Effect of cyclic AMP on cells of experimental lymphatic leukemia L-5718

Abstract

The effect of cyclic AMP (cAMP), dibutyryl-cAMP, and theophylline (an inhibitor of phosphodiesterase, the enzyme converting adenosine-3′, 5′-monophosphate into adenosine-5′-monophosphate) on the intensity of proliferation (as reflected in the increase in the nucleic acid content in the culture), DNA synthesis (thymidine-H³ incorporation), and transplantation properties (ability to repopulatein vivo) of leukemic cells of strain L-5178 was studied. The experiments showed that cAMP in a concentration of 0.8 mM inhibits thymidine-H³ incorporation considerably, retards proliferation, and reduces the transplantability of the leukemic cells. Theophylline and dibutyryl-cAMP have comparatively weak ability to inhibit DNA synthesis and the proliferative activity and transplantation properties of the cells.