Rapid changes in initiation-limited rates of protein synthesis in rat thymic lymphocytes correlate with energy charge

Depriving rat thymocytes of energy-providing substrates for 2 hr results in a 75–80% drop in rates of protein synthesis and a shift of ribosomes from active polysomes to inactive monomers and dimers. Glucose prevents these changes or, when added to starved cells, rapidly reverses them. Restoration of protein synthesis is associated with reversal of the 7% decline in the adenylate energy charge seen in starved cells. The data is consistent with the hypothesis that glucose increases initiation in starved cells, probably via effects on the balance of adenine nucleotides. Data with other substrates support this concept. The inability of glucose to fully restore energy charge in the presence of glucocorticoids or rotenone correlates with the limitation of protein synthesis.