@article{PAR00012383,
  title = {{N}euroendocrine gene expression reveals a decrease in dopamine {D}2{B} receptor with no changes in {G}n{RH} system during prepubertal metamorphosis of {S}ilvering in wild {J}apanese eel},
  author = {{J}eng, {S}. {R}. and {Y}ueh, {W}. {S}. and {P}en, {Y}. {T}. and {L}ee, {Y}. {H}. and {C}hen, {G}. {R}. and {D}ufour, {S}ylvie and {C}hang, {C}. {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}ilvering is a prepubertal metamorphosis preparing the eel to the oceanic reproductive migration. {A} moderate gonad development occurs during this metamorphosis from the sedentary yellow stage to the migratory silver stage. {T}he aim of this study was to elucidate the molecular aspects of various endocrine parameters of {BPG} axis at different ovarian developmental stages in wild yellow and silver female {J}apanese eels. {T}he {GSI} of the sampled female eels ranged between 0.18 and 2.3%, corresponding to yellow, pre-silver and silver stages. {G}onad histology showed changes from previtellogenic oocytes in yellow eels to early vitellogenic oocytes in silver eels. {B}oth serum {E}-2 and {T} concentrations significantly increased with ovarian development indicating a significant activation of steroidogenesis during silvering. {I}n agreement with previous studies, significant increases in pituitary gonadotropin beta subunits {FSH}-beta and {LH}-beta transcripts were also measured by q{PCR}, supporting that the activation of pituitary gonadotropin expression is likely responsible for the significant ovarian development observed during silvering. {W}e investigated for the first time the possible brain neuroendocrine mechanisms involved in the activation of the pituitary gonadotropic function during silvering. {B}y analyzing the expression of genes representative of the stimulatory {G}n{RH} control and the inhibitory dopaminergic control. {T}he transcript levels of m{G}n{RH} and the three {G}n{RH} receptors did not change in the brain and pituitary between yellow and silver stages, suggesting that gene expression of the {G}n{RH} system is not significantly activated during silvering. {T}he brain transcript levels of tyrosine hydroxylase, limiting enzyme of {DA} synthesis did not change during silvering, indicating that the {DA} synthesis activity was maintained. {I}n contrast, a significant decrease in {DA}-{D}2{B} receptor expression in the forebrain and pituitary was observed, with no changes in {DA}-{D}2{A} receptor. {T}he decrease in the pituitary expression of {DA}-{D}2{BR} during silvering would allow a reduced inhibitory effect of {DA}. {W}e may raise the hypothesis that this regulation of {D}2{BR} gene expression is one of the neuroendocrine mechanisms involved in the slight activation of the pituitary gonadotropin and gonadal activity that occur at silvering.},
  keywords = {{G}onadotropins ; {G}n{RH} ; {D}opamine ; {D}opamine {D}2 receptor ; {S}ilvering},
  booktitle = {},
  journal = {{G}eneral and {C}omparative {E}ndocrinology},
  volume = {206},
  numero = {},
  pages = {8--15},
  ISSN = {0016-6480},
  year = {2014},
  DOI = {10.1016/j.ygcen.2014.08.001},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00012383},
}