The Influence of Growth Factors on the Prostaglandin Synthesis in Cultured Rabbit Luteal Cells

Summary

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, PGF_2α, and progesterone was determined. TNF-α, IL-2, IGF-I, IGF-II, and EGF alone were not able to change significantly the production of either progesterone or PGE₂ and PGF_2α when compared with the controls. AA as the precursor of PG biosynthesis increased the production of PGE₂ and PGF_2α significantly (1.2-fold and 2.6-fold, respectively; p<0.05; p<0.01). AA together with EGF increasedthe level of PG more pronounced when compared with AA alone (1.5-fold for PGE₂, 5-fold for PGF_2α; 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 PGF_2α 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 PGE?₂/PGF_2α-ratio in the corpus luteum of rabbits. This mechanism seems to be independent from the progesterone synthesis.

Key words

Growth Factors - Prostaglandins - Cultured Luteal Cells - Rabbit