VITAMIN-D INFLUENCES GAP JUNCTIONAL COMMUNICATION IN C3H 10T 1/2 MURINE FIBROBLAST CELLS/

Vitamin D3, cholecalciferol, induces cell-cell communication via gap j unctions in murine fibroblasts (C3H/1OT 1/2 cells) at concentrations b etween 0.01 and 1.0 mu M, as assayed by the dye transfer method using Lucifer yellow CH. The extent of induction is similar to that obtained with the positive controls, canthaxanthin or retinoic acid, applied a t 10 and 1 mu M, respectively. Vitamin D2 also induces cell-cell commu nication. At elevated concentrations of vitamin D3 (5 mu M) there is a suppression of gap junctional communication, reversible upon exposure to all-trans retinoic acid (1 mu M) after removal of vitamin D3 from the medium. Conversely, communication between cells prestimulated with retinoic acid (1 mu M) rapidly decreases when the retinoid is replace d by vitamin D3 (5 mu M). The data demonstrate a role for vitamin D in the regulation of intercellular communication. This novel property of vitamin D may contribute to the antiproliferative effects of vitamin D exhibited in some types of cancer.