Cyclic nucleotides in cerebrospinal fluid of patients with intracranial and spinal tumors

Since the cyclic nucleotides (CN) adenosine 3',5'-monophosphate (cAMP) and guanoside 3',5'-monophosphate (cGMP) are involved in the regulation of cell proliferation and tumor growth in vitro, a study was made of the levels of these compounds in the lumbar cerebrospinal fluid (CSF) of 20 patients with intracranial and spinal tumors. In the presence of benign or malignant intracranial tumors there was a slight and not significant decrease of cAMP as well as cGMP levels in the CSF, as compared to control patients. While there was no significant correlation between the levels of the two CN in controls, there was a positive correlation in tumor patients. Total protein content and cAMP were negatively correlated in malignant intracranial tumors. Possible influences of tumor growth and intracranial pressure increases on CN levels are discussed. In spinal tumor patients normal CN levels were observed. However, in a patient with meningeal sarcoma an extremely marked elevation of cAMP occurred in parallel with the extension of the tumor to the spinal meningeal space, suggesting massive secretion of cAMP from the tumor cells.