Differential production and uptake of dual vitellogenins in Japanese medaka (Oryzias latipes)

Hiramatsu N., Inoue M., Ideuchi H., Fujita T., Amano H., Matsubara T., Sullivan C.V., Hara A.

Date de parution: juillet 2008
Volume: 32
Number: 2 suppl.
Pagination: 260
Editeur: Société Française d’Ichtyologie
doi: https://doi.org/10.26028/cybium/2008-322SP-131

Differential production and uptake of two forms of vitellogenin (VgA/B and VgC) was verified in serum and oocytes, respectively, of Japanese medaka (Oryzias latipes). The ratio of the two types of Vg (VgA/B:VgC) in the serum of females varied with reproductive stage (range ~2:1-8:1). In males exposed to waterborne E2 for various durations or at various dosages, the induced Vg ratios were fairly constant (~2.4:1-3.4:1) except that VgC alone was detected after a very short (2 h) exposure to E2. An antiserum against VgC (a-VgC) immunostained yolk granules in pre-vitellogenic oocytes when no immunoreactivity was found by staining with a-VgA/B. Both antisera stained yolk globules in vitellogenic oocytes. The reproductive phase-specific differences between plasma levels of VgA/B and VgC likely reflect different rates of their hepatic synthesis and uptake by oocytes.

Mots-clés: Estrogen - Induction - Medaka - Uptake - Vitellogenin
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