Any metabolic event which results in the breakdown of an NAD molecule requires re-synthesis of NAD to maintain intracellular levels of this co-enzyme.
G6PD (glucose-6-phosphate dehydrogenase) is the key enzyme that maintains intracellular levels of NADPH [ 39].
11 16 Although glutamine production is increased in critically ill patients, it is not sufficient to maintain intracellular levels of glutamine in muscle.
Mitochondria are responsible for the modulation of calcium within neurons to maintain intracellular levels, particularly important for the maintenance of neuronal excitability.
Additional neural activity will lead to an increased demand for ATP, as membrane pumps are activated to maintain intracellular levels of signaling cations and transmitters.
In other work, we have found that some strains with increased K+ efflux take up higher levels of Rb+, presumably as a compensatory mechanism to maintain intracellular levels of K+ (Manlandro et al., 2005).
The authors showed that these gender-dependent differences were due to the incapacity of XY neurons to maintain intracellular levels of reduced glutathione: a prominent defense against oxidative stress.
As this enzyme is critical to maintain intracellular levels of glutathione that inactivates platinum species, this sequence guarantees non-compromised anti-tumour activity of carboplatin given on day 2 after indisulam (Owa T, Eisai Co Ltd, Japan; personal communication).
It has been reported that knockdown GLS2 (GLS) by siRNA increased ROS production and oxidative DNA damage in colon cancer cells and elevated GLS2 expression was necessary for cells to maintain intracellular levels of glutamate, α-ketoglutarate, GSH, and ROS (Hu et al. 2010, Suzuki et al. 2010).
Interestingly, intracellular NPC2 protein levels in IMCs were dramatically decreased during 48 h of culture (Fig 5E), indicating that the relatively low Npc2 mRNA transcript levels in IMCs (Fig 5C) were not sufficient for maintaining intracellular protein levels in freshly isolated IMCs.
