[The activity of L-cystine-aminopeptidase (oxytocinase) in the serum of pregnant women during intravenous application of oxytocin (author's transl)].

The oxytocinase levels have been tested prior to, during and after oxytocin challenge tests in 42 pregnant women. There was no relation between labour and the activity of the enzyme. There was no change in the activity during and after oxytocin infusion. Repeated challenge tests did not change these results. The use of the oxytocinase as a parameter of placental function is not influenced by oxytocin infusions.