Galactorrhea-amenorrhea syndrome: diagnosis and therapy.

Tests of prolactin regulation in the galactorrhea-amenorrhea syndrome were compared in 18 patients with normal pituitary fossae, seven patients with prolactin-secreting adenomas, and eight normal women. Mean basal prolactin was highest in patients with adenomas and was elevated in those with normal fossae when compared with normal subjects (278 versus 73 versus 10.2 ng/ml). Levodopa, water loading, or luteinizing hormone-releasing hormone testing were of no predictive value in the diagnosis of adenoma. Some patients with adenomas show a greater prolactin response after administration of thyrotrophin hormone-releasing hormone (TRH) than of chlorpromazine, whereas these responses are usually similar in patients with normal fossae. A mean basal prolactin level above 150 ng/ml or an increase of more than 100 ng/ml after TRH administration in a patient with hyperprolactinemia unresponsive to chlorpromazine stimulation strongly suggests a prolactin-secreting tumor. However, because some patients with tumor have prolactin levels below 150 ng/ml, or do not respond to TRH stimulation, or both, functional studies alone cannot permit the diagnosis of all adenomas before the appearance of radiographic changes.