Pseudocyesis was clinically established in a 39-year-old woman. Pituitary function was assessed with the use of hypothalamic peptides and dopamine receptor agonists. Basal serum concentrations of anterior pituitary and ovarian hormones were normal. An exaggerated rise in luteinizing hormone (LH) and prolactin levels was seen following the administration of luteinizing hormone-release hormone and thyrotropin-releasing hormone (TRH), respectively. A paradoxic rise in growth hormone (GH) levels followed TRH administration, whereas the response to dopamine receptor agonists was normal. Pituitary hormone secretion after deflation remained similar to that before deflation, although a normal response of GH to apomorphine was reestablished. These data indicate that the amenorrhea of pseudocyesis is associated with normoprolactinemia and a readily releasable pituitary LH pool, which suggests a suprahypophyseal etiology of the amenorrhea. The abnormalities in GH secretion may also support this contention.