The prostaglandin transporter PGT transports PGH2

Prostaglandin H2 not only serves as the common precursor of all other PGs, but also directly triggers signals (e.g. platelet aggregation), depending on its location and translocation. The prostaglandin carrier PGT mediates the transport of several prostanoids, such as PGE2, and PGF2α. Here we used PGT in the plasma membrane as a model system to test the hypothesis that PGT also transports PGH2. Using wild-type and PGT-expressing MDCK cells, we show that PGH2 uptake is mediated both by simple diffusion and by PGT. The PGH2 influx permeability coefficient for diffusion is (5.66 ± 0.63) × 10−6 cm/s. The kinetic parameters of PGH2 transport by PGT are Km = 376 ± 34 nM and Vmax = 210.2 ± 11.4 fmol/mg protein/s. PGH2 transport by PGT can be inhibited by excess PGE2 or by a PGT inhibitor. We conclude that PGT may play a role in transporting PGH2 across cellular membranes.