[Serum 17-beta-hydroxysteroid dehydrogenase activity in prostaglandin abortion].

The 17 beta-HSD-activity and the classical hormonal parameters (HCG, HPL, P, E2 and E3) were determined in the serum of 8 pregnant women who received Sulproston (Nalador) intravenously for legal termination of pregnancy. The 17 beta-HSD-activity and the determined hormonal parameters showed opposite behaviour: while the latter were slowly decreasing, the activity of the 17 beta-HSD steeply increased when rhythmic labor started. This increase was also demonstrable when the fetus had died before the beginning of Sulproston infusion ("missed abortion"). The rise in 17 beta-HSD activity is therefore not dependent on a living fetus. In so-called "prostaglandin failures", where rhythmic uterine contractions could not be induced and no abortion occurred, this rise in activity was absent. It is therefore a reliable indicator for the success of Sulproston therapy and the irreversibility of its action. Sulproston probably activates the 17 beta-HSD in an indirect manner. This activation is directly correlated to the occurrence of rhythmic uterine contractions. Evidence is presented that this increase in enzyme activity is a specific accomplishment of the placenta. The labour dependent shift of steroid concentrations (E1/E2 and 20 alpha-DHP/P) in the placenta and adjacent myometrium, as proven by other authors, can be explained by the activation of the 17 beta-HSD. Thus, the 17 beta-HSD influences the concentrations of those steroid hormones which play an important role in the regulation of labour.