[Study on the metabolism of prostaglandin F2 alpha in human placenta (author's transl)].

The activity of 15-hydroxy prostaglandin dehydrogenase (15 OH-PGDH) was studied in the human placenta by the biochemical determination and enzyme histochemical technique. The placentae of 6-40 weeks of gestation were obtained from artificial abortion, spontaneous abortion and normal delivery. 1) The capability of prostaglandin metabolism in the placenta increased according to gestational age. 2) The relative potency of 15 OH-PGDH activity among different tissues was placenta villi greater than chorion greater than decidua greater than amnion. The enzyme histochemical technique has disclosed the same results. 3) The conversion rate of PGF2 alpha to 15-keto PGF 2 alpha was dominant in the maternal side rather than fetal blood vessel system in the perfusion experiment of placenta. 4) The strong activity of 15 OH-PGDH was mainly localized in the syncytiotrophoblasts of placenta villi. 5) The activity of 15 OH-PGDH decreased in the placenta of abortion. The decrease of this enzyme activity was not detected in the toxemia of pregnancy. It has been postulated that endogenous and exogenous prostaglandin, which possesses strong and multiple biological activity, increases in the pregnancy. The present results suggest that the prostaglandin metabolic system in the placenta has the important role in the continuity of pregnancy.