1 alpha,25-Dihydroxyvitamin D3 markedly enhances chemically-induced transformation in BALB 3T3 cells

1 alpha,25-Dihydroxyvitamin D3, a hormonally active form of vitamin D3, enhanced methylcholanthrene-induced transformation in BALB 3T3 cells to a much greater extent than 12-O-tetradecanoylphorbol-13-acetate. This enhancement was probably mediated by a cytosol receptor for 1 alpha,25-dihydroxyvitamin D3 which has an equilibrium constant of 28.4pM and a maximum binding of 32.6 fmol/mg protein.