Table 2.

Effect of CrCl₃, Na₂Cr₂O₇, NaCl, ZnCl₂ and NaNO₃ on intact HeLa cell DNA synthesis

Time Conc. (μM)	1 h			2.5 h			8 h
	1	10	100	1	10	100	1	10	100
Na2Cr2O7	100±4.9	88.7±3.9	73.3±2.2	91.3±3.1	74±4.6	9.1±3.9	91.2±6.0	54.5±2.8	5.6±2.5
CrCl3	100±3.1	96.2±5.4	90.8±3.1	111±1.6	111.7±1.4	98.0±2.6	106±7.0	107±2.4	105±2.6
NaCl	105±4.1	93.8±2.2	99.2±4.7	93.8±6.0	95.8±4.0	95.3±4.3	96.1±6.4	102±5.1	93.7±6.9
ZnCl2	98.6±5.2	99.6±6.2	91.0±2.9	99.6±6.2	90.3±3.2	93.4±2.1	101±5.2	91.0±5.6	98.0±4.3
NaNO3	103±4.9	99.2±3.5	92.6±5.5	91.4±3.9	89.1±2.9	91.2±3.6	97.8±4.5	98.1±3.4	97.7±3.9

HeLa cells were grown in culture and incubated with a range of concentrations of these salts, as described in the Methods. Intact cell DNA synthesis was determined by measuring the incorporation of ³H-thymidine into acid insoluble and retention on GF/A filters as described in the Methods. The mean values±S.E are reported in the table, and represent the average of 3 independent experiments, and are expressed as a percentage of radiolabel incorporated into acid insoluble material from cultures grown in the absence of these metal salts. (% of control, Mean).