A simple assay for cyclic adenosine 3':5'-monophosphate in human saliva

Methods specially designed for the assay of cyclic adenosine 3':5'-monophosphate (cAMP) in human saliva have not previously been published. Methods for measurements in plasma or tissue preparations are inapplicable to saliva due to interference. This interference can be reduced by calibrating standard solutions with reagent blanks prepared from saliva pre-treated to remove cAMP (by charcoal adsorption). Further, human saliva contains only small amounts of cAMP (approximately 0.2 pmol/50 microliters saliva). The method presented provides the necessary sensitivity (lower detection limit: 0.02 pmol/50 microliters) obtained by adjustments of tracer and binding protein concentrations. The method is simple and has a comparatively great capacity for the number of test tubes to be assayed.