Figure 1.

(A) T84, Caco2, or SW480 cells, stimulated with 10% FBS, were incubated for 48 h with 1 μM ST (■) or PBS (□), and then protein and/or cells were quantified as described in Materials and Methods. Values are expressed as the percentage increase in cell number or protein stimulated by FBS relative to those values at t₀ (baseline). Total cells at t₀ were: T84, 4.7 × 10⁶ ± 0.2; Caco2, 1.8 × 10⁶ ± 0.4; and SW480, 3.3 × 10⁶ ± 0.4. T84 protein content at t₀ was 0.5 ± 0.02 mg/ml. (B) T84, Caco2, and SW480 cells were synchronized 6 h after seeding by starvation for 18 h and then stimulated with 10% FBS for 24 h in the presence of 1 μM ST (■) or PBS (□). After 21 h, [³H]thymidine was added to the media, and incubation was continued for another 3 h. [³H]Thymidine incorporation into DNA was quantified as described in Materials and Methods. Values are expressed as a percentage of the [³H]thymidine incorporation stimulated by FBS in the presence of PBS. (C) T84 cells were synchronized by starvation, stimulated to proliferate by addition of 10% FBS, and exposed to [³H]thymidine and the indicated concentrations of ST, as described in B. After 24 h of incubation, [³H]thymidine incorporation into DNA was quantified as described in Materials and Methods. *, P < 0.05; **, P < 0.01.