Detection of EP mRNA in monkey oocytes. Products of the expected size were obtained by RT-PCR for EP1 (203 base pair (bp)), EP2 (253 bp), EP3 (251 bp), EP4 (228 bp), and β-actin (270 bp). Amplified product was not obtained when water was substituted for reverse transcribed monkey RNA. Position of DNA base pair standards shown on left (bp). Below gel, the number of oocyte preparations with detectable EP receptor mRNA is shown out of the total of 6 preparations tested; β-actin mRNA was detected in all 6 preparations tested.