INHIBITORY EFFECTS OF 12-O-TETRADECONYLPHORBOL-13-ACETATE ON DYE LEAKAGE FROM SINGLE NOVIKOFF CELLS AND ON DYE TRANSFER BETWEEN REAGGREGATED CELL PAIRS

The inhibitory effects of 12-O-tetradeconylphorbol-13-acetate (TPA) on the Lucifer Yellow leakage in single (nondissociated and dissociated) Novikoff cells in the presence of ethyleneglycotetraacetic acid (EGTA ) and transfer between reaggregated cell pairs were investigated Under treatment with TPA, single Novikoff cells showed inhibition of the dy e leakage in the presence of EGTA, especially after 60-min treatment. There were only slight differences between nondissociated and dissocia ted cells in these experiments. The dye transfer in reaggregated cell pairs were significantly inhibited after 30-min treatment with TPA. In pretreatment with TPA during the recovery period of reaggregation the dye transfer in cell pairs was completely blocked. It was suggested t hat TPA blocks the assembly of gap junction, while it had no remarkabl e effect on gating mechanisms of the hemichannels.