Myocardial nucleotide transport.

A thorough consideration of the evidence for striated muscle cell transmembrane nucleotide movement provides only equivocal support for adenine nucleotide specific translocation across cell membranes. It is obvious that nucleotide-derived adenosine is taken up into cells in preference to free adenosine, and it is important to understand why this is so. The potential importance of released nucleotides to cell regulation justify studies to determine the source and release mechanism.