The activities of NAD- and FAD-linked a-glycerophosphate dehydrogenase(a-G3PDH) (sn-glycerol-3 phosphate: NAD+ 2-oxido:-eductase, EC 1. 1. 1.8) were observed in serum, liver, kidney and spleen of the mouse transplanted with Sarcoma 180 ascites tumor in peritoneal cavity. The enzymes were prepared from tissues of the mouse every 3 day after transplantation and their activities were determined by the methods of White & Kaplan and Dawson & Thorne. Isoelectric point of NAD-linked a-G3PDH was determined through the poIyacrylamide gel electrofocusing electrophoresis by the method of Winter et al.
The experimental results were summarized as follows;
1. The activity of FAD-linked a-G3PDH in tumor cell was 105.5 units per gram of cells but that of NAD-linked a-G3PDH was not detected. However, the activity of NAD-linked a-G3PDH was 325.3 units per ml in ascitic fluid, while the activity of FAD-linked a-G3PDH was as low as 0.4 unit per ml.
2. Specific activities of NAD-linked and FAD-linked a-G3PDH in liver of normal mouse were 137.0: 9. 87 and 1. 60. 16, but these activities were remarkably increased to 273. 8-8. 57 and 2. 7--0. 26 at 3 weeks after transplantation, respectively.
3. Specific activities of these enzymes in kidney from mouse at 3 weeks after transplantation were increased as compared with normal mous(NAD-linked: normal, 118.3-4-6.63; 21th day 1917.5-4-9.95; FAD-linked: normal; 0.30.07, 21th day 1. 3+0. 18).
4. Specific activity of NAD-linked a-G´ PDH in spleen from the mouse at 3 weeks after transplantation was slightly increased as compared with that of normal mouse (normal, 6. 9-1. 11; 21th day 3. 4_0. 7), but that of FAD-linked a-G3PDH was remarkably decreased (normal, 1. 1-0. 16; 21th day 0 1_0.`11).
5. Specific acitivity of NAD-linked a-G3PDH in serum of normal mouse was 0. 8-0. 05 and, that of transplanted mouse at the 6th day was 2.3-0. 1. Thereafter, the specific activity of the enzyme was gradually decreased. But the activity of FAD-linked a-G3PDH was not detected in serum.
6. NAD-linked a-G3PDH in serum of normal mouse was composed of 2 isozymes that have different isoelectric point(pI 6.9 and 6.6). Three weeks after transplantation of tumor cell; another isozyme occured at more acidic range (pI 6. 4) and the relative activity of this one was increased according to time course.
In conclution, these results suggest that evaluation of changes in isozyme patterns and enzyme activity in serum would be used as a monitor for diagnosis of ascites tumor.
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