Effect of Nutrient Availability on Glucose Metabolism
To investigate the potential relationship with glucose metabolism,
analyses of extracellular metabolites (glucose, lactate,
O2, CO2) in the conditioned media
obtained from the final exchange cycle of the culture period were
conducted. Glucose consumption and lactate production (Table 1) followed
similar trends to the tissue formation results, with maximal
consumption/production occurring under intermediate media volumes (Table
1). Under low to intermediate media volumes (1 – 4 mL) metabolism was
primarily anaerobic as indicated by the high lactate-on-glucose yield
(YL/G) and relatively low magnitude of
O2 consumption and CO2 production (Table
1). However, larger media volumes (> 4 mL) appeared to
alter metabolism from primarily anaerobic to mixed aerobic-anaerobic
with a steep decline in YL/G as well as observed
increases in O2/CO2consumption/production (Table 1). Lastly, extracellular pH did not
follow a similar trend, but rather experienced monotonic increases
(alkaline) with increasing media volume (Table 1).