Plasma levels of cortisol and corticosteroid binding globulin during use of Norplant-2 implants.
Plasma levels of cortisol and corticosteroid binding globulin (CBG) were studied during one year in eleven healthy women using NORPLANT-2 implants. NORPLANT-2 implants release approximately 50 ug of levonorgestrel/day. A significant diurnal variation of cortisol levels was found during the study. No significant change in cortisol levels compared to pretreatment levels was found. Levels of CBG showed no diurnal variation, but decreased significantly during use of the implants. This was most probably due to a direct effect of the levonorgestrel, as the levels of estradiol did not change compared to pretreatment levels, except for the values after 6 months that were significantly lower than pretreatment levels. A "free cortisol index" calculated as: level of cortisol/level of CBG, was unchanged during treatment compared to pretreatment levels. It is concluded that although CBG levels were reduced, no significant change in cortisol patterns was seen during use of the implants.
D000328:Adult; D003692:Delayed-Action Preparations; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D016912:Levonorgestrel; D009644:Norgestrel / Q000008:administration & dosage; D014156:Transcortin / Q000032:analysis*
D003692:Delayed-Action Preparations; D009644:Norgestrel; D004958:Estradiol; D016912:Levonorgestrel; D014156:Transcortin; D006854:Hydrocortisone