Transcriptional profiling of cows granulosa cells comparing granulosa cells from superstimulated control cows with granulosa cells from superstimulated cetrotide treated cows. Abstract:In cow, follicular growth stimulation (FSH) followed by a 44h-68h coasting (no FSH) period has been shown to be beneficial for developmental competence of aspirated oocytes. This process has been optimized but the associated physiology is not perfectly understood. During the above treatment LH pulse frequency is basal as the animal are in the luteal phase. The goal of this study was to test the existence of a beneficial effect of basal LH pulses during competence acquisition. To answer to this question, LH pulses have been pharmacologically inhibited during the optimal coasting period with GnRH antagonists. Commercial milking cycling cows (n=5) were stimulated with 3 days of FSH followed by a coasting period of 68H, with and without cetrorelix injections. At the scheduled time, transvaginal aspirations of immature oocytes were performed, followed by IVF while follicular cells were pooled for each animal and were snap-frozen. Granulosa cells RNA was extracted amplified and hybridized on Embryogene bovine microarray slides. Data were normalized with Loess, and analyzed with Limma procedure. Follicle size group proportions and granulosa cell transcriptome were studied. (1) There was a significant reduction in >10mm diameter follicles with cetrorelix comparing to without treatment. (2) Transcriptome analysis reveals 724 tanscripts potentially regulated by basal gonadotropins before LH surge. Among this LH influenced gene group, 84 transcripts were positively associated to developmental competence. This work allows the identification of subpopulations of gene signals dependant from LH or not, and permits a better comprehension of the implication of basal LH in follicle growth and in competence acquisition process. Two-condition experiment, control vs cetrotide treated cows. Biological replicates: 3 control cows, 3 cetrotide treated cows. Dye swap experiments, two colors, one replicate per array. Please note that the 'characteristics: Time' values represent the duration between the last FSH injection and the ovum pick up.