Ehrlich ascites tumour cells have a more active mitochondrial polyamine transporter than that of rat liver

Abstract

In this study we compare the uptake of spermine by mitochondria from Ehrlich ascites tumour cells with those from rat liver. The spermine uptake 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 Vmax was more than 6 times higher in tumour mitochondria. As in liver mitochondria, the uptake of spermine by ascites mitochondria was competitively inhibited by the polyamine spermidine and by putrescine. Mg2 was also inhibitory, as were the monovalent cations K+, Na+, Li+ and choline.