HEPES buffered media may induce prostaglandin release from macrophages in tissue culture.

On investigating the release of PGE2 from mouse peritoneal macrophages in tissue culture it was found that the spontaneous release of PGE2 was dependent on the culture conditions employed. The type of buffering of the medium was especially important. Using CO2- sodium bicarbonate buffers we observed little, if any, spontaneous release of prostaglandins (PGs) from macrophages, whereas in the presence of N-2-hydroxyethylpiperazine-N-2-ethane-sulfonic acid (HEPES) buffer in some cases a dramatic increase in PG release was observed.