In vitro incorporation of C14-DL-leucine into normal and leukemic white cells.

By W. H. BAKER, P. C. ZAMECNIK AND M. L. STEPHENSON I N 191 1, Grafe demonstrated that hunsams leukemssic heukocytes possessed an oxidative metabolisns.’ Since that time, many comparative studies on tiormal amid leukemic humisan leukocytes have revealed major quantitative differetsces in their biochemical amid emizynsatic comsstituemits. 5 Details of these differences may be foumid iii the re(’emst reviews of this subject by Valemstitse.67 Previous experitrients dotse in this laboratory showed that the iii vitro incorporation of C’4-leucitse om’ C’4-alamiitie into the ivhite i)lood cell proteins was of the order of six times greater in cells frons patiemsts with acute leukemia, as compared with miormal white cells. White cells in chronic leukensia, both myelogenous and lynsphatic, showed incorporatioms rates which were only slightly higher thams normal cells.8 More recemstly, Weisberger et al. studied the uptake of S35-Lcystimie and S35-L-methiotiitse by tiormal amid leukemic cells iii vivo and by leukemic cells iii vitro.9t0 Its vivo studies revealed that leukemic cehls had a higher uptake of these two amino acids thati did the normal white blood cells, amid led to the use of selenium cystitie its therapeutic trial for acute leukemia.” Sitice the in vitro techmsie nseasures au active metabolic process, the object of the presemit study was to utilize this mssethod to follow the in vitro survival time of both normal amid leukensic white cells.