Regulation of the human oxytocin receptor in the uterus: a molecular approach.

The oxytocin-oxytocin receptor (OTR) system plays important roles in the human uterus, and the effectiveness of oxytocin is greatly influenced by the pattern of receptor expression in vivo. To investigate OTR expression at the molecular level, we have established a bioassay system for the specific transcripts using Xenopus laevis oocytes, cloned the OTR cDNA, raised anti-OTR antibodies, and characterized OTR genomic clones and systems to study the transcriptional regulation of the gene. Using these molecular tools, we have examined OTR expression in the endometrium and myometrium of non-pregnant and pregnant women. OTR expression appears mainly to be regulated at the transcription level. Analysis of the 5' flanking region of this gene indicates constitutionally active promoter activity when transfected into cultured HeLa and SKN cells. We are currently developing these techniques to analyse OTR regulation in the uterus.