Caractérisation de voies impliquées dans la régulation neuroendocrine du métabolisme énergétique et de la reproduction chez l’huître creuse Crassostrea gigas

The pacific oyster Crassostrea gigas exhibits an annual cycle of reproduction, which occurs in the gonadic area, a mix tissue composed of germinal cells and storage cells that regress during gametogenesis. Neuroendocrine regulations implicated in the physiological balance linking these tissues are not well known. Neuropeptide Y/F, which regulates energetic balance in vertebrates and invertebrates, binds G protein-coupled receptors; five related receptors have been identified in C. gigas. They display a differential pattern of expression depending on reproductive stage, and a higher expression in starved animals, compared to fed animals. By reverse endocrinology, no binding of NPY/F to these receptors could be demonstrated, but one of the receptors specifically binds a family of neuropeptides (GXLFRFamide) encoded by a unique precursor, whose expression also varies depending on trophic conditions. Bisides, a GnRH-like neuropeptide has been identified in oyster, its precursor expression varies depending on reproductive stage, and is induced in fed animals, compared to starved animals, suggesting that Cg-GnRH plays a role in the synchronization of nutritive status with energy needs during reproduction. New neuroendocrine pathways have been identified in C. gigas. They seem to be implicated in the regulation of processes linked to nutrition, reproduction and/or energetic metabolism, which are strongly connected to summer mortalities of this species.