DOWN-REGULATION BY PROGESTERONE OF CFTR EXPRESSION IN ENDOMETRIAL EPITHELIAL-CELLS - A STUDY BY COMPETITIVE RT-PCR

To determine the effect of progesterone on the CFTR mRNA level in glan dular epithelial cells of guinea-pig endometrium, a competitive RT-PCR was developed using as an internal standard a competitor with the sam e sequence as CFTR RNA except for a 20 nucleotide insertion. Using thi s method, the results showed that the CFTR mRNA level decreased in cel ls treated with estradiol plus progesterone compared to cells receivin g estradiol alone. The decrease in CFTR mRNA level was maximal at 12 h incubation and was 27.3% of the CFTR mRNA level in estradiol-treated cells. The effect of progesterone was mimicked by the progestagen, R50 20 and was inhibited by antiprogestins, RU 38,486 and ZK 98,299. Resul ts ate discussed in relation to the changes taking place in the endome trium in preparation for implantation of the embryo. (C) 1995 Academic Press, Inc.