Ratios of relative expression of mRNA for oxytocin receptor (OTR), prostaglandin F2α receptor (FP), prostaglandin H synthase-1 (PGHS-1), PGHS-2, connexin 43 (Cx-43), inducible nitric oxide synthase (iNOS), oxytocin (OT), endothelin-1 (ET) and the endothelin receptor isoform A (ETA) in myometrial and endometrial tissues from rats during late gestation. The endometrium was bluntly dissected from the uterine wall (n = 11) and the horizontal bars represent the quotients of the concentration of each mRNA in the myometrium divided by the concentration found in the endometrium from the same samples. Thus, transcripts with log ratios less than 0 are predominantly endometrial in origin and those with log ratios greater than 0 are predominantly from myometrium. The bars with unique lower case designations are significantly different from those without overlapping designations.