THE HYPOTHALAMUS-PITUITARY-GONAD AXIS AND TESTICULAR FUNCTION IN MALE-PATIENTS AFTER TREATMENT FOR HEMATOLOGICAL MALIGNANCIES

Objective. The effect of aggressive chemotherapy on the hypothalamus-p ituitary-gonad axis and on testicular function was assessed in nine ma le patients who had received chemotherapy only (CT, group I) and in 10 males after allogeneic bone marrow transplantation (BMT, group II). T he mean time from CT or BMT to the assessment was 3.7 (range, 1.0-11.7 ) years. Design. The responses of follicle-stimulating hormone (FSH) a nd luteinizing hormone (LH) were assessed by the gonadotropin-releasin g hormone (GnRH) test and, in addition, serum basal values for testost erone and sex hormone binding globulin (SHBG) were measured and the fr ee androgen finder (FAI) was calculated. In 13/19 patients the human c horionic gonadotropin (hCG) test was performed. Results. In group I, o nly one patient had an abnormal basal FSH value, but all (100%) had pa thologically poor responses to the GnRH test. In contrast, all baselin e FSH values were raised in group I:I (mean, 18; range, 11-30 U L-1), indicating toxic injury to the seminiferous tubules. Also in group II the responses to GnRH were low throughout the test (90%) and there wer e no clear peak values. In group II, the basal FSH and its maximum res ponse to GnRH were significantly more affected than in group I (P < 0. 001). The difference may be due to the effect of the conditioning regi men. Serum basal LH was raised in three of the patients in group I and they also had abnormal releasing test responses. In group II, baselin e LH was abnormal in four patients, but the responses to GnRH were nor mal. However, the maximum response to the releasing test: was signific antly more affected in group II (P = 0.024). Serum testosterone levels were normal in all test subjects in both study groups. However, in tw o patients in both groups, the serum free androgen index was below the low reference limit. and an impaired response of serum testosterone t o hCG stimulation was common (60%). Conclusions. A toxic injury in the testis is common in haematological patients, especially after high-do se chemoradiotherapy. Serum basal testosterone usually remains normal, but even then subnormal serum free androgen index, impaired testoster one response to hCG injection and abnormal response in LH may indicate a deficient androgen status. It may well be that testosterone replace ment therapy should be considered in these cases.