Increase in the gastrointestinal absorption and in tissue storage of cyclophosphamide in L-1210 leukaemic mice at an advanced stage of the disease.

BDF1 mice were inoculated with 10(6) leukaemic cells and, together with control mice, were given a single oral dose of cyclophosphamide-14C of 100 mg/kg body weight. In the leukaemic mice we observed an increased 14C concentration in the plasma, bone marrow, liver, lungs, spleen, kidney and particularly fat where the level was 2-4 times higher than in control mice. Conversely, during the same period, significantly less 14C was detected in the stomach and small intestine of the leukaemic mice. These results were obtained 6 days after tumour transplantation (median survival time 7.7 days) whereas no differences were observed when the studies were carried out 4 days after tumour transplantation. These findings indicate an increase in the gastrointestinal absorption and in the tissue storage fo cyclophosphamide in L-1210 leukaemic mice at an advanced stage of the disease.