Early and late hormonal responses to the microdose gonadotropin-releasing hormone agonist in normal menstruating women.
OBJECTIVE
To assess the effect of a microdose gonadotropin-releasing hormone (GnRH) agonist on the LH, FSH, and E2 secretion in normal menstruating women.


METHODS
Prospective study.


METHODS
Tertiary teaching hospital.


METHODS
Five normal menstruating women.


METHODS
Five microg of triptorelin was injected daily in 5 women for 7 days beginning from the cycle day 3. In the next cycle, the same amount of triptorelin was injected into the same women daily for 3 days.


METHODS
Serial serum FSH, LH, and E2 levels.


RESULTS
The FSH levels peaked (27.53 +/- 6.34 IU/L) after 5 hours, and the LH levels peaked (34.35 +/- 7.81 IU/L) by 4 hours. The increased gonadotropin levels persisted even after the second and third day of the GnRH-agonist injections, although the peak levels were not as high as observed with the first injection (19.56 IU/L in the second day, 9.15 IU/L in the third day for FSH; 32.18 IU/L in the second day, 13.59 IU/L in the third day for LH). The down-regulation of gonadotropins was established in 4 days. When the GnRH-agonist was administered for 7 days, the E2 level began to increase 6 days after the last injection. When the GnRH-agonist was administered for 3 days, the E2 level began to increase 3 days after the last injection.


CONCLUSIONS
Pituitary down-regulation could be achieved even with a microdose of GnRH agonist. The increased level of gonadotropins persisted for 3 days at this dose. The duration of the down-regulation was influenced by the duration of GnRH-agonist administration.
Park
Won I
WI
Eulji Medical Center, Eulji University School of Medicine, Seoul, South Korea. pwi3110@eulji.or.kr
Kim
S Samuel
SS
Chung
Hwa Ryung
HR
Shin
So Young
SY
Lee
Jin Yong
JY
D000328:Adult; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004334:Drug Administration Schedule; D004958:Estradiol / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008598:Menstruation; D009994:Osmolar Concentration; D011446:Prospective Studies; D013997:Time Factors; D017329:Triptorelin Pamoate / Q000008:administration & dosage*
D017329:Triptorelin Pamoate; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone