Reproduction Abstracts

Mural granulosa cells participate in development and differentiation of ovarian follicle. In bovine reproductive system, LPA is involved in autocrine and paracrine signaling, through LPA receptors (LPAR)s. We demonstrated before that LPA modulated prostaglandin (PG) synthesis in uterus and ovary and stimulated estradiol (E₂) synthesis in granulosa cells in bovine follicle. As the ovarian follicle development and differentiation leading to oocyte ovulation depend on PGs, in the present study we examined possible link between LPA signaling and expression of genes involved in ovulation in mural granulosa cells in three different types of ovarian follicles. Granulosa cells were recovered from healthy, transitional, and atretic follicles, based on intrafollicular E₂: progesterone ratio. Transcription profiles of enzymes responsible for LPA synthesis (PLA2, ATX), four LPARs and factors involved in ovulation and preovulatory follicle development (PTGS2, PGES, DBI, BTC, TFG, RABGAP-1 and CD-36) were determined in the cells. We found mRNA expression for PLA2, ATX and LPARs in granulosa cells. We found dynamic profile of mRNA abundance for factors involved in ovulation and preovulatory follicle development in granulosa cells depending on the type of follicle. Positive correlations between mRNA expression for PLA2 and RABGAP-1, PLA2 and TFG as well as LPAR2 and BTC were detected in granulosa cells in healthy follicles. Summarising, granulosa cells are the place of LPA synthesis and action in the bovine ovarian follicle. Positive correlations between mRNA expression for LPA synthesizing enzymes, LPARs and factors participating in ovulation and preovulatory follicle development suggest LPA involvement in those processes in cow.