Xiao B L, Zhang X L, Feng D D
Contraception. 1985 Nov;32(5):455-71. doi: 10.1016/0010-7824(85)90016-2.
Pharmacokinetic and pharmacodynamic effects of a vaginal ring releasing 20 micrograms/day levonorgestrel (L-NOG) have been studied in 15 women. Serum levels of L-NOG, estradiol and progesterone were measured three times a week in a control menstrual cycle and a treatment period of 3 months after the insertion of the first vaginal ring. All control cycles were normal ovulatory. Among the 36 treatment cycles 13 were ovulatory (36%), 5 ovulatory with inadequate luteal function (14%), 14 anovulatory but with marked follicle activity (39%) and 4 anovulatory (11%). In the groups with ovulatory reaction the serum levels of L-NOG showed a decline of 54% of the initial level at the end of the treatment period, calculated according to the linear regression equation of Y = 0.903-0.0142X, while in the groups without ovulation the L-NOG levels were higher and the decline was 24% of the initial level (Y = 1.034-0.0086X). There were distinct individual differences in the levels of L-NOG and ovarian reactions. Marked follicle activity with very high estradiol levels were found in correlation with high L-NOG in 7 treatment cycles, particularly in the B type of reaction (B = anovulatory cycle with marked follicle activity). More intermenstrual bleeding and spotting occurred in the second treatment cycles, particularly in those with anovulatory reactions.
对15名女性研究了每日释放20微克左炔诺孕酮（L-NOG）的阴道环的药代动力学和药效学效应。在对照月经周期以及插入第一个阴道环后的3个月治疗期内，每周3次测量血清中的L-NOG、雌二醇和孕酮水平。所有对照周期排卵均正常。在36个治疗周期中，13个为排卵周期（36%），5个排卵周期但黄体功能不足（14%），14个无排卵但卵泡活动明显（39%），4个无排卵（11%）。在有排卵反应的组中，根据Y = 0.903 - 0.0142X的线性回归方程计算，治疗期末血清L-NOG水平下降至初始水平的54%，而在无排卵的组中，L-NOG水平较高，下降至初始水平的24%（Y = 1.034 - 0.0086X）。L-NOG水平和卵巢反应存在明显的个体差异。在7个治疗周期中，发现明显的卵泡活动且雌二醇水平非常高与高L-NOG相关，特别是在B型反应中（B = 无排卵周期但卵泡活动明显）。在第二个治疗周期中出现更多的经间期出血和点滴出血，特别是在无排卵反应的周期中。
