SERUM LUTEINIZING-HORMONE PULSATILITY AND INTRATESTICULAR TESTOSTERONE AND ESTRADIOL CONCENTRATIONS IN IDIOPATHIC INFERTILE MEN WITH HIGH AND NORMAL FOLLICLE-STIMULATING-HORMONE SERUM CONCENTRATIONS

The purpose of the study was to evaluate pulsatile luteinizing hormone (LH) release and intratesticular concentrations of testosterone and oestradiol in infertile men, to determine if alterations in gonadotrophin secretion are associated with changes in the testicular concentrations of steroids. Patients with idiopathic oligo/azoospermia were divided into a high follicle stimulating hormone (FSH) group (n = 5) and a normal FSH group (n = 6). Blood samples were taken every 15 min for 6 h to determine LH, FSH, testosterone, oestradiol, sex hormone binding globulin, bioactive LH and bioavailable testosterone. The patients underwent a bilateral testicular biopsy for histological assessment and to determine testosterone and oestradiol concentrations. Serum measurements were compared with those of seven fertile men. The high FSH group had a higher concentration of serum LH and oestradiol than normal men (P < 0.01) and showed a lower frequency of LH pulses than the normal FSH group and control men (P < 0.01). Intratesticular oestradiol was higher in the high FSH group (P < 0.001), with a lower testosterone/oestradiol ratio (P < 0.01). Patients showed a negative correlation between the serum testosterone/LH ratio and FSH (r = -0.75; P < 0.01) and a positive correlation between the testicular oestradiol concentration and serum FSH (r = 0.86; P < 0.01). The histopathological examination only showed a smaller tube diameter in the high FSH group (P < 0.05). These data seem to indicate that a higher intratesticular concentration of oestradiol with a lower testosterone/oestradiol ratio in the high FSH group could have a deleterious effect on spermatogenesis.