Luteinizing hormone pulsatility in men with damage to the germinal epithelium

Bioactive-LH (B-LH) was measured in plasma by in-vitro bioassay and immunoactive-LH (I-LH) by immunoassay at 10 min intervals for 6 h in five men after standard chemotherapy for Hodgkin's disease. Eleven normal men acted as controls. Follicle-stimulating hormone (FSH) was markedly raised in the treated patients (mean +/- SEM; 12.8 +/- 2.8 vs. 2.7 +/- 0.4 IU l-1, P less than 0.006) reflecting damage to the germinal epithelium. Bioactive (27.4 +/- 2.8 vs. 12.9 +/- 1.3 IU l-1) and I-LH (9.6 +/- 2.0 vs. 4.9 +/- 0.4 IU l-1) were elevated (P less than 0.006) in the patient group whilst testosterone levels (24.0 +/- 3.8 vs. 19.6 +/- 2.4 nmol l-1) were normal. The testosterone I-LH ratio, a putative index of Leydig cell dysfunction, was negatively correlated with FSH levels (r = -0.85, P less than 0.02). Bioactive and I-LH pulse peak amplitude were elevated, as were pulse maxima (P less than 0.05). In contrast, B-LH pulse frequency was similar between the patients (2 pulses per 6 h) and controls (median 2, range 1-3 pulses per 6 h) as was the I-LH pulse frequency (median 2, 1-2 pulses per 6 h in both groups). The mean B:I LH ratios were similar (2.94 +/- 0.09 vs. 2.63 +/- 0.14) in both groups, although the inter-pulse B:I ratio was increased (P less than 0.007) in the patient group.(ABSTRACT TRUNCATED AT 250 WORDS)