PROOPIOMELANOCORTIN-RELATED PEPTIDES IN FETOPLACENTAL STRUCTURES THROUGHOUT PREGNANCY

This study evaluates the presence of proopiomelanocortin(POMO).related peptides in four embryos and eight fetal pituitaries starting from 5 to 25 weeks of pregnancy. .Moreover, fetal membranes (amnion and chorion) were also investigated. Freshly collected samples were boiled in acetic acid to destroy enzymes, homogenized and aub- mitted to high performance liquid chromatography (linear gradient from 25 to 40% acetonitrile in 0.01 M HOI, in 15', 1.5 ml/min), The collected fractions were tested for the presence of p.lipotrophin (p.LPH), p.endorphin(p.EP), y.endorphin(y.EP) through: RIAs. p.EP and p•LPH were detected from 7 weeks of pregnancy while y.EP appeared later. Only the cephalic portion of the embryos contained the peptides where p.LPH predominates while no immunoreactivity was detected in the rostral one. In the fetal pituitary there is a progressive increase of y.EP according to the gestational age and both p.EP and p.LPH showed a trend toward constancy in the 15- 25 week range. Amnion and chorion contai n a significant amount of the three peptìdes. Their ontogenesis starts earlìerthan in the embryo; p.LPH or p.EP were detected at 5 weeks of pregnancy. In both tissues p.EP was higher in the first than in the second trimester. These data demonstrate a different pattern of POMO ontogeny and processing betweeri the con- ceptus and his environment. This suggests that the POMQ•related opiod system of the fetus and of fetal adnexes are independent of each other, possibly subserving to different functions,