Intracellular diffusion of oxygen and hypoxic sensing: Role of mitochondrial respiration

Abstract

In vivo, diffusional O2 gradients from the capillary blood to the intracellular space determine O2 availability at the O 2 sensing molecules in the cell. With a novel technique for imaging intracellular O2 levels using green fluorescent protein (GFP), we examined the possibility that diffusional O2 concentration gradients might be involved in the cellular hypoxic sensing in cultured Hep3B cells. In the present study, we failed to demonstrate significant gradients of intracellular O2 when mitochondrial respiration was maximally elevated by an uncoupler of oxidative phosphorylation. Thus, we conclude that intracellular O2 gradients may be negligible at normal mitochondrial O2 demand in these cells. © Springer Science+Business Media, LLC 2010.