Figure 2. Relative expression of mRNA for key uterine genes.

Relative expression of mRNA for oxytocin receptor (OTR), prostaglandin F_2α receptor (FP), prostaglandin H synthase-1 (PGHS-1), PGHS-2, connexin 43 (Cx-43), inducible nitric oxide synthase (iNOS), oxytocin (OT), endothelin-1 (ET-1) and the endothelin-1 receptor isoform A (ET_A) in rat uterine tissues obtained from non-pregnant animals (NP; n = 10–14) and from pregnant animals at gestational day 16 (n = 5–6), day 17 (n = 6–7), day 18 (n = 4–5), day 19 (n = 6–10), day 20 (n = 8–22) or from gestational day 21 or 22, not in labour (NL; n = 10–14) or animals in active labour (AL; n = 9–10). Some animals were treated with a single subcutaneous injection of the antiprogestin RU486 on gestational day 15 and tissues collected 24 h later on day 16 (RU; n = 18). Within each mRNA group, excluding the RU486-treated animals group, data were assessed using one-way ANOVA and the bars with unique superscripts are significantly different (P < 0.05) from bars without overlapping superscripts. To determine the effects of the antiprogestin treatment, the treated animals were compared to the animals on gestational day 16 (both groups illustrated using grey bars). An asterisk denotes a statistically significant difference between these two groups using the two-tailed t test.