Dissociation between CSF and plasma B-endorphin in major depressive disorders: evidence for a different regulation

Plasma and cerebrospinal fluid (CSF) levels of ACTH, B-lipotropin (B-LPH) and B-endorphin (B-EP) were simultaneously measured in 10 patients with major depression (35-57 yr) with a disease history of 10-34 yr, 7 of them with recurrent episodes, and in 13 age-matched healthy controls. In patients, lumbar puncture was performed after a 10 days drug-free period. Plasma B-EP and B-LPH levels were measured by RIA after silicic acid plasma extraction and Sephadex G-75 column chromatography. Plasma ACTH concentrations were measured by IRMA. For CSF assays the extraction step was avoided. In depressed patients, plasma ACTH (16.2 +/- 6.9 fmol/ml, mean +/- SD), B-LPH (19.8 +/- 8.5) and B-EP (17.8 +/- 7.0) levels were significantly higher (p less than 0.01) than in controls. On the contrary, CSF levels of the three peptides were similar in the two groups. No correlations were found between plasma or CSF concentrations and duration of the disease or severity of the actual episode. These data add further evidence to the independent regulation between central and peripheral POMC-related peptides. They also reduce the possibility that peptides of pituitary origin, directly from the gland or through the peripheral circulation, could penetrate the CSF.