HEMMUNG DER UTERUSWIRKUNG VON OXYTOCIN DURCH GESTAGENE

Abstract

ABSTRACT In vivo Assays: Oil and water-soluble steroids have been investigated for their oxytocin-antagonism in pregnant rabbits treated with oxytocin. The uterine immobilizing effect is more marked after treatment with hydroxyprogesterone-derivatives than following the administration of 19-nor-testosterone-derivatives. In vivo investigations on the latent period show the following: after intramuscular administration of a micro-crystalline suspension, the latent period is 2–3 hours and is at least three hours following the administration of an oily solution. The maximum activity of the oily solution is obtained after 6 hours at the earliest and this occurs even later following the administration of the micro-crystalline suspension. There is no difference in latent period between the intravenous and intramuscular administration of micro-crystalline suspension. The water-soluble progestational agents examined in in vivo tests are 17-hemi-sulphate-esters of various 17α-hydroxyprogesterone-derivatives, Except for one compound* it was possible to prevent the oxytocin induced abortion with all substances in vivo. However, to achieve the inhibitory effect, very high doses of the water-soluble progestational agents were required. The duration of activity of these substances is limited to 2–3 hours. In vitro Assays: In addition, the water-soluble compounds were, with one exception also tested in vitro on the isolated rat uterus. It was possible to suppress the oxytocin-induced single contraction of the rat uterus.