Serum concentrations of gonadotrophins in hypergonadotrophic patients following stimulation by a long-acting analogue of luteinizing hormone-releasing hormone.

The effect of D-Ser(TBU)6-EA10-LRH, a long-acting analogue of luteinizing hormone-releasing hormone (LRH), was studied in patients with hypergonadotrophism due to orchidectomy (n = 8) or due to Klinefelter's syndrome (n = 6). Patients orchidectomized less than 7 days prior to the administration of the compound presented with maximum concentrations of LH (63.8 +/- 29.9 mIU/ml) within 60 min following iv injection of the LRH-analogue (10 micrograms). This behaviour of LH was qualitatively similar to that seen in healthy men. In patients orchidectomized more than 40 days prior to the administration of the LRH-analogue and in patients with Klinefelter's syndrome the occurrence of maximum serum LH-concentrations (115.0 +/- 39.4 and 149.4 +/- 134.5 mIU/ml, respectively) was delayed up to 240-360 min following iv LRH-analogue. This pattern of LH secretion is similar to that of healthy women. No qualitative differences in stimulated FSH-concentrations were observed between the described groups of hypergonadotrophic patients. These findings demonstrate a time-dependent increase in the 'second pool' of LH following orchidectomy. The similar behaviour of stimulated LH-release in healthy women and in male patients with long-term hypergonadotrophic hypogonadism could indicate an augmented production of endogenous LRH in these individuals as compared to healthy men, providing an explanation for the sexually related differences in the LH-response upon the administration of the LRH-analogue.