Metabolic responses to different glucose and glutamine levels in baby hamster kidney cell culture

In this work, a BHK21 clone producing a recombinant antibody/cytokine fusio n protein was used to study the dependence of cell metabolism on the glucos e and glutamine levels in the culture medium. Results obtained indicate tha t both glucose and glutamine consumptions show a Michaelis-Menten dependenc e on glucose and glutamine concentrations respectively. A similar dependenc e is also observed for lactate and ammonia productions. The estimated value of the Michaelis constant for the dependence of lactate production on gluc ose (K-Lac(Gla)) was 1.4 +/- 0.1 mM and for the dependence of ammonia produ ction on glutamine (K-Amm(Gln)) was 0.25 +/- 0.11 mM and 0.10 +/- 0.03 mM, at glucose concentrations of 0.28 mM and 5.6 mM respectively. At very low g lucose concentrations, the glucose to lactate yield decreased markedly, sho wing a metabolic shift towards lower lactate production. This metabolic shi ft was also confirmed by the significant increase in the specific oxygen co nsumption rate also observed at low glucose concentrations. Although it was highly dependent on glucose concentration, the oxygen consumption also inc reased with the increase in glutamine concentration. At very low glutamine concentrations, the glutamine to ammonia yield increased, showing a more ef ficient glutamine metabolism.