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Study of the molecular mechanism of progesterone and estradiol on the onset of puberty in Nellore heifers

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Juliane Diniz Magalhães
Total Authors: 1
Document type: Doctoral Thesis
Press: Pirassununga.
Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
Defense date:
Examining board members:
Luis Felipe Prada e Silva; Mario Binelli; Ed Hoffmann Madureira; Felipe Perecin; José Luiz Moraes Vasconcelos
Advisor: Luis Felipe Prada e Silva

The understanding of the molecular mechanisms by which nutrition, genetics and hormonal treatments affect the beginning of puberty is of great importance for developing strategies aiming to reduce the age at first calving, and therefore increase the slaughter rate in Nellore cattle. The effects of progesterone device and of endogenous estradiol on the molecular mechanisms controlling the attainment of puberty in Nellore heifers were investigated. Specifically, the molecular pathways of progesterone and estradiol were studied in the hypothalamus. Thirty five non-pubertal heifers, between 13 and 14 months of age, were divided into four treatment (nine or eight per treatment): P4 device without estradiol (SP), P4 device with estradiol (PE), without P4 device and without estradiol (SS), and without P4 device and with estradiol (SE). The heifers were fed after weaning until reach 295 ± 11 Kg, with water access. At the end of the hormonal treatments all heifers were slaughtered and the hypothalamus areas were harvested, processed and then also stored at -80°C. Total RNA of hypothalamus were extracted, treated with DNase I and submitted to cDNA synthesis for gene expression quantification by real time PCR (qRT-PCR). RNA samples were pooling to realize a comprehensive study of the effects of progesterone administration and endogenous estrogen on attainment of puberty by next-generation sequencing (RNA-Seq), in order to identify possible candidate genes in the hypothalamus. Genes diffentially expressed between hypothalamic areas and affected by treatments were found. (AU)

FAPESP's process: 11/06979-3 - Study of molecular mechanism of progesterone and estradiol on the onset of puberty in Nelore heifers.
Grantee:Juliane Diniz Magalhães
Support Opportunities: Scholarships in Brazil - Doctorate