Formation of acetylpolyamines and putrescine from spermidine by normal and transformed chick embryo fibroblasts

Polyamine uptake and metabolism were studied in cultures of normal and Rous sarcoma virus–transformed chick embryo fibroblasts. The uptake of radioactive putrescine and spermidine by the transformed cells was faster than that of the normal controls. The amount of radioactive putrescine and polyamines taken up by the transformed cells also exceeded that observed with normal fibroblasts. The intracellular levels of putrescine, spermidine, and spermine were considerably higher in the transformed cells than in the normal controls. Radioactive spermidine was converted into N–acetylputrescine and N¹–ace–tylspermidine by the transformed cells. The extent of this conversion by the normal fibroblasts was significantly lower. Radioactive putrescine and spermine were also formed from radioactive spermidine added to cultures of transformed fibroblasts. The rate of this conversion was significantly slower in normal chick embryo fibroblasts.