Inhibition of cell growth in vitro by adenosine 3',5'-monophosphate

Adenosine 3',5'-monophosphate, at a concentration of 40 micrograms per milliliter, inhibits the growth of HeLa and strain L cells in culture. The inhibition becomes progressively greater during the incubation of the cells. Adenosine 5'-monophosphate and adenosine, metabolites of adenosine 3',5'-monophosphate, do not affect the growth of either cell culture. This suggests that 3',5'-monophosphate enters the cell without alteration. Dibutyryl-adenosine 3',5'-monophosphate, reported to have a greater activity than adenosine 3'5'-monophosphate on several tissues, inhibited the growth of the cells much less.