| Abstract: | Addition of AMP to cultures of Tetrahymena pyriformis caused an increase in glycogen content of the cells and a small inhibition of growth. Adenine, adenosine, ADP, and ATP also increased glycogen content. Inosine and GMP were less effective; cytidine and uridine were ineffective. The increase in glycogen content was also observed in cultures supplemented with ribose, fructose, or glycerol, and when glyconeogenesis was increased by partial anaerobiosis. Adenine itself did not serve as a glycogen precursor, nor could the lipids of the cell have been the source of the carbon for the increased glycogen. The specific activity of glycogen from cultures supplemented with labelled amino acids was lower in AMP-treated cells than in controls. AMP-treatment had little effect on 14CO2 production from labelled glucose, acetate, or pyruvate, but baused a marked inhibition of the oxidation of labelled glyoxylate. It was suggested that AMP increases the rate of glyconeogenesis from precursors other than amino acids and interferes with malate synthase activity or malate transfer from peroxisomes to mitochondria. |
