Identification of prostaglandin E2 receptor sites in the embryonic murine palate

This study reports the existence and characteristics of prostaglandin E2 (PGE2) receptor sites during development of the murine embryonic palate. A radioligand binding technique utilizing [3H]-PGE2 was employed in the identification and characterization of binding sites. On day 13 of gestation, palatal PGE2 receptor sites were saturable (at 3.5 nM [3H]-PGE2) with high affinity (KD 1.6 nM) and low capacity (0.018 fmole/mg protein). Specific [3H]-PGE2 binding was completely reversible by 30 min. The rank order of prostanoid binding affinity at specific PGE2 binding sites was: E2 greater than F2 alpha greater than A2 greater than E1 = D2. The ability of embryonic palate mesenchymal cells to respond to PGE2 with dose-dependent accumulations of intracellular cAMP demonstrated the functional nature of these binding sites. Analysis of palatal PGE2 receptor characteristics during the period of palatal development also indicated significant temporal alterations in both receptor affinity and density.