Reproduction Abstracts

In cow, lysophosphatidic acid (LPA) stimulated synthesis and secretion of luteotropic factors in ovary, which affected growth and development of ovarian follicles. Theca cells, among other components of ovarian follicle, play an essential role in ovulation, which depends on intrafollicular prostaglandin synthesis. In bovine reproductive tract, modulation of prostaglandin synthesis occurs under influence of LPA. Thus, the aim of this study was to determine possible correlation between LPA signaling and expression of genes involved in preovulatory follicular development and ovulation in theca cells in different types of ovarian follicles. Theca cells were separated from healthy, transitional and atretic ovarian follicles, based on intrafollicular estradiol:progesterone ratio. mRNA expression for enzymes responsible for LPA synthesis (ATX, PLA2), receptors for LPA (LPAR1–4) and factors involved in ovulation and preovulatory follicle development (PGES, DBI, BTC, TFG, RABGAP-1 and CD-36) were determined. Obtained results confirm the presence of LPAR1-4, PLA2 and ATX mRNA in theca cells in all examined types of follicles. We also detected follicle type-dependent mRNA expression of all examined factors involved in preovulatory follicular development and ovulation. Moreover, we found that LPAR2-4 and PLA2 mRNA expression was positively correlated with mRNA expression of PGES, DBI, BTC, TFG, RABGAP-1 and CD-36 in theca cells gained from healthy follicles. These results suggest that theca cells are the place of LPA synthesis and target of its action in all examined types of follicles. Correlations between mRNA expression for LPARs, PLA2 and factors participating in follicle development and ovulation indicate potential role of LPA in those processes in cow.