Impact of a low glucose concentration on cellular output in neuronal differentiation. Cortical neuronal differentiation was performed on TSC2 +/+ and TSC2 −/− hES in either 25 mM or 5 mM glucose media. Cellular compositions were examined at day 80 using immunofluorescence (A) and flow cytometry (B) for the postmitotic marker HuC/HuD; neuronal marker TUJ-1 and glial marker GFAP (n = 1 for each differentiation). For HuC/HuD, no differences were observed in TSC2 +/+ cultures between the differentiations in high or low glucose as both media led to the generation of approximately 25% postmitotic neurons at day 80 and TSC2 −/− cells produced just under 20% HuC/HuD-positive neurons in 25 mM glucose media. However, lowering the glucose concentration to 5 mM nearly abolished the generation of postmitotic neurons in TSC2 −/− cultures. The opposite could be observed with regard to GFAP-positivity, which did not differ for TSC2 +/+ cultures in both media, whereas GFAP-positivity increased to nearly 95% in TSC2 −/− cultures kept at 5 mM glucose. No differences between cell lines and media were found for TUJ1, which was detected in approx. 95% of all cells in all cultures.