Figure 2.

(A) TGFβ sensitivity measured by [³H]-thymidine incorporation in parental and transformed RIE-1 cells. Subconfluent, rapidly growing cells were treated with 10 ng/ml TGFβ1 for 18 hours. Thymidine incorporation was measured as described in Materials and Methods. Results are expressed as a percentage of thymidine uptake in cells treated with vehicle alone. Individual data points are the mean of quadruplicate determinations. Similar results were obtained in three additional experiments. (B) TGFβ sensitivity measured by cell counting. Subconfluent, rapidly growing cells were treated with 10 ng/ml TGFβ for 48 hours. Cells were trypsinized and counted using a hemacytometer. Results are expressed as a percentage of cell numbers in cells treated with vehicle alone. Individual data points are the mean of quadruplicate determinations. Similar results were obtained in three additional experiments.