Growth hormone receptor type I: functional studiesduring zebrafish embryonic development

DI PRINZIO, CECILIA; CARNEVALE, MATÍAS; ARRANZ, SILVIA

Madrid

Congreso; 8º Congreso de la Asociación Ibérica de Endocrinología Comparada; 2011

Asociación Ibérica de Endocrinología Comparada

Growth hormone (GH) is implicated in many physiological functions besides growth, such as energy mobilization, gonadal development, osmoregulation and immunity in fish. These actions are initiated by its binding to the GH receptor (GHR), localized on the cell membrane of target tissues. Although two GHRs have been characterized in many fish species, their functional characteristics, mechanisms of regulation and roles in embryonic development remain unclear. To approach these issues, we studied the expression patterns of GHRa during embryonic development in the model organism zebrafish (Danio rerio). Until present, there were no data on GHRa expression at the embryonic stages. Using polyclonal antibodies against zebrafish GHRa extracellular domain, developed in our laboratory, we determined, for the first time, that this protein is from maternal origin and its expression is maintained throughout the early and late embryonic development. To localize the GHRa protein in 24 hpf and 48 hpf embryos we performed whole mount fluorescent immunostaining protocols using antiGHRa antibodies. Expression of GHRa was observed in the trunk, notochord and head, which is consistent with that observed by in situ hybridization experiments previously performed in our laboratory. The maternal characteristic of GHRa protein suggests an important role of this receptor at early life of fish, probably related to hardly known functions. Targeted knockdown of GHRa with two types of antisense morpholino oligonucleotides will let us do a functional approach of GHRa and will provide novel insights into GHRs roles during embryonic development.