SAMP lyase and AMP deaminase activity in rat parenchymal and kupffer cells in hepatocarcinogenesis

SAMP lyase and AMP deaminase were determined in parenchymal and kupffer cells of rats fed either basal or carcinogen-enriched diets. Results were calculated on a U/mg protein and U/cell basis. Data indicated that although deaminase increased 1 1/2 to 2-fold in parenchymal cells on a U/mg protein and U/cell basis from rats fed carcinogen-enriched diets there was a greater increase in U/mg protein. In contrast, little to no increase was seen in kupffer cells. SAMP lyase, however, depicted a smaller increase in parenchymal cells of carcinogen-enriched diet fed rats, but a 4- to 5-fold elevation in kupffer cells regardless of whether the data were expressed in U/mg protein or U/cell. These data indicate that increased activity of AMP deaminase may be a result of resistance to degradation in parenchymal cells, whereas SAMP lyase elevations in kupffer cells may reflect an increase in enzyme concentration.