Receptor for 1,25-dihydroxyvitamin D3 in GH3 pituitary cells

Cytosol prepared in 0.3 M KCl from pituitary GH3 cells, but not from AtT-20 cells contains a receptor-like macromolecule that binds 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) with specificity and high affinity (Kd = 2.9 x 10(-10) M). The GH3 cytosolic binding component sediments at 3.3 S in high-salt sucrose gradients and adsorbs to DNA-cellulose; its elution profile from DNA-cellulose and other biochemical properties are indistinguishable from those of classical 1,25(OH)2D3 hormone receptors. The presence of the 1,25(OH)2D3 receptor in pituitary cells which secrete primarily growth hormone and prolactin (GH3), but not in a line which secretes the 31,000-dalton ACTH precursor and its derived peptides (AtT-20), suggests that 1,25(OH)2D3 may play a regulatory role in specific pituitary cells.