Effects of low molecular weight nutrients on the pattern of proteins synthesized by non-proliferating murine L cells

Abstract

When L cells are cultured for prolonged periods of time without a medium change, the rate of synthesis of two polypeptides (82 000 and 95 000 mol. wt) is greatly increased while that of two other polypeptides (85 000 and 56 000 mol. wt) is correspondingly decreased. These changes in protein synthesis pattern were previously shown [1] to be due to depletion of low molecular weight nutrients from the medium. The present study shows that although the medium is severely depleted of glucose and several amino acids, glucose depletion alone is solely responsible for induction of the observed phenomena. Increased synthesis of the 95 000 and 82 000 mol. wt polypeptides has been shown by other investigators to occur in a different cell system under conditions of glucose deprivation. The present study shows that the synthesis of two additional major cytoplasmic proteins, the 85 000 and 56 000 mol. wt polypeptides, is also glucose regulated.