Effect of metabolic stress on the expression of mTOR kinase in mouse liver cells.

The time course of changes in mTOR kinase protein and Akt and HSP70 molecular chaperone in hepatic cells was studied in a model system of metabolic stress (48-h food deprivation with subsequent restoration of normal volume of nutrition) on C57Bl/6 mice. The fluorescence intensity of mTOR protein stained with antibodies decreased in all liver cells during fasting. The expression of mTOR protein in different populations of liver cells was heterogeneous. The percentage of cells with initially high expression of mTOR protein decreased during 48-h food deprivation, while the percentage of cells with low mTOR expression increased. The levels of mTOR, Akt, and HSP70 returned to normal only on day 4 after normalization of nutrition.