Springer Online Journal Archives 1860-2000
Summary The expression patterns of cytosolic and nuclear polyamine acetyltransferases were studied in normal and neoplastic growth processesin vivo andin vitro to evidentiate the roles played by these enzymes in cell proliferation. In regenerating liver, cytosolic spermidine/spermine N1-acetyltransferase showed similar augments of mRNA level and enzymatic activity during the prereplicative period (4–8 h), whereas spermidine N8-acetyltransferase activity increased later (24 h) when DNA synthesis was maximally enhanced. In fibroblasts continuously dividing, the messenger for spermidine/spermine N1-acetyltransferase rapidly accumulated after serum-stimulation. In cultured Morris hepatoma cells stimulated to logarithmic growth, spermidine N8-acetyltransferase activity remained at plateau for 1 day declining thereafter, while spermidine/spermine N1-acetyltransferase activity immediately decreased. In Yoshida AH-130 hepatoma cells transplanted in rat peritoneum, spermidine N8-acetyltransferase and spermidine/spermine N1-acetyltransferase activities rose, respectively, in concomitance with elevated proliferation-rate and quasi-stationary phase of growth. Since the expression of cytosolic and nuclear acetyltransferases underwent different temporal activation, an involvement of these enzymes in separate metabolic processes controlling normal and neoplastic growth may be suggested.
Type of Medium: