[Pituitary response to GnRH analogue testing in girls with a polycystic ovary syndrome].

Abstract

Unlabelled: THE AIM of our study was to estimate the gonadotropin level after GnRH analogue injection in girls with PCOS after suppression with dexamethasone.

Material and methods: 57 girls with hirsutism, mean age 15.9 years, were involved in the study. The research was performed in the early and middle follicular stage. Menstrual disorders were observed in 78% of them. The patients were divided into 3 groups: I -- with clinical and laboratory symptoms of PCOS (menstruation disorders, testosterone >65 ng/ml and/or LH/FSH >2; n=29), II -- with menstruation disorders and without elevated androgen level (n=15), III -- without menstruation disorders and without elevated androgen level (n=13). Basal blood samples were drawn at 8 a.m. GnRH analogue (Relefact LH-RH) 100 microg was then given subcutaneously and blood samples were drawn every 4 hours for 24 hours.

Results: Basal level of LH was the highest in group I (6,18+/-4,10 IU/l) in comparison with II (5.53+/-3.40 IU/l) and III (3.82+/-2.79 IU/l). After GnRH analogue administration mean LH concentration increased in all groups and peaked after 2 hours. Stimulated LH level was the highest in group I and differed statistically significantly from group III during the whole period of the test. The most significant difference occurred at 12 a.m. (p=0.003) and 10 a.m. (p=0.004). The FSH secretion in all tested groups was similar. It peaked, like LH, after 2 hours after GnRH analogue injection and decreased slightly during next 2 hours. A marked decrease was observed in the following period of time.

Conclusions: 1. High and fast LH secretion responding to GnRH analogue indicates masculinization of the hypothalamo-pituitary axis in PCOS girls. 2. The hirsute girls without menstrual disturbances and hormonal abnormalities probably also have subtle masculinization of the pituitary response to stimulation by GnRH analogue.