Gonadotropin insufficiency in patients with thalassemia major.

To elucidate whether the cause of sexual maturational arrest in thalassemia major is of hypothalamic or pituitary etiology, three female and two male patients were extensively studied. After the iv administration of 150 micrograms gonadotropin-releasing hormone (GnRH) and 500 micrograms of TRH, all patients demonstrated a minimal LH and no FSH response, with variable PRL and TSH responses. The test was repeated after the patients received 100 micrograms GnRH im daily for 7 days. The LH, FSH, PRL, and TSH responses were similar to those obtained previously. The female patients were then retested twice, after priming with 17 beta-estradiol (2 mg daily for 7 days) and again after treatment with human menopausal gonadotropins. The male patients were treated with hCG and, after testosterone reached normal adult male values, the GnRH-TRH stimulation test was repeated. In both the female and male patients, the pituitary responses remained unchanged. These results demonstrate the presence of primary gonadotropin insufficiency as well as the lack of positive estrogen feedback mechanism in patients with thalassemia major. The site of this abnormality has been demonstrated to be the pituitary gland, since hemosiderosis of the pituitary without hypothalamic involvement has been found at autopsy in one patient.