Lähteenmäki P, Weiner E, Lähteenmäki P, Johansson E D, Luukkainen T
Contraception. 1982 Mar;25(3):299-306. doi: 10.1016/0010-7824(82)90053-1.
Three women received one subcutaneous SilasticR capsule containing 40 mg of ST-1435 for contraception. Plasma levels of ST-1435, a 19-norprogesterone derivative, were measured during the treatment period of 13-15 months. The effects of treatment on pituitary and ovarian function were determined by assaying plasma concentrations of LH, FSH, estradiol and progesterone. The mean concentrations of ST-1435 during the treatment varied from 52 to 220 pg/ml in different subjects. These low concentrations of progestin were sufficient to suppress ovulation and make the implant effective for more than one year. No mid-cycle gonadotropin peaks were observed during the treatment. The subjects showed constantly low estradiol levels, thus also indicating a suppression of follicle development. Regular cyclic activity of the pituitary and ovaries, without the occurrence of ovulation, was observed in one subject. Increasing levels of estradiol parallelled a decrease of FSH and LH. It therefore seems that the negative feedback action of estradiol on gonadotropin release is unaffected but the positive feedback action of estradiol on LH appears to be blocked by the progestin ST-1435.
三名女性接受了一枚皮下植入的含有40毫克ST-1435的硅橡胶胶囊用于避孕。在13至15个月的治疗期内，对19-去甲孕酮衍生物ST-1435的血浆水平进行了测量。通过检测血浆中促黄体生成素（LH）、促卵泡生成素（FSH）、雌二醇和孕酮的浓度，确定治疗对垂体和卵巢功能的影响。治疗期间，不同受试者的ST-1435平均浓度在52至220皮克/毫升之间变化。这些低浓度的孕激素足以抑制排卵，并使植入物在一年多的时间内有效。治疗期间未观察到周期中期促性腺激素峰值。受试者的雌二醇水平持续较低，因此也表明卵泡发育受到抑制。在一名受试者中观察到垂体和卵巢有规律的周期性活动，但未发生排卵。雌二醇水平升高与FSH和LH水平降低平行。因此，雌二醇对促性腺激素释放的负反馈作用似乎未受影响，但雌二醇对LH的正反馈作用似乎被孕激素ST-1435阻断。
