Increase of β-endorphin in cerebrospinal fluid after removal of ACTH-secreting pituitary adenomas

Abstract
.beta.-Endorphin and met-enkephalin in CSF were measured before and after removal of an ACTH-secreting adenoma in Cushing''s disease by a sensitive radioimmunoassay and a radio-receptor assay, respectively. After tumor resection the level of ACTH in plasma markedly decreased from 82.6 .+-. 22.7 pg/ml to 16.7 .+-. 4.1 pg/ml (mean .+-. SE, n = 4). The level of .beta.-endorphin in CSF significantly increased from 32.0 .+-. 4.5 pg/ml to 61.8 .+-. 10.7 pg/ml (P < 0.05) after tumor resection while the level of metenkephalin in CSF remained unaltered. Hypophysectomy may induce an increase of .beta.-endorphin in CSF.