The effects of phospholipase C on oestradiol and progesterone secretion in porcine granulosa cells cultured in vitro.

Abstract

Granulosa cells play important roles in the regulation of ovarian functions. Phospholipase C is crucial in several signalling pathways and could participate in the molecular mechanisms of cell proliferation, differentiation and ageing. The objective of this study was to identify the effects of phospholipase C on the steroidogenesis of oestradiol and progesterone in porcine granulosa cells cultured in vitro. Inhibitor U73122 or activator m-3M3FBS of phospholipase C was added to the in vitro medium of porcine granulosa cells, respectively. The secretion of oestradiol decreased after 2hr, 8hr, 12hr, 24hr and 48hr of treatment with 500nM U73122 (p<.05) and decreased after 2hr of treatment in the 500nM m-3M3FBS addition group (p<.05). The secretion of progesterone increased after 4hr of treatment with 500nM U73122 (p<.05) and increased after 2hr and 8hr of treatment in the 500nM m-3M3FBS addition group (p<.05). The ratio of oestradiol to progesterone decreased at each time point, except 8hr after the addition of 500nM U73122 (p<.05). The ratio of oestradiol to progesterone decreased after 2hr (p<.05) of treatment with 500nM m-3M3FBS. In genes that regulate the synthesis of oestradiol or progesterone, the mRNA expression of CYP11A1 was markedly increased (p<.05), and the mRNA expression of other genes did not change significantly in the U73122 treatment group, while the addition of m-3M3FBS did not change those genes significantly despite the contrary trend. Our results demonstrated that phospholipase C can be a potential target to stimulate the secretion of oestradiol and suppress progesterone secretion in porcine granulosa cells cultured in vitro, which shed light on a novel biological function of phospholipase C in porcine granulosa cells.