Tissue folate levels in transgenic mice with tumors and in nontransgenic controls

Tissues, whole blood, serum, and tumor folate of a tumor-bearing transgenic (TBT) mouse model for human neurofibromatosis were measured to characterize effects of neoplasia on concentration of folate among tissues and tumors. Tissues of 11 TBT mice (killed when tumor burden was estimated to be 1% of body weight to minimize possible effects of cachexia) and eight nontransgenic controls (NTC) of similar age were analyzed for folate. TBT mice had 1.5 ± 0.2 tumors. Tumor mass was 0.35 ± 0.10 g/mouse, and overall tumor folate concentrations were 0.38 ± 0.10 nmol/g. Overall total tumor folate was 0.13 ± 0.04 nmol/mouse. Body weights and erythrocyte and leukocyte counts of TBT and NTC mice were similar. Hematocrits and hemoglobin concentrations were lower in TBT than in NTC mice. Livers and kidneys from TBT mice weighed less than those of NTC mice while spleens weighed more. Both groups had similar folate concentrations in liver and spleen while concentrations in kidney, brain, and serum were lower in TBT than in NTC mice. Folate per liver, kidney, and brain was lower while that per spleen was higher in TBT than in NTC mice. Tumor folate concentrations were lower than those of most mouse nontumor tissues. Folate concentrations of tumors were variable and were ranked as follows: nose ≥ tail ≥ foot ≥ ear. The presence of tumors was associated with reduced folate concentration of some nontumor tissues. Folate concentrations of kidney, brain, and serum decreased as the number and mass of tumors increased.