Glucose and glutamine utilization by rat lymphocytes, monocytes and neutrophils in culture: a comparative study

Abstract

Glucose and glutamine utilization and production of glutamate and lactate were determined for up to 48 h in lymphocytes, monocytes and neutrophils cultured in medium rich in metabolites and vitamins. Glucose was utilized by the three cell types in culture in the following order: neutrophils > monocytes > lymphocytes, whereas lactate was produced in the order: monocytes > neutrophils > lymphocytes. The consumption of glucose followed the activity of glucose-6-phosphate dehydrogenase but it was not related to hexokinase activity. Glutamine was consumed by the three leukocyte types in culture as follows: neutrophils > lymphocytes > or = monocytes. The consumption of glutamine was not fully related to the activity of phosphate-dependent glutaminase. The production of glutamate was not remarkably different among the three cell types. For comparison, glutamine and glucose utilization and glutamate and lactate production were also evaluated using 1-h incubated leukocytes. Under this condition, only glucose or glutamine was added to the medium. Glucose was utilized as follows: neutrophils > monocytes > lymphocytes, whereas lactate was produced in the following order: monocytes > or = neutrophils > lymphocytes. Glutamine was consumed as follows: neutrophils > lymphocytes > monocytes, whereas glutamate was produced as follows: neutrophils > or = monocytes = lymphocytes. The ratio of the amount of glucose/glutamine consumed by 1-h incubated cells was 0.5 for neutrophils, 1.5 for monocytes, and 0.3 for lymphocytes. However, the three cell types cultured for 48 h utilized glucose to a much higher degree than glutamine. The ratio of the amount of glucose/glutamine utilized by the cultured cells was 8.9 for neutrophils, 16.4 for monocytes, and 6.7 for lymphocytes. These observations support the proposition that glutamine is required in much higher amounts than glucose to accomplish the total metabolic requirement of leukocytes. Under conditions closer to physiological when the availability of a variety of metabolites and vitamins is not restricted, glucose is the preferred substrate for lymphocytes, monocytes and neutrophils.

Pyruvate-Dependent Changes in Neutrophil Amino- and Alpha-Keto Acid Profiles or Immunity: Which Mechanisms Are Involved?

“…The underlying thesis is, that in anabolic situations not only a raised pyruvate uptake, but also a substantial amount of de novo intracellular pyruvate as well as pyruvate-dependent metabolite synthesis occurs [37]- [39]. And indeed, our results seem to confirm this hypothesis, because following pyruvate incubation increased glutamate, glutamine, aspartate (asparagine), alanine, α-ketotglutarate but also to serine and glycine concentrations have intracellularly been found (i.e.…”

Nutrition, immune function and health of dairy cattle

“…Gln is characterized as a functional amino acid because it serves as a precursor for (1) purine and pyrimidine synthesis leading to DNA and RNA synthesis; (2) the production of NADPH for superoxide production in phagocytes; (3) oxidation for energy; and (4) nitric oxide production by macrophages (Newsholme et al, 1999;Furukawa et al, 2000;Pithon-Curi et al, 2004). To our knowledge, the fate of utilized Gln in bovine leukocytes has not been metabolically characterized.…”

“…Studies have shown that Gln is generally used by lymphocytes at high rates, well above requirements (i.e. .100-fold) for other metabolic processes, because of rapid cell division that is not observed in terminally differentiated cells such as PMN and macrophages (Newsholme et al, 1999;Pithon-Curi et al, 2004).…”

Use of cyanobacterial gas vesicles as oxygen carriers in cell culture

“…For proper demonstration of the beneficial effects associated with the improved oxygen carrying capacity in GV-supplemented medium, it was important that cell growth was not limited by any factor other than the availability of oxygen to the (2) accumulation of inhibitory metabolites such as lactate (Nahapetian et al 1986;Pithon-Curi et al 2004) and ammonia (Imamura et al 1982;Thilly et al 1982;Wong et al 2004). These were carefully eliminated in the perfusion culture study, as described in the following: The circulating medium was changed every 2 days.…”