EHRLICH ASCITES TUMOR-CELLS HAVE A MORE ACTIVE MITOCHONDRIAL POLYAMINE TRANSPORTER THAN THAT OF RAT-LIVER

In this study we compare the uptake of spermine by mitochondria from E hrlich ascites tumour cells with those from rat liver. The spermine up take was membrane potential-dependent in both systems, but there were significant quantitative differences. The amount of spermine taken up by tumour mitochondria as a function of time was twice as large and a Lineweaver-Burk analysis showed that the V-max was more than 6 times h igher in tumour mitochondria. As in liver mitochondria, the uptake of spermine by ascites mitochondria was competitively inhibited by the po lyamine spermidine and by putrescine. Mg-2 was also inhibitory, as wer e the monovalent cations K+, Na+, Li+ and choline.