On the carbohydrate metabolism of malignant tumors.

Abstract

The free sugar, lactic acid and glycogen content of spontaneous and transplanted mouse carcinoma and of Jensen rat sarcoma has been investigated under various conditions. It was found that the free sugar content of these tumors was lower than that of any other tissue of the mouse or the rat so far investigated. Thus 16 tumors showed as an average 0.047 per cent free sugar, the maximum being 0.069 and the minimum 0.036. Comparative values for mouse organs have been obtained on a former occasion and showed as an average: liver, 0.300 per cent; muscle, 0.079 per cent; kidney, 0.126 per cent; brain, 0.059 per cent. Glucose administration had a marked effect on the free sugar concentration of the tumors. The tumors were analyzed 15, 30 and 60 minutes after giving glucose intraperitoneally. After 15 minutes the free sugar values were from 0.287 to 0.176 per cent at a blood sugar level from 0.634 to 0.396 per cent. After 30 minutes the free sugar values were from 0.311 to 0.184 per cent at a bloodsugar level from 0.464 to 0.230 per cent. After 60 minutes the free sugar values were from 0.078 to 0.057 per cent at a bloodsugar level from 0.194 to 0.166 per cent. A hyperglycemia produced by epinephrin also raised the free sugar concentration of the tumors.

The lactic acid values of 8 individual tumors ranged from 0.013 to 0.089 per cent, average 0.038 per cent. Comparative lactic acid values for other mouse tissues were: liver, 0.051 per cent for mice starved from 0 to 2 hours, and 0.011 for mice starved from 17 to 22 hours; muscle, 0.112 per cent. The lactic acid content of the tumors was considerably increased after glucose administration. Thus in 4 cases, where the tumors constituted from 2.7 to 22 per cent of the body weight of the animals, values of 0.117, 0.166, 0.160 and 0.141 per cent lactic acid were obtained; average 0.146.

The glycogen in 6 tumors varied from 0.122 to 0.303 per cent, average 0.196 per cent.