Increased hepatic nicotinamide N-methyltransferase activity as a marker of cancer cachexia in mice bearing colon 26 adenocarcinoma.

When a cachexigenic subclone (clone 20) of murine colon 26 adenocarcinoma was transplanted into female BALB/c mice, hepatic NNMT activity continued to increase until death in proportion to progressive carcass weight loss, a marker of cancer cachexia. On the other hand, noncachexigenic subclone (clone 5)-transplanted mice showed neither increase of NNMT activity nor carcass weight loss. Among cytostatic fluorinated pyrimidines, 5'-dFUrd could inhibit the increase of NNMT activity and prevent weight loss in mice bearing clone 20. On the other hand, 2'-dFUrd did not show these effects. 5-FUra and Tegafur inhibited the increase of NNMT activity at higher concentrations. These findings suggest that the levels of hepatic NNMT activity are closely associated with the degree of weight loss, and they appear to be a useful marker of cancer cachexia.