We have found a specific binding protein for synthetic progestins 6,7-[3H]methyltrienolone (R1881) and 17,21-dimethyl-19-norpregna-4,9-diene-3,20-dione (R5020) and in the testis cytosol from three "sisters" with the complete form of the testicular feminization syndrome. The binding component sediments in the 8S region of sucrose gradients. It is saturable. The apparent affinity constant (Ka) for R5020 was determined in two cases and found to be 1.8 and 0.6 X 10(8) M-1. The number of binding sites calculated from Scatchard plots is relatively high: 572 and 826 fmol/mg protein. Competition studies indicate that this putative receptor is specific for natural and synthetic progestins but not for 5 alpha-dihydrotestosterone and cortisol. Similar progestin binding could not be found in normal human and rat testes.
Much has been written about the risks of PID to IUD users, but very little about the subsequent fertility status of these patients. Is tubal infertility increased in an IUD user who has been asymptomatic? Does the addition of copper make the device harmless? Was the Dalkon Shield so harmful in the nulliparous woman? Our study (89 and 90% follow-up after 12-14 years) of 200 Dalkon Shield and 142 TCu-200 users allows us to answer 'No' to the three previous questions. We conclude that wearing an IUD per se does not cause infertility since all our patients who had IUDs removed for intended pregnancy did become pregnant; the addition of copper per se does not make an IUD safer although it does make it more efficient; the Dalkon Shield used in nulligravidas was not more dangerous than other types of IUD.
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