Evaluation of hypothalamic-pituitary function in patients with thalassemia major

The increased survival of patients with thalassemia major, made possible by more adequate therapeutic regimens, has emphasized the importance of the endocrine abnormalities often associated with this disease. In twelve thalassemic patients, we evaluated the hypothalamic-pituitary function by measuring plasma levels of anterior pituitary hormones under basal conditions and in the course of provocative tests. An impairment of growth hormone (GH) secretion was demonstrated in a considerable proportion (7/12) of these patients. In some of them failure of GH response to insulin-hypoglycemia and normal hormone rise after growth hormone-releasing hormone indicate a hypothalamic defect. A defective prolactin secretion was observed in the female hypogonadic but not in the male thalassemic patients. This abnormality appears to be dependent on estrogen deficiency rather than on a hypothalamic-pituitary dysfunction. In our series a high prevalence (8/12) of hypogonadism was also noticed. In these cases, the low gonadotropin levels and their unresponsiveness to gonadotropin-releasing hormone are compatible with a hypothalamic and/or pituitary damage. Lastly, the enhanced ACTH responses to the stimuli associated to a reduced cortisol release suggest the existence, in these patients, of a diminished adrenocortical reserve. On the whole, this study has shown several derangements of the hypothalamic-pituitary function in thalassemia. This emphasizes the need for careful endocrine surveillance in this disease.