Characterization of PGE2 receptor subtypes in human eosinophils.

Although previous pharmacologic studies have indicated that PGE receptors are expressed in human eosinophils, the exact distribution of the subtypes remains mostly unknown. By using a combination of genetic and conventional pharmacologic approaches, coexpression of mRNAs encoding the PGE receptor 2 (EP2) and EP4 was confirmed in eosinophils. Moreover, competitive PCR analysis of eosinophil RNA revealed that levels of the EP4 receptor mRNA were significantly higher than those of the EP2 receptor mRNA (P =.04). On the basis of the expression levels of mRNAs, an EP4 agonist, but not an EP2 agonist, was effective in inducing cyclic AMP production in eosinophils, suggesting that the EP4 receptor is of primary importance in eosinophil functions of PGE(2).