Changes in the transcriptome of bovine ovarian cortex during follicle activation in vitro

A key transition in ovarian follicular development is the activation of resting primordial follicles to the growing primary follicle stage. The signals that regulate activation are still not well understood, especially in non-rodent species. we combined a microarray approach with an in vitro system to gain insight into the regulation of follicle activation. Genes and pathways identified in this study provide interesting candidates for further investigation of mechanisms underlying follicle activation. Fetal bovine ovarian cortical pieces enriched for primordial or primary follicles were obtained by culture with cotrol medium supplemented with TS+ (transferrin, selenous acid, BSA, and linoleic acid) or with insulin (ITS+), a factor that stimulate bovine follicle activation. Total RNA was extracted. Differences in global gene expression profiles between pieces enriched for primordial or primary follicles were determined by microcarray analysis.