[Cyclic nucleotides]

A survey of the available literature on the role of cyclic nucleotides (cyclic adenosine 3,5-monophosphate and cyclic guanosine 3,5-monophosphate) in the control over various aspects of cellular activity: regulation of growth and morphology of normal and tumorous cells, participation in differentiation of cells, blast-transformation, regulation of inflammatory and immunological processes governed by lymphocytes, is presented. A presumable mechanism of action of cyclic nucleotides is considered.