The influence of growth factors on the prostaglandin synthesis in cultured rabbit luteal cells.

Abstract

Isolated rabbit luteal cells from day 12 of pseudopregnancy were cultured with a variety of growth factors, hCG and arachidonic acid (AA) in serum-free culture medium for 96 hours. The time course of prostaglandin (PG) E2, PGF2 alpha, and progesterone was determined. TNF-alpha, IL-2, IGF-I, IGF-II, and EGF alone were not able to change significantly the production of either progesterone or PGE2 and PGF2 alpha when compared with the controls. AA as the precursor of PG biosynthesis increased the production of PGE2 and PGF2 alpha significantly (1.2-fold and 2.6-fold, respectively; p < 0.05; p < 0.01). AA together with EGF increased the level of PG more pronounced when compared with AA alone (1.5-fold for PGE2, 5-fold for PGF2 alpha; p < 0.05 and p < 0.005). The progesterone production of the cells remained unchanged during growth factor exposure. We conclude that EGF together with high amounts of AA is able to stimulate the PG biosynthesis in cultured rabbit luteal cells. Since the level of PGF2 alpha increases more pronounced than PGE2, an activation of the PGE2 9-ketoreductase may be possible. Therefore, EGF could be relevant as an additional regression factor controlling the PGE2/PGF2 alpha-ratio in the corpus luteum of rabbits. This mechanism seems to be independent from the progesterone synthesis.