Time saving protein binding assay for the simultaneous determination of guanosine 3':5'-monophosphate (cGMP) and adenosine 3':5'-monophosphate (cAMP) in human urine.

A time-saving protein binding assay for the simultaneous determination of cGMP and cAMP has been adapted for human urine, using [3H]cGMP, [14C]cAMP, protein fractions from calf skeletal and lobster tail muscles and the phosphodiesterase inhibitor SQ 20.009. Recovery, accuracy, and precision are approximately at the 10% limit. Good specificity and no interference were observed with diluted urine samples (10 to 20 times).