Glucose and glutamine-dependent metabolism in osteocytes and MYC- dependent osteogenic sarcoma cells. Doxycycline (20 ng/mL) was added to MYC- dependent osteogenic sarcoma cells and incubated for 48 hours. (a) Glucose and glutamine consumption along with lactate production was measured at six hours. N = 3 ± SEM * P<0.05 compared to 0 ng/ml doxycycline. (b) Cells were incubated in glutamine-free media for one hour. OCR was determined by injection of glutamine (4 mM). N = 5 ± SEM * P<0.05 compared to 20 ng/ml doxycycline. (c) Glucose and glutamine carbons feed into the TCA cycle. (d) and (e) Doxycycline was added to cells (0 or 20 ng/mL) and incubated for 48 hours and then labeled for six hours with either U13-Glucose or U13-Glutamine and subsequently citrate pools were examined. N = 3 ± SEM * P<0.05 compared to 0 ng/ml doxycycline.