Effects of luteinizing hormone-releasing hormone (LRH) upon bioactive and immunoreactive serum LH in patients with Turner's syndrome before and after oestrogen treatment.
One daily dose of 0.05 mg ethinyl oestradiol was administered to 5 patients with Turner's syndrome (mean age +/- SEM = 16.4 +/- 0.7 years) for 10 days. The effects of acute stimulation with luteinizing hormone-releasing hormone (LRH) (0.1 mg iv) on biologically active and immunoreactive LH were analysed before therapy and at the end of oestrogen treatment. Bioactive LH (BIO-LH) was measured by a sensitive and specific in vitro bioassay based upon testosterone production by mechanically dispersed mouse Leydig cell preparations. Immunoreactive LH (RIA-LH) was evaluated by a double antibody RIA method. Prior to oestrogen treatment, LRH induced a prompt rise in BIO-LH and RIA-LH levels, which reached peak values at 30 and 45 min, respectively. After oestrogen treatment, a delayed response (with peak values at 120 min) was observed for both BIO-LH and RIA-LH. Before oestrogen treatment, the mean bioactivity to immunoreactivity (B/I) ratio of LRH-stimulated LH showed a significant decrease from basal values (P less than 0.05). In contrast, after ethinyl oestradiol administration the mean LH B/I ratio increased significantly from basal values in response to LRH (P less than 0.05). The mean relative maximum response (delta %) for BIO-LH was significantly higher (P less than 0.05) in oestrogen-treated than in untreated patients, whereas the mean BIO-LH delta area was significantly lower in the former group (P less than 0.01). Similarly, oestrogens decreased significantly the mean RIA-LH delta area (P less than 0.05), whereas they did not affect significantly the mean RIA-LH delta %. The results further emphasize that oestrogens may change the quality of circulating LH.
D000293:Adolescent; D001681:Biological Assay; D004997:Ethinyl Estradiol / Q000627:therapeutic use*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D011863:Radioimmunoassay; D014424:Turner Syndrome / Q000097:blood* / Q000188:drug therapy
D007987:Gonadotropin-Releasing Hormone; D004997:Ethinyl Estradiol; D007986:Luteinizing Hormone