[Concentration of different forms of RNA in the brain and ribonuclease activity of the nuclear, ribosomal and supernatant fractions of brain tissue following the action of cyclic adenosine-3',5'-monophosphate and S-adenosyl-L-methionine].

Quantitative changes of various forms of ribonucleic acids [nuclear (n-RNA), ribosomal (r-RNA), transport (t-RNA)] as well as ribonuclease activity have been studied in rat brain, in its nuclear, ribosomal and supernatant fractions following 3,5-cyclic AMP (c-AMP) and S-adenosyl-L-methionine. These substances were shown to raise the levels of r-RNA in brain and reduce the amount of n-RNA of GC type. c-AMP was also found to reduce the n-RNA of AU type and t-RNA in brain, while S-adenosyl-L-methionine does not affect n-RNA of AU type and raises considerably t-RNA. S-adenosyl-L-methionine has been found to raise the levels of all kinds of RNA while c-AMP has no effect. Ribonuclease activity of nuclear, ribosomal and supernatant fractions (105,000 g) of brain has been found to be enhanced by c-AMP while S-adenosyl-L-methionine raises ribonuclease activity of ribosomal fraction only at pH 7.9. The data obtained indicate that c-AMP and S-adenosyl-L-methionine are of importance in the mechanisms regulating the level of nucleic acids and activity of enzymes involved in their metabolism.