Pituitary-gonadal axis in male undermasculinisation

Aims-To study the value of assessing serum concentrations of luteinising ho rmone (LH), follicle stimulating hormone (FSH), testosterone, and dihydrote stosterone (DHT) in patients with male undermasculinisation not caused by a ndrogen insensitivity. Methods-A retrospective study of a register of cases of male undermasculini sation (20 with abnormal testes, eight with Su-reductase deficiency, three with testosterone biosynthetic defects, seven with Drash syndrome, and 210 undiagnosed). Results-A human chorionic gonadotropin (hCG) stimulation test was performed in 66 of 185 children with male undermasculinisation. In 41 of 66 patients the dose of hCG was either 1000 U or 1500 U on three consecutive days. The rise in testosterone was related to basal serum testosterone and was not s ignificantly different between the two groups. Testosterone:DHT ratio in pa tients with 5 alpha-reductase deficiency was 12.5-72.8, During early infanc y, baseline concentrations of LH and FSH were often within normal reference ranges, In patients with abnormal testes, median pre-LHRH (luteinising hor mone releasing hormone) concentrations of LH and FSH were 2 and 6.4 U/1, re spectively, and post-LHRH concentrations were 21 and 28 Un. An exaggerated response to LHRH stimulation was observed during mid-childhood in children where the diagnosis was not clear and in all children with abnormal testes. Conclusions-The testosterone:DHT ratio following hCG stimulation is more re liable than the basal testosterone:DHT ratio in identifying Sa-reductase de ficiency, During infancy, the LHRH stimulation test may be more reliable in identifying cases of male undermasculinisation due to abnormal testes than basal gonadotrophin concentrations.