Effects of human Growth Hormone (hGH) and Gonadotropins (Gn) on the testicular response to human chorionic gonadotropin (hCG) in prepubertal GH-deficient children

Abstract

To evaluate the role of hGH, plasma testosterone (T) and dihydrotestosterone (DHT) were measured before and 72h after an IM injection of hCG (1500 I.U./m2) in seven prepubertal GH-deficient children before and after three months of hGH therapy. There were no significant differences (P > 0.05) between basal and 72h plasma T levels (mean ± SE) before and after hGH (basal : 0.60 ± 0.15 nM vs 0.39 ± 0.08 nM; 72h : 4.02. ± 1.10 nM vs 4.17 ± 1.13 nM). Like for T, no significant differences were found for DHT. To evaluate the role of Gn, the testicular response to hCG of 11 GH- and Gn-deficient children was compared to that of 16 prepubertal boys with GH deficiency and intact Gn secretion. As shown in the Table, 72h-T were significantly greater in the children with Gn (P < 0.001). No other differences for T or DHT were significant. In conclusion, the testicular response to hCG is not modified by GH. In contrast, the greater response in the presence of Gn suggests a permissive role of Gn on the testicular responsiveness to hCG.