The Anticonceptive and the Effect on Uterus of Ether Extract, 18312-J ofRicinus communis

The ether extract 18312-J of Ricinus communis seed (600 mg/kg and 1.2 g/kg) administered subcutaneously to rats possessed significant anticonceptive activity. The extract demonstrated an oestrogenic effect in immature ovariectomized rats and mice and was devoid of any antioestrogenic property. Furthermore, the extract did not induce a decidual response in oestrogen primed ovariectomized rats and did not inhibit deciduoma formation in rats treated with progesterone. Administration of 18312-J to rats significantly altered the activity profile of the uterine muscle with respect to the frequency and amplitude of contraction as well as decreased responsiveness to oxytocin, ergometrine, acetylcholine and transmural electrical stimulation (TNS, 1-20Hz). The anticonceptive effect of 18312-J may be due in part to a disturbance of the oestrogen/progesterone balance and as well as to a direct action on the uterus.