Effects of Synthetic Luteinizing Hormone-Releasing Hormone on Plasma Levels of Luteinizing Hormone and Follicle-Stimulating Hormone in Man

Abstract

Effects of synthetic LH-RH were studied in 5 normal males, 5 normal females and 13 patients with various endocrine or metabolic disorders by measuring plasma LH and FSH levels. In some normal subjects plasma GH and TSH were determined simultaneously with plasma LH and FSH. The administration of 100μg synthetic LH-RH intramuscularly to normal males and females caused a prompt and marked increase in plasma LH levels. The maximum response was observed at the 30 min after the injection and the degree of increments was 6-25 fold in male and 3-6 fold in female. Plasma FSH levels were also increased in 3 male cases and in all female cases, but the degree of responses was smaller as compared with that of plasma LH. A postmenopausal woman with high initial plasma LH and FSH values was responded markedly to synthetic LHRH and the response lasted longer. Synthetic LH-RH had no effects on plasma GH and TSH levels. Patients with pituitary insufficiency failed to show any significant increase in plasma LH and FSH levels in response to synthetic LH-RH. Patients with the other endocrine disorders showed a normal response to synthetic LH-RH as well as 2 cases of anorexia nervosa with amenorrhea. These data indicate that synthetic LH-RH is an useful material to investigate the pituitary gonadotropin reserve in man and that LH-RH has an intrinsic FSH-RH activity, even though it is weaker than LH-RH activity. In addition, the usefulness of this material when employed with the conventional pituitary function tests was discussed.