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The influence of the epidermal growth factor (EGF, 5 ng/ml) and(or) insulin (1 microgram/ml) on the number of transforming growth factor beta (TGF-beta) specific binding sites in cells with different proliferative response on the TGF-beta action and on the affinity (Kd) of these sites to the ligand was studied. The total amount of TGF-beta binding sites (49,300 +/- 3000) in the cells of NRK-49F line, which are stimulated to proliferation by TGF-beta in the presence of EGF and insulin, decreased under the influence of the mixture of the latter factors (31,300 +/- 4000). In the presence of EGF, this amount did not change (40,900 +/- 6000), while in the presence of insulin it increased (81,200 +/- 9000). Kd of TGF-beta receptors (27.3 +/- 3.0 pM) in the above mentioned variants of experiments did not change. When the cells of A-549 line from human lung adenocarcinoma were investigated (the proliferation of these cells is inhibited by TGF-beta), it was shown that EGF induced the elevation of the amount of TGF-beta binding sites from 9700 +/- 700 to 21,600 +/- 900. Insulin or its mixture with EGF did not change that amount. EGF and(or) insulin did not influence the Kd (27.0 +/- 6.0 pM) of TGF-receptors in these cells. The obtained data are compared with the results of the influence of TGF-beta and of its combinations with EGF, and (or) insulin on the intensity of DNA synthesis and on proliferation in both the investigated cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)