The glucose analogue, 2-deoxy-n-glucose, has been found to inhibit glycolysis and the growth of yeast (1, 2) and various animal tissues (3-7). It is phosphorylated by hexokinase (8), but is not believed to be further metabolized. Wick et al.(9) have reported that deoxyglucose B-phosphate competitively inhibits the conversion of glucose 6-phosphate to fructose 6-phosphate by a purified phosphohexose isomerase from kidney. Recently Kipnis and Cori (10) have presented evidence that deoxyglucose 6-phosphate noncompetitively blocks the transport of glucose. It has also been suggested that the phosphate inhibits glycolysis at the hexokinase level (9). The experiments described in this paper show that deoxyglucose inhibits the growth of human cell cultures by inhibiting the utilization of glucose. They also indicate the sites of inhibition of glucose utilization in the glycolytic and oxidative pathways. The implications of these findings on the possible mode of action of deoxyglucose are discussed.

EXPERIMENTAL PROCEDURE Two human cell lines were used in the present studies, the HeLa, derived from a human carcinoma, and a culture of intestine from normal embryonic human tissue. The cells were grown both in monolayers, adherent to glass, and in suspension. The composition of the medium for the stationary cultures has been described previously (11) as have methods for cultivation and assay of growth (12). The growth in suspension was carried out as described by McLimans et al.(13), with the use of Eagle’s basal medium (18) supplemented with 5% dialyzed human serum.