Response of HT29 cells to butyrate depends on time of exposure and glucose deprivation.

The high level of alkaline phosphatase activity in HT29 cells induced after 2 or 5 days of butyrate treatment was decreased during their prolonged exposure (about 30 days) to this agent together with a decrease of sensitivity to apoptosis. However, an enormous additive effect on alkaline phosphatase activity was found after butyrate treatment of glucose-starved cells. In concert with this finding, the substructural analysis revealed a dense brush border, tendency to polarization and morphologically normal mitochondria. It can be concluded that prolonged butyrate treatment of HT29 cells attenuated their response to this agent. On the other hand, glucose deprivation, as another inductor of differentiation, was found to increase the sensitivity of HT29 cells to butyrate.