Gonadotropin and estradiol secretion during the week of placebo therapy in oral contraceptive pill users.
The changes in the hypothalamic-pituitary-ovarian axis during the placebo week in oral contraceptive pill users were assessed. Fifteen women using the combined oral contraceptive pill were studied for eight hours at the start and at the end of the placebo week and gonadotropin secretion and estradiol concentrations were compared with those in control women in the follicular phase of an unmedicated menstrual cycle. Both gonadotropin and estradiol concentrations were suppressed at the start of the placebo week. By day 7 of placebo, gonadotropin concentrations and pulse patterns were indistinguishable from those of the control subjects although estradiol concentrations were still significantly lower.
van der Spuy
Z M
ZM
Department of Obstetrics and Gynaecology, University of Cape Town Medical School, Observatory, South Africa.
Sohnius
U
U
Pienaar
C A
CA
Schall
R
R
D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D004958:Estradiol / Q000378:metabolism*; D004997:Ethinyl Estradiol / Q000627:therapeutic use; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D005498:Follicular Phase / Q000187:drug effects; D006062:Gonadotropins / Q000378:metabolism*; D006801:Humans; D016912:Levonorgestrel; D007986:Luteinizing Hormone / Q000378:metabolism; D009644:Norgestrel / Q000627:therapeutic use; D010053:Ovary / Q000187:drug effects; D010507:Periodicity; D010919:Placebos
D003277:Contraceptives, Oral, Combined; D006062:Gonadotropins; D010919:Placebos; D009644:Norgestrel; D004997:Ethinyl Estradiol; D004958:Estradiol; D016912:Levonorgestrel; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone