LOCALIZATION OF PROLACTIN AND ITS RECEPTOR MESSENGER-RNA IN THE HUMANDECIDUA

Prolactin (PRL) is known as an anterior pituitary hormone. On the othe r hand, PRL is also produced in the human decidualized endometrium. Th e physiological role and site of action of endometrial PRL have not ye t been clarified. This study was designed to investigate the localizat ion of PRL receptor (PRL-R) gene-expressing cells in the human decidua lized endometrium using in situ hybridization histochemistry. Sense an d antisense S-35-labeled RNA probes for human PRL-R mRNA were hybridiz ed with cryostat sections of human decidua, which were obtained from p atients undergoing therapeutic abortion at 8-10 weeks of gestation. Hy bridization signals for PRL-R mRNA were seen over the decidual cells. No labeled cells were seen in the chorion, amnion, or trophoblast. Com paring the localization of PRL-R gene-expressing cells to that of PRL gene-expressing cells using adjacent sections, their distributions wer e quite similar. These results indicate that not only PRL but also PRL -R transcripts are located in the decidual cells.