Expression of prolactin-releasing peptide in human placenta and decidua

The aims of this study were to determine whether the human placenta and dec idua express PRL-releasing peptide (PrRP) mRNA and whether PrRP regulates P RL secretion from cultured human decidual cells. PrRP gene expression was a nalyzed by reverse transcription (RT)-PCR, and the level of the gene expres sion was quantified by a ribonuclease protection assay. PrRP gene expressio n was detected in both the placenta and decidua. These tissues expressed Pr RP mRNA throughout pregnancy and the level of PrRP mRNA expression somewhat increased during midpregnancy. Placental and decidual cells also expressed PrRP mRNA, in vitro. To determine whether PrRP affects decidual PRL secret ion, human endometrial stromal cells and decidual cells were cultured and t reated with or without I muM PrRP31. PrRP31 did not affect PRL secretion in either short or longterm incubation. Moreover,the RT-PCR analysis indicate d that human decidua does not express the PrRP receptor, hGR3, mRNA. These findings suggest that PrRP produced by the human placenta and decidua does not affect decidual PRL secretion due to a lack of the receptor, and that i t may play other roles during pregnancy.