Since medial temporal lobe structures are involved in the modulation of endocrine function and temporal lobe epileptics commonly show personality changes that resemble endocrine disorders, the existence of neuroendocrine dysfunction in temporal lobe epileptics was investigated by comparing the response of serum luteinizing hormone levels with intravenous luteinizing hormone-releasing hormone infusion in patients and normal controls. Five of seven consecutive patients had response curves that fell almost entirely outside of the normal control range, and all seven had either baseline or peak values that were outside of the normal range. These findings suggest that hypothalamic-pituitary control of gonadotropin secretion may be altered among patients with temporal lobe epilepsy.