Increased urinary excretion of cyclic guanosine monophosphate in rats bearing Morris hepatoma 3924A.

Urinary excretion of cyclic guanosine monophosphate (GMP) increased in rats bearing Morris hepatoma 3924A, and a correlation coefficient of .842 was observed comparing nucleotide excretion and tumor size. Irradiation of tumor or 5-fluorouracil administration delayed the increases in urinary cyclic GMP and tumor size. Surgical removal of tumors resulted in a rapid decline in cyclic GMP excretion to baseline levels. Cyclic adenosine monophosphate excretion was not altered by implantation, irradiation, or excision of tumor.