The elevation of mouse thymus cell cyclic adenosine monophosphate (cAMP) by lipopolysaccharide

The ability of certain lipopolysaccharide (LPS) preparations to elevate cyclic adenosine monophosphate (cAMP) in mouse thymus cells in the presence of Ro 20-1724, 4-(3-butoxyl 4-methoxybenzyl)-2-imidazolidinone, was not related to the source of supply, bacterial strain, or method of extraction. Under the same conditions adenosine is a potent stimulator of thymus cell cAMP and is, of course, blocked by the further addition of theophylline. When theophylline was added to the LPS preparations with Ro 20-1724, the cAMP production was also blocked. These studies suggested that the observed stimulation of cAMP by LPS preparations was due to adenosine and/or its nucleotides present as contaminants.