Differential effect of luteinizing hormone-releasing hormone infusion on testicular steroids in normal men and patients with idiopathic oligospermia.

Basal serum gonadotropin levels in 11 oligospermic men were significantly higher than in 9 euspermic control subjects, although most were still in the normal range. Basal serum testosterone (T), 17-hydroxyprogesterone (17-OHP), and estradiol levels and their ratios did not differ significantly. Continuous luteinizing hormone-releasing hormone (LH-RH) infusion (1 microgram/minute for 180 minutes) during integrated blood sampling evoked similar gonadotropin responses in both groups but had a differential effect on T: in the control subjects T increased (P less than 0.01) within 15 minutes to 1.5 times baseline, whereas in the oligospermic men T decreased (P less than 0.01). From 60 minutes on, however, T also significantly rose in the oligospermic men, but the maximum increment was about half lower (P less than 0.01) than in the euspermic men, despite virtually similar rises in 17-OHP. Only in the oligospermic men did the 17-OHP/T ratio increase (P less than 0.02) during LH-RH, which is compatible with the occurrence of a 17,20-lyase block. Serum estradiol did not increase in either group. In conclusion, continuous LH-RH infusion uncovers an intrinsic difference in acute Leydig cell stimulation between euspermic and oligospermic men.