LOSS OF WEIGHT AND LIPID SHIFTS IN ORGANS OF THE DIGESTIVE TRACT OF TUMOR-BEARING RATS IN RELATION TO TUMOR SIZE

Abstract

The objective of this project was to find to what extent loss of weight in the digestive tract might affect tumor size and age in albino rats bearing Walker carcinosarcoma 256. Wet weight, dry weight, and water content were measured upon tongue, esophagus, cardiac stomach, pyloric stomach, jejunum, ileum, cecum, colon, and residual carcass (minus tumor). The animals bore tumors weighing 12 ± 6 (mean ± S.D.) % of host (minus tumor) weight after 18 ± 6 days of tumor growth (group I), 38 ± 12% after 24 ± 6 days (group II), and 93 ± 26% after 29 ± 5 days (group III) and controls were twins of the same sex. There were few significant changes in the animals of group I. In group II, there was loss of dry weight in all organs except pyloric stomach, losses being percentagewise the same as in residual carcass. Loss of dry weight of jejunum and ileum was less in rats of group III than in those of group II. In group III, loss of weight in other organs tended to be less than in residual carcass. Loss of dry weight in residual carcass was not significantly greater in the animals of group III than in those of group II. Water levels were increased in all organs of rats in groups II and III. This evidence indicates that rats of group III may have lived longer after tumor implantation, lost no more carcass weight, and bore larger tumors because they had lost weight in the small bowel at a lesser rate than had the rats of group II.Further studies revealed that lipid shifts were in general less marked in organs which had lost the least weight. In animals bearing large tumors, percentage loss of neutral fat was less in most organs of the digestive tract than in the residual carcass. Increases in the levels of cholesterol and phospholipid were less in pyloric stomach and small bowel than in other organs of the digestive tract. Shifts in the amount of nonlipid dry weight and in levels of lipids and water were in general less in pyloric stomach and small bowel than in other organs of the body. In these respects, pyloric stomach and small bowel resembled brain, heart, and lung. It is suggested that resistance of pyloric stomach and small bowel to the cachectic influence of the tumor may be a factor determining tumor size and length of survival of the host.