Objective  To evaluate the function of hypothalamus-pituitary-gonad axis (HPGA) in patients with polycystic ovary syndrome (PCOS) using gonadotropin-releasing hormone (GnRH) analogue (triptorelin) stimulation test and to investigate the changes of HPGA following triptorelin stimulation test.

  Methods  Triptorelin stimulation test was conducted in PCOS patients (n=20) and healthy controls (n=30). Serum levels of luteinizing hormone (LH) and follicular stimulating hormone (FSH) were measured at 0, 15, 30, 45, 60 and 90 minutes after intramuscular injection of triptorelin 100 μg in the test. LH and FSH levels and LH/FSH at baseline and after stimulation test were compared between the two groups.

  Results  The control group had a higher level of testosterone than the PCOS group(1.9±0.5)nmol/L vs. (3.5±1.4)nmol/L, P=0.012. Baseline LH in the PCOS group was higher than that in the control group(11.3±6.6)U/L vs. (3.7±2.7)U/L, P=0.028. After triptorelin stimulation test, LH in the PCOS group increased with a larger magnitude than the control groupat 15 min, (41.4±28.0)U/L vs. (24.7±19.0)U/L, P=0.036; at 60 min, (64.0±34.8)U/L vs. (44.8±22.5)U/L, P=0.060. Baseline FSH in the PCOS group and the control group were (4.6±2.0) and (4.9±1.6)U/L(P=0.467), respectively.FSH increased less in the PCOS group than in the control groupat 60 min, (9.9±4.0)U/L vs. (17.3±5.6)U/L, P=0.041. Baseline LH/FSH ratios in the PCOS group and the control group were 2.9±1.1 and 0.8±0.2 (P=0.023), respectively, which both increased after triptorelin stimulation test (6.5±1.3 vs. 3.1±0.9, P=0.038).

  Conclusions  PCOS patients demonstrate higher baseline LH and LH/FSH ratio, growing difference between LH and FSH levels and increasing LH/FSH ratio after triptorelin stimulation test, which indicate dysfunction of HPGA in PCOS patients.