Effects of Cyclic Adenosine 3',5'-Monophosphate and Insulin on Plasma Cell Tumor (MPC-11) in Culture

Abstract

Exogenous cyclic adenosine 3′,5′-monophosphate (cAMP) inhibits the growth of plasma cell tumor (MPC-11) in culture and the inhibition is entirely prevented by the addition of insulin to the culture medium (1). Opposite effects of cyclic AMP and insulin have been described in a number of nonneoplastic cells (2-6), a finding which prompted the search for biochemical effects altered in opposite directions by these two agents.Materials and methods. Cyclic AMP, N6-O2-dibutyryl adenosine 3′,5′-cyclic monophosphate (DBcAMP) and 5-adenosine monophosphate (AMP) were purchased from Sigma Chemical Company, adenosine from Schwarz/Mann, crystalline zinc porcine insulin (containing 0.002% glucagon) was a gift from Lilly Research Laboratory. Denatured insulin was prepared as described by Lotten and Sneyd (7). 14C-thymidine was purchased from Schwarz/Mann, 3H-leucine and 14C-inulin were obtained from New England Nuclear. The purity of all nucleotides and nucleosides was checked by thinlayer chromatography in several syst...