The equine chorionic gonadotropin (eCG) associated to hormonal protocols used for estrus synchronization and embryo transfer (ET) in the bovine corpus luteum (CL) causes molecular impacts that have not been totally elucidated yet. A previous study performed by our research group analyzed by microarray the effects of eCG on the gene expression profiles in the CL of donors cows submitted to superovulatory treatment and recipients submitted to follicular stimulation with eCG. It was observed that eCG causes changes in the expression of multiple genes, particularly those related to progesterone synthesis, metabolism, cell differentiation and proliferation and angiogenesis. We hypothesized that eCG regulates in a differential manner the expression of genes related to insulin signaling pathways, which is within the corpus luteum physiology, in an important hormone to progesterone production, as well as being central to glucose metabolism, energy source of luteal cells. To test this hypothesis, we will performed two experiments: the experiment 1 will be delineate from the identification of the genes related to insulin differentially expressed in the animals treated with or without eCG from a microarray analysis generated list (Access number: GEO GSE37844). These findings will be validated by real time PCR, western blotting and immunohistochemistry. In the experiment 2, a cell culture model will be used to analyze the direct effects of eCG on bovine luteal cells insulin signaling pathway components gene expression. Data will be analyzed by GraphPad Prism 4.0 program (GraphPad Software, USA). The results obtained from this study will provide important insights into the understanding of eCG-induced changes in the bovine CL as well as identifying new strategies to improve the ET programs efficiency.
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