Effects of sodium L-ascorbate, uracil, butylated hydroxyanisole and extracellular pH on junctional intercellular communication of BALB/c 3T3 cells.

: To study the mechanism of tumor promotion by different classes of urinary bladder promoters, the effect of sodium L-ascorbate, uracil and butylated hydroxyanisole (BHA) on junctional intercellular communication was examined in cultured BALB/c 3T3 cells using a dye-transfer method. In addition, since administration of sodium L-ascorbate and several other bladder tumor promoters is known to result in increased urinary pH, the effect of pH of the culture medium on intercellular communication was investigated. Results showed that under the present experimental conditions on the BALB/c 3T3 cells, BHA inhibited intercellular communication while sodium L-ascorbate and uracil did not. Intercellular communication was inhibited in proportion to the increase of medium pH after incubation of 4 h. Although further study is necessary to confirm the negative results of sodium L-ascorbate and uracil, these results suggest differences in the promoting mechanism(s) among these agents.