Isolation of adenosine 3′,5′-monophosphate and guanosine 3′,5′-monophosphate from rat urine

The carbon-nitrogen skeleta and the phosphate moieties of most nucleotides of mammalian bodies are excreted by the kidney as separate units, the non-phosphate portion usually appearing in degraded form. One exception is urinary excretion by man of an intact cyclic nucleotide, adenosine 3′,5′-monophosphate (3′,5′-AMP) ( Butcher and Sutherland, 1962). Earlier evidence had suggested presence of unidentified organic phosphate compounds in normal urine at a level approximating 1% of the total phosphate ( Rae, 1937). The existence of only a certain type of intact nucleotide in urine represents a selective biological behavior that may prove of interest in relation to rather general biochemical and biophysical characteristics of a system. This communication describes the finding of two cyclic nucleotides in the urine of Fisher rats.