Dear Ashish,

You asked an interesting question in terms of what metabolic intermediates can be exchanged between cells. Pyruvate, although it is an important intermediate in mitochondria, does not belong to the metabolites that are exchanged. But it does lives one cell to feed thee other, but after conversion to lactic acid. This is exactly how astrocytes feed neurons. Lactate as a source of energy is better than pyruvate because it has an extra hydrogen. In neurons, lactate is converted to pyruvate which is transported into mitochondria and the hydrogen is also transported into mitochondria via malate/aspartate shuttle. As an extracellular metabolite pyruvate cannot exist for long, this is because pyruvate is a ketoacid and therefore nonenzymatically reacts with hydrogen peroxide and is destroyed.

Many researchers add pyruvate to the cell's culturing media hoping for protection of their cells. It does protects, because it diminishes the content of H2O2 in the medium, which is often present in large quantity. Thus after 2-3 hours the concentration of pyruvate in the medium will be negligible or gone.

Thanks Alexander V Panov for your kind reply.

Adding to your comment on conversation of Pyruvate to lactate : I believe that apart from this extra C, it is easy metabolic currency to transport in comparison to pyruvate due to presence of different MCTs.

I agree pyruvate is not a metabolic intermediate which usually gets exchanged between cells But I am still excited to know if pyruvate can itself shuttle from mitochondria to cytosol directly even in one single cell itself not between the cells.

What would be the purpose for this shuttling?

Cross talk between Cytosol and mitochondria... like it is well known for glutamine.