CHORION-VILLOSUM DOES NOT EXPRESS PROGESTERONE-RECEPTORS AND ESTROGEN-RECEPTORS DURING THE FIRST-TRIMESTER OF PREGNANCY

First-trimester chorion villosum plays the key role in the development of human placenta and secretes a large number of hormones and hormone -related substances. To test whether progesterone and estrogen could h ave regulatory effects on first-trimester chorion villosum functions, we investigated the presence of progesterone receptor (PR) and estroge n receptor (ER) in 47 chorion villosum samples from patients who under went abortion during the first trimester of pregnancy. The study was c arried out using immunohistochemical methods, No ER and PR positivity was evidenced in the 47 chorion villosum samples examined, The possibi lity that progesterone and estrogen play a role in the regulation of c horion villosum functions should therefore be excluded.