DIMETHYL-SULFOXIDE ALTERS MITOGEN-INDUCED PRODUCTION OF DIACYLGLYCEROL AND GTP-BINDING TO PLASMA-MEMBRANES IN MOUSE EMBRYO FIBROBLASTS

Dimethyl sulphoxide (DMSO) is, polar solvent often used as an inducer of erythroid differentiation. In order to elucidate the mode of action of DMSO, we studied its effects on two early events in signal transdu ction, namely diacylglycerol (DAG) production and guanosine triphospha te (GTP) binding. Mouse embryo fibroblasts showed a bimodal profile of diacylglycerol synthesis in the presence of DMSO. platelet derived gr owth factor (PDGF) mediated synthesis of diacylglycerol synthesis was inhibited by DMSO. Also DMSO down regulated serum induced GTP-binding to isolated plasma membranes of mouse embryo fibroblasts. However, the control and the ras (T24) oncogene transformed Rat-2 cells did not sh ow any increase in GTP-binding on serum stimulation while showing a ma rginal decrease in GTP-binding in the presence of DMSO. DMSO may hence act by inhibiting the perpetuation of mitogenic signal transduction a t an early stage.