GROWTH HORMONE RECEPTOR TYPE I: FUNCTIONAL STUDIES DURING ZEBRAFISH EMBRYONIC DEVELOPMENT

CECILIA DI PRINZIO; MATÍAS CARNEVALE; SILVIA ARRANZ

Madrid

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

Asociación Ibérica de Endocrinología Comparada - Universidad Complutense de Madrid

The pleiotropic 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 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 this protein expression we performed fluorescent immunohistochemistry of 24 hpf and 48 hpf whole embryos. Ubiquitous expression of GHRa was observed in this embryo, with prevalence of this in the trunk, notochord and head regions, which is consistent with that observed by in situ hybridization experiments performed previously in our laboratory. Targeted knockdown of GHRa using to types of antisense morpholino oligonucleotides will let us do a functional approach of GHRa during early embryonic development. These data provide novel insights into GHRs roles during embryonic development and the maternal characteristic of GHRa protein suggest an important role of this binding protein at early life of fish, probably related to hardly known functions.