PGE2 and angiogenesis.

The angiogenic capability of PGE2 was tested by implanting pellets of an ethylene vinyl acetate slow release polymer containing PGE2 on the chorioallantoic membrane of 8-day-old chicken embryos. Elvax pellets releasing approximately 0.2, 2.0, or 20 ng/day PGE2 were found to induce neovascular responses. In contrast, pellets releasing 2.0 or 20 ng/day of either PGA2, PGF2, or TXB2 did not appear to be angiogenic when compared with PGE2. These release rates of PGE2 are similar to those reported for a variety of tumors, activated macrophages, inflammatory exudates, and rheumatoid synovia, suggesting that PGE2 may be a key factor in various neovascular reactions.