Estimation of poly (C) avid serum ribonuclease in hepatoma patients

Human poly (C) avid serum ribonuclease (RNase) differs in physico-chemical, electrophoretic, and catalytic properties from ribonuclease activity encountered in liver preparations. The first is reported as "secretory type", the latter, because it is undetectable in body fluids, as "nonsecretory type". We determined RNase activity in 11 hepatoma patients. A statistical difference from a normal control of corresponding age was encountered in both age groups investigated (51-60 years, P less than 0.05; 61-70 years, P less than 0.01). The circumstances mentioned above make the tumor itself unlikely to be the source of RNase elevation. Besides a diminished synthesis of RNase inhibitor by hepatoma cells, tumor-derived polyamines could contribute to enhanced RNase activity. The influence of polyamines on RNase activity has already been demonstrated by in vitro experiments. Simultaneous estimation of polyamines and RNase is required to elucidate in vivo circumstances.