Increases in serum growth hormone which characterize acute starvation in non-obese individuals were usually absent in anorexia nervosa. Serum LH was decreased with serum FSH apparently normal in the majority. Increased adrenocortical activity as indicated by high basal 11 (OH)-corticosteroids and their incomplete suppression by dexamethasone and hyperresponsiveness to exogenous ACTH was recorded in about one-half of the patients tested. Urinary steroid responses to intravenous metyrapone were normal in all but one patient who had hypothalamic-pituitary hypofunction. Thyroid function was normal but TSH shortage has been reported. Resistance to insulin and a waning of insulin responses to hyperglycemia were noted in these individuals with anorexia nervosa.