[Effect of neurohormone "C" on adenine nucleotide and adenosine metabolism in rat heart and brain].

Adenine nucleotides and adenosine are known to be of importance in the regulation of coronary function. This made a study of the effect of neurohormone "C" on the metabolism of adenine nucleotides and adenosine interesting in as much as neurohormone "C" dilates coronary vessels and has a direct metabolic effect on cardiac muscle. The results obtained have shown that incubation of cardiac muscle homogenates with labelled ATP increased the content of adenosine through raising 5'-AMP nucleotidase activity and inhibiting adenosine deaminase activity. In homogenates and slices of brain tissue the content of adenosine is, on the contrary, reduced. Opposite changes are observed in the content of AMP. The increase of adenosine in the heart by the increase of 5'-AMP nucleotidase activity and decrease of adenosine deaminase activity is probably, not the main factor of the coronarodilatatory effect of neurohormone "C". The reverse phenomena is noticed in brain, the functional significance of which must be studied. However, the role of adenosine in the mechanism of action of neurohormone "C" will become clear after in vivo experiments which are in progress.