[Steroid metabolism in fetal membrane].

UNLABELLED

In vitro tissue culture and incubation studies were undertaken to study the enzymatic activities for steroidogenesis in human fetal membrane.

MATERIALS AND METHODS

Human fetal membrane obtained at term was separated to reflected amnion(RA), placental amnion(PA), chorion laeve(C) and decidua(D). I) Except for D, 5 x 5cm2 of the tissue were cultured in MEM medium with 10% FCS for 8 days. At steroid tracers, 14C-dehydroepiandrosterone(DHA), or 14C-DHA-sulfate(DHA-S) was added and half of the medium was changed every 2 days. II) 800 x g Cell free homogenate was incubated with radioactive DHA-S, pregnenolone-S(P-S) and estrone-S(E-S). Radioactive metabolites in the medium were extracted and identified.

RESULTS

Sulfatase activity was found not only in D and C but also in RA and PA. The accumulated products of DHA-S to DHA increased as the number of cultured days increased. Sulfokinase and 17 beta-hydroxysteroid dehydrogenase activities for DHA was also found when PA was cultured. From the results of the kinetic studies on incubation, E-S showed the highest affinity for sulfatase in all tissue. Kinetic studies for sulfatase activity in RA demonstrated that Km values for E-S and DHA-S were 33 and 66 microM, respectively.

CONCLUSION

This is the first report to demonstrate the activity of sulfokinase in RA and that of sulfatase in amnion membrane. These results provide further information on the function of fetal membrane which seems to play an important role in the transport and metabolism of steroids in the feto-placental compartment during pregnancy.