Selective bilateral blood sampling from the inferior petrosal sinus in Cushing's disease: effects of corticotropin-releasing factor and thyrotropin-releasing hormone on pituitary secretion.

We sought to enhance the sensitivity of selective bilateral blood sampling to determine adrenocorticotropin (ACTH) and prolactin levels in the inferior petrosal sinus (IPS) by administering two stimulatory agents--corticotropin-releasing factor (CRF) and thyrotropin-releasing hormone (TRH). We then determined the ACTH and prolactin levels in the IPS of 10 patients with Cushing's disease. After peripheral administration of both CRF and TRH, ACTH levels were significantly higher on the tumor side in all patients. The prolactin level was significantly higher on the tumor side when CRF or TRH was used to stimulate pituitary secretion. Postsurgical immunohistochemistry studies revealed productio…