Growth hormone response to growth hormone-releasing hormone stimulation in oligozoospermic patients.

OBJECTIVE: To evaluate the GH response to growth hormone-releasing hormone (GH-RH) stimulation in oligozoospermic men. SETTING: Outpatient Clinic of Andrology at the Fundación Puigvert and the Department of Clinical Chemistry, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. PATIENTS: Fifteen oligozoospermic patients and 15 normozoospermic fertile men matched for age and body mass index. INTERVENTION: Endocrine status was determined by assay of basal levels of gonadotropins (FSH, LH), T, E2, inhibin, and insulin-like growth factor I (IGF-I). Serum GH levels were measured before and after GH-RH administration. RESULTS: GH response to GH-RH was significantly greater in patients than in controls. There was a positive correlation between the GH response and IGF-I levels in oligozoospermic patients only. Regression analysis showed a significant negative association of GH peak with inhibin after controlling for IGF-I in oligozoospermic patients. CONCLUSION: The results indicate that there is an altered responsiveness of pituitary to GH-RH administration in oligozoospermic patients; this did not appear to be due to the influence of gonadal steroid levels but rather to inhibin or some related peptide.