Sex hormone binding globulin and free levonorgestrel index in the first week after insertion of Norplant implants.
Article Details
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Alvarez F, Brache V, Tejada AS, Cochon L, Faundes A
Sex hormone binding globulin and free levonorgestrel index in the first week after insertion of Norplant implants.
Contraception. 1998 Oct;58(4):211-4.
- PubMed ID
- 9866001 [ View in PubMed]
- Abstract
Levonorgestrel has an inhibitory effect on sex hormone binding globulin (SHBG). This decrease in SHBG leads to an increase in the free levonorgestrel index (FLI), which has a stronger biological effect. The interaction between serum levels of levonorgestrel and SHBG in long-term users of Norplant implants has been described. This study was designed to understand the same interaction immediately after the insertion of the implants, in a group of 16 women, sampled at 0 and 6 h and at 1, 3, and 7 days after Norplant implant insertion. Peak serum levonorgestrel levels were achieved at 24 h after insertion, remaining stable on day 3 and decreasing by > 10% by day 7. SHBG did not change during the first 24 h, but decreased by 19% and 60% on days 3 and 7, respectively. FLI more than doubled from day 1 to day 7 after insertion. The large decrease in SHBG and doubling of FLI is not followed by a similar reduction in levonorgestrel, which is hard to explain without an increase in the release rate of the steroid from the capsule.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Levonorgestrel Sex hormone-binding globulin Protein Humans UnknownInhibitorBinderDetails