Origin of cyclic adenosine monophosphate in saliva

The level of cyclic adenosine monophosphate (AMP) in duct saliva from the dog submandibular gland was increased after cyclic AMP was administered intravenously in vivo. Isoproterenol increased the level of cyclic AMP in plasma and saliva in vivo and in salivary gland slices in vitro, but increased the level only slightly in saliva in a prefused dog submaxillary gland.