EFFECT OF GONADOTROPIN-RELEASING-HORMONE AGONIST TREATMENT ON GROWTH-HORMONE SECRETION IN WOMEN WITH POLYCYSTIC OVARIAN SYNDROME

The suppression of the pituitary-gonadal axis by the administration of gonadotrophin-releasing hormone agonists (GnRH-a) is used occasionall y as an adjunct therapy with gonadotrophins for ovulation induction in women with polycystic ovarian syndrome (PCOS), A number of recent cli nical studies have suggested that women with polycystic ovaries (PCO) may have disturbances of normal growth hormone (GH) kinetics and alter ations in the GH/insulin-like growth factor (IGF)-I system, The purpos e of this study was to determine the effect of GnRH-a administration o n GH-releasing hormone (GHRH)-stimulated GH release in women with PCOS , Eight women with PCO and six control women were studied before and a fter 2 months of treatment with the long acting GnRH-a triptoreline (3 .75 mg monthly injections), GHRH was given as a single i.v. injection and blood samples for GH measurements were obtained at -15, 0, 30, 60, 90 and 120 min, The GH responses were expressed as the area under the curve (AUC) or the differences from the basal value (Delta(max)). The GH response to GHRH (mean +/- SEM) was lower in women with PCO (AUG 1 14.9 +/- 43.1 versus 206.2 +/- 28.7 ng/ml/120 min, P < 0.05 and Delta( max) 31.6 +/- 8.2 versus 49.4 +/- 5.8 ng/ml,P < 0.05), After treatment with the GnRH-a, the GH response to GHRH was significantly smaller th an before treatment in both groups (PCO AUC 34.6 +/- 9.0 ng/ml/120 min and Delta(max) 12.4 +/- 3.1 ng/ml; controls AUC 148.8 +/- 28.4 ng/ml/ 120 min and Delta(max) 31.2 +/- 6.1 ng/ml), but the PCO group had a si gnificantly smaller response, These data demonstrate that women with P CO have a reduced GH response to GHRH compared with normal controls an d that GnRH-a administration causes a further GH reduction in both gro ups, Women with PCO have a greater suppression of GH response to GHRH during treatment with GnRH-a, This suggests that a different level of sensitivity in the somatotrophic axis exists in PCOS.