CHOLECYSTOKININ PEPTIDES IN CEREBROSPINAL-FLUID - A STUDY IN HEALTHY MALE-SUBJECTS

The clinical reliability of measuring cholecystokinin (CCK) peptides i n the cerebrospinal fluid (CSF) has not been fully elucidated. Therefo re, we have assayed CCK-8S and CCK-4 in CSF obtained from 14 healthy m ale subjects, lumbar-punctured at the L4-5 level following a strictly standardised procedure. CSF concentrations of free CCK-8S and free CCK -4 were used as dependent variables while age, height, body weight, at mospheric pressure and some other factors served as independent variab les. It was shown that the CCK-8S ratio between the second (7-12 ml) a nd first (0-6 ml) CSF fractions, correlated significantly with the atm ospheric pressure at the time of puncture. Neither CCK-8S nor CCK-4 di splayed concentration gradients in CSF. The CCK-4 levels, expressed as pmol l(-1) in the total amount of CSF were found to be positively cor related with the neuraxis distance in the lying position and negativel y with the neuraxis distance in the sitting position. Furthermore, CCK -4, expressed as pmol l(-1) per min of tapping-time (pmol l(-1) min(-1 )), showed a negative correlation with storage time, presumably mirror ing a proteolytic process. CCK-8S and CCK-4 intercorrelated positively independently of whether expressed as pmol l(-1) or pmol l(-1) min(-1 ). In conclusion, the results of this exploratory study indicate that the neuraxis distance (in the sitting and lying positions) and storage -time have to be accounted for when interpreting data on CSF levels of CCK-4. Attention has to be paid to the potential influence of atmosph eric pressure on the concentration ratio of CCK-8S. (C) 1997 Elsevier Science B.V.