Gonadotropin pulsatility in a stimulated cycle: clomiphene citrate increases pulse amplitudes of both luteinizing hormone and follicle-stimulating hormone.
OBJECTIVE
To elucidate gonadotropin secretory patterns during ovarian hyperstimulation for in vitro fertilization.


METHODS
All volunteers who attended the unit during a period of 3 months were prospectively investigated.


METHODS
Infertility unit of the University Central Hospital of Oulu.


METHODS
Normally menstruating tubal infertility patients (n = 8) and healthy women with ovulatory cycles (hospital personnel, n = 11). All patients finished the study.


METHODS
Clomiphene citrate (CC), 50 mg, was administered on cycle days 5 to 9 and 300 IU of pure follicle-stimulating hormone (FSH) on cycle day 7 and 150 IU on cycle day 8.


METHODS
Serum samples for luteinizing hormone (LH) and FSH measurements were collected at 10-minute intervals for 6 hours on cycle day 7 (effect of CC) and day 9 (effect of CC/FSH), and the data were analyzed with the Munro computer program.


RESULTS
The number of LH peaks was identical in the controls and study subjects on cycle days 7 and 9, whereas the pulse amplitude (P less than 0.025) and the pulse area (P less than 0.01) were higher in the CC/FSH-treated patients. The increase in overall mean LH level during the hormone therapy was not significant. In the CC/FSH-treated women, a decreased number of FSH pulses (P less than 0.01) with increased amplitude (P less than 0.001) and pulse area (P less than 0.01) was found. Clomiphene citrate treatment increased the mean FSH level (control versus cycle day 7, P less than 0.05) which was further increased (cycle day 7 versus cycle day 9, P less than 0.05) by FSH administration on cycle days 7 to 8. Otherwise pure FSH was found to be unable to modify endogenous LH or FSH secretory patterns under these conditions.


CONCLUSIONS
Clomiphene citrate increases the amplitudes of both LH and FSH pulses in the midfollicular phase of a stimulated cycle, an effect which is not influenced by pure FSH administration.
Department of Obstetrics and Gynecology, University of Oulu, Finland.
H
H
Martikainen
L
L
Rönnberg
A
A
Ruokonen
A
A
Kauppila
D000328:Adult; D002996:Clomiphene / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism*; D010062:Ovulation Induction; D010507:Periodicity
D002996:Clomiphene; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone