Cholecystokinin peptides in cerebrospinal fluid: a pilot study in hypothyroid patients

The cholecystokinin tetrapeptide (CCK-4) and the sulphated octapeptide (CCK -8) were measured in cerebrospinal fluid obtained from nine hypothyroid pat ients before and during L-thyroxine treatment. Before treatment, CCK-4 and CCK-8S correlated negatively with S-TSH, whereas CCK-8S also showed a posit ive correlation with S-T3. During treatment, S-T4 correlated negatively wit h CCK-8S. CSF collection time was significantly shorter during treatment th an prior to treatment for the first (0-6 mi) CSF fraction. On faking CSF co llection time into account, the levels of both CCK-4 and CCK-8S in the firs t CSF fraction were significantly increased during medication. Our results are consistent with an impact of the hypothyroid disorder and L-thyroxine t reatment on the disposition of CCK compounds in CSF. This might be due to a n altered CSF circulation, but other mechanisms (e.g. metabolism or elimina tion) cannot be ruled out. Copyright (C) 1999 John Wiley & Sons, Ltd.