Uptake of ATP by liver and kidney in vitro.

Rat liver and kidney slices were incubated at 37 degrees C for 1 h in 1.0 ml of Krebs-HCO3 buffer containing 10mM glucose and one of the following: 5 mM [8-14C]ATP, 5 mM [8-14C]ADP, 5 mM [8-14C]AMP, or 5 mM [8-14C]ation medium and tissue extract were subjected to electrophoretic separation and the radioactivity present in ATP, ADP, AMP, IMP, inosine, adenosine, and hypoxanthine was counted. Extensive degradation of the added nucleotide was observed in the presence of both tissues. The concentrations of 14C-labeled ATP and ADP found in the liver and kidney indicated that these compounds were present within the cells. Evidence is presented which suggests that ATP, and to a lesser extent ADP, entered the liver and kidney as such and were not synthesized within the cell from 14C-labeled adenosine.