further suggested that variability in the projection targets of the MPOA galanin neurons may account for the species-dependent functional differences in these evolutionarily conserved neural substrates.

show abstract

“…The brain plays a vital role in regulating many systems, including the reproductive system. In mammals, particularly humans, the brain is sexually differentiated between males and females [30], while in a teleost the brain is also sexually differentiated, but has the ability to change and adapt. It is well understood that the brain regulates the reproductive system through the classical axis, the hypothalamus-pituitary-gonadal (HPG) axis.…”

Section: Brainmentioning

confidence: 99%

“…The brain is known to play an essential role in regulating many bodily systems in an organism, including the reproductive system. In teleost, the brain is sexually differentiated into a male and female brain, but has the ability to change and adapt [30]. Nonetheless, the role of the brain during sex determination and differentiation is poorly understood until today.…”

Section: Introductionmentioning

confidence: 99%

Sex Determination and Differentiation in Teleost: Roles of Genetics, Environment, and Brain

Rajendiran

Jaafar

Kar

et al. 2021

Biology

View full text Add to dashboard Cite

The fish reproductive system is a complex biological system. Nonetheless, reproductive organ development is conserved, which starts with sex determination and then sex differentiation. The sex of a teleost is determined and differentiated from bipotential primordium by genetics, environmental factors, or both. These two processes are species-specific. There are several prominent genes and environmental factors involved during sex determination and differentiation. At the cellular level, most of the sex-determining genes suppress the female pathway. For environmental factors, there are temperature, density, hypoxia, pH, and social interaction. Once the sexual fate is determined, sex differentiation takes over the gonadal developmental process. Environmental factors involve activation and suppression of various male and female pathways depending on the sexual fate. Alongside these factors, the role of the brain during sex determination and differentiation remains elusive. Nonetheless, GnRH III knockout has promoted a male sex-biased population, which shows brain involvement during sex determination. During sex differentiation, LH and FSH might not affect the gonadal differentiation, but are required for regulating sex differentiation. This review discusses the role of prominent genes, environmental factors, and the brain in sex determination and differentiation across a few teleost species.

show abstract

A conceptual framework for understanding sexual differentiation of the teleost brain

Cited by 20 publications

References 101 publications

Androgen-dependent sexual dimorphism in pituitary tryptophan hydroxylase expression: relevance to sex differences in pituitary hormones

Androgen-dependent sexual dimorphism in pituitary tryptophan hydroxylase expression: relevance to sex differences in pituitary hormones

Male-predominant galanin mediates androgen-dependent aggressive chases in medaka

Sex Determination and Differentiation in Teleost: Roles of Genetics, Environment, and Brain

Contact Info

Product

Resources

About