Dynamic changes in glucose metabolism accompanying the expression of the neural phenotype after differentiation in PC12 cells

To assess what properties of glucose metabolism are most closely related to expression of the neural phenotype, some parameters of glucose metabolism in PC12 cells before (tumor-type) and after differentiation (neuron-type) were investigated. Neuron-type cells exhibited a 2.7-fold higher level of [ 3 H]DG retention than tumor-type cells, accompanied by a higher glucose transport rate and higher levels of hexokinase activity. [ 14 C]CO 2 production from [U- 14 C]glucose in neuron-type was also more than four-times greater than that in tumor-type cells. The levels of [ 14 C]carbon in macromolecules from [ 14 C]glucose in neuron-type cells were also much higher (10.6-fold) than those in tumor-type cells, and the levels of incorporation of [ 14 C]carbon were almost as high as those of [ 14 C]CO 2. From the metabolite analysis, amino acids appeared to be the major compounds converted from glucose. On the other hand, the uptakes of [ 35 S]methionine–[ 35 S]cysteine and [ 3 H]uridine in neuron-type cells were lower than those in tumor-type cells. Following depolarization with 50 mM potassium, [ 14 C]CO 2 production increased, but the retention of [ 14 C]carbon was not changed in neuron-type cells. The largest change accompanied by acquisition of the neural phenotype was carbon incorporation into the macromolecules derived from glucose. This property may be important for the expression of the neural phenotype as well as the higher levels of both glucose uptake and oxygen consumption.