Studies on the Biological Action of 19-Norsteroids

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Various biological activities of 19-Norsteroids, Methyl 19-Nortestosterone (MNT), Ethinyl 19-Nortestosterone (EtNT), Ethyl 19-Nortestosterone (ENT), 19-Nortestosterone (NT) and their esters were investigated. 1) Androgenic activity : According to Eisenberg and Gordan's test, 19-Norsteroids corresponded to 1/1C-1/20 of Testosterone propionate (TP). Ethinyltestosterone (ET) was the weakest (1/40 of TP) and MNT was a little stronger than EtNT. 2) Anabolic activity : By means of Eisenberg and Gordan's test, they corresponded to 1/5-1/20 of TP in anabolic activity, ET was the weakest (1/40 of TP). EtNT was a little weaker than MNT, where as NT was equal to TP, ENT was the strongest among them (1/2, 5 of TP). 3) Estrogenic activity : On Allen-Dolsy test, they corresponded to 1/1,000-1/4,000 of Estradiol (OH2) in estrogenic activity, EtNT was two times stronger than MNT. In uterotrophic activity on Lauson's test, thay had only 1/3,000-1/40,000 of action of OH2. EtNT was the strongest of all. 4) Progestational activity : On Clauberg test by injection they corresponded to 1/2-1/30 of Progesterone (P). MNT and EtNT was 1/30 of P. By oral administration they were distinctly activer than ET, in fact at least two-ten times. Both MNT and ENT were ten times activer than ET. As for the duration of Clauberg's progestational action following a single injection of 20mg. their esters were stronger than free compounds. The effects of both MNT-enanthate (MNTE) and EtNT-enanthate (EtNTE) were recognized even on 10th day after injection. 5) Inhibiting activity on pituitary gonadotrophic potency : Of inhibiting activity on pituitary gonadotrophic potency by testes weight decrease test in rats, EtNT was the strongest of others, MNT and their esters were not so active. By means of gonadotrophic potency test in mice following injection with 19-Norsteroids, EtNT inhibited its action and was the strongest of all. 6) Pregnancy maintenance activity : Activity in Clauberg test and pregnancy maintenance effect in rats were not always pararrel. The 19-Norsteroids were all quite active in even if given by mouth, but pregnancy maintenance effect was rather weak. On Clauberg test 19-Norsteroids were generally stronger when given by mouth than by injection, while in pregnancy maintenance actlvity parenteral application was better than peroral treatment. 7) Effect on sexual cycle of rats : MNT and EtNT inhibited the estrus when given for a long time. In generally the sexual cycle became irregular. 8) Chemical structures and biological activities : There seemed to exist a definite relation between the chemical structures and the biological activities of 19-Norsteroids.