Professor Zvi Naor from Tel-Aviv University was one of the scientists who discovered GnRH, which releases the sex hormones in the brain (the feedback is presented in page 16). In an interview from 1989, on the journal "Mada" ("Science") he tells about the shortcomings of the current contraceptives, based on Estrogen and Progesterone. Professor Naor suggests using new contraceptives that will be based on blocking GnRH receptors. In his opinion, such blocking can be a better and healthier alternative. 1 Fifteen years passed since that interview in "Mada" and in our medicine cabinet today we have GnRH agonists (suppressing agents), stopping the activity of the reproductive system. This is a family of drugs disrupting the signals sent from the Hypothalamus to the Pituitary Gland. Doctors recommend this treatment today for cases of early sexual maturity with menstruation in young girls. Using GnRH agonists is also recommended for patients suffering heavy bleeding from the womb wall, and in cases of Endometriosis, a disease characterized by growth of cells in the womb wall. Using GnRH agonists is not exclusive to women; men with prostate cancer are also treated with them. It is important to note that the present medications are prohibited for long term use since they can cause bone density loss, causing Osteoporosis.
A group of researchers from the Oregon Regional Primate Research Center is doing experiments with "ZK 230211", a Progesterone-receptor antagonist. It prevents ovulation as well as building of excessive tissue in the womb. The pilot studies in Rhesus female monkeys were completed with great success. Using the receptor antagonist stopped menstruation – with no bone density loss – and fertility returned to normal about two weeks after stopping its use. The researchers say that the success of the experiment with female monkeys indicates a possibility for almost immediate implementation in women. 2
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