Figure 1. Prostaglandin H₁ (PGH₁) fully activates CRTH2 in living CRTH2-HEK cell transfectants.

A–E, abilities of PGH₁, selected prostaglandins, and the PGH₁ precursor dihomo-γ-linolenic acid (DGLA) to stimulate CRTH2 signaling using dynamic mass redistribution (DMR) technology. Cells were challenged with increasing concentrations of the indicated ligands and DMR was recorded as a measure of receptor activity (representative optical traces). F, transformation of optical traces (A–E) into concentration effect curves. Molar log EC₅₀ values were PGH₁: −6.37±0.12; PGH₂: −7.09±0.08; PGD₁: −6.92±0.16; PGD₂: −7.95±0.09 (mean values ± SEM, n = 3).