LEVELS OF CORTICOTROPIN-RELEASING HORMONE-RECEPTOR SUBTYPE-1 MESSENGER-RNA IN PREGNANCY AND DURING LABOR IN HUMAN MYOMETRIUM MEASURED BY QUANTITATIVE COMPETITIVE PCR

It is suggested that corticotrophin-releasing hormone (CRH) is involve d in parturition. We have previously reported the presence of the CRH receptor subtype 1 (CRH R1) in human uterine myocytes. The aim of the present study was to investigate whether expression of the CRH R1 in m yometrial tissue changes in pregnancy and labour. We used a quantitati ve competitive PCR method to measure the mRNA levels of this receptor in non-pregnant and in term pregnant myometrium before and at differen t stages of labour. The levels of mRNA for the housekeeping gene for g lucocerebrosidase (GCB) were also determined. The results were express ed as a ratio of CRH R1 and GCB mRNA levels. We have found that in pre gnancy the CRH R1 is down-regulated from a ratio of 0.093 +/- 0.011 in non-pregnant myometrium to 0.012 +/- 0.005 (P<0.001) in term non-labo uring myometrium. No significant changes were observed in the CRH R1:G CB ratio in tissues sampled within 13 h (0,013 +/- 0.004) from the sta rt of labour. In summary, normalised levels of CRH R1 are down-regulat ed in pregnancy and do not change during labour. We speculate that our results do not support a direct role for the CRH R1 receptor in myome trial stimulation.