Plasma oxytocic activity after ovariectomy and stilboestrol or progesterone implantation in female rats.

Plasma oxytocic activity after ovariectomy and stillboestrol or progesterone implantation in female rats. Acta Physiol. Pol. 1977, 28 (2): 135--142. The purpose of this work was to compare the oxytocic activity of plasma in the intact rats, after ovariectomy, and in ovariectomized rats after subcutaneous implantation of stilboestrol or progesterone tablets. On the 22nd day after ovariectomy and implantation of hormones 2 ml of blood were obtained under urethane anaesthesia from the cephalad portion of the right external jugular vein. Plasma oxytocic activity was determined by the method of Van Dongen and Hays in Fragments of the rat mammary tissue at the time of lactation. The plasma oxytocic activity of ovariectomized female rats did not differ significantly from that found in the rats with implanted hormones. Cytological analysis of vaginal smears demonstrated stimulation of vaginal epithelium by exogenous hormones which lasted up to 10 days after implantation. Ovariectomy caused a threefold rise in the plasma oxytocic activity as compared with the control values.