Diacylglycerol inhibits gap junctional communication in cultured epidermal cells: evidence for a role of protein kinase C.

Incubation of mouse epidermal HEL-37 cells with 1-oleoyl-2-acetylglycerol (OAG) caused a dose-dependent and transient inhibition of the transfer of microinjected fluorescein between contacting cells. Soluble extracts of HEL-37 cells contained protein kinase C activity after fractionation on DEAE-cellulose and translocation of this activity to the particulate fraction occurred after 10 min exposure to OAG or to 12-O-tetradecanoylphorbol-13- acetate (TPA). After 18 h exposure to TPA essentially all the protein kinase C activity was lost. In such TPA treated cells the transfer of microinjected fluorescein was refractory to inhibition by both TPA and OAG.