Effects of clomiphene citrate on pituitary luteinizing hormone and follicle-stimulating hormone release in women before and after treatment with ethinyl estradiol.
OBJECTIVE
To evaluate the effects of clomiphene citrate (CC) on pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release in hypoestrogenic women and in the same women after treatment with ethinyl estradiol (EE2).


METHODS
The study was of a prospective nature and was conducted on selected patients.


METHODS
Volunteer women were studied in a tertiary care public hospital.


METHODS
The 10 patients studied were selected on the basis of hypogonadal status (menopause, premature ovarian failure, or gonadal dysgenesis and Turner phenotype) and no hormonal treatment.


METHODS
Gonadotropin-releasing hormone (GnRH) was continually infused at the dose of 0.2 micrograms/min for 4 hours before and after the use of CC and/or EE2.


METHODS
The study was performed with the objective of determining the effect of estrogen (E) levels on the action of CC on in vivo gonadotropin release.


RESULTS
In the presence of hypoestrogenic conditions, CC had no pituitary action. However, after EE2 treatment CC promoted greater FSH release and a significant inhibition of LH release from the pituitary.


CONCLUSIONS
Clomiphene citrate needs a basal E level to be able to act on the pituitary. In normoestrogenic states and under GnRH stimulation, CC preferentially promotes FSH release while presenting a predominantly inhibitory effect on LH release.
de Moura
M D
MD
Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
Ferriani
R A
RA
de Sá
M F
MF
D002996:Clomiphene / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011446:Prospective Studies
D002996:Clomiphene; D007987:Gonadotropin-Releasing Hormone; D004997:Ethinyl Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone