Hypothalamic function in patients with tumors of the pineal area

10 patients, aged 4-17 years, were investigated in order to study the influence of tumors of the pineal area on the hypothalamic endocrine function. Immunoreactive growth hormone (GH) failed to increase sufficiently in 9 patients after insulin induced hypoglycemia (IIH) and in seven patients after propranolol-glucagon (PG). Secondary adrenocortical insufficiency was present in four patients. Three of these patients showed biochemically hypothalamic hypothyroidism with elevated basal prolactin levels, hypogonadotropic hypogonadism and neurohumoral diabetes insipidus. The study shows that hypothalamic dysfunction in patients with tumors of the pineal area is at least as frequent as in patients with suprasellar tumors and that diabetes insipidus may be present before any surgical or radiological treatment.