JN: Effects of secretagogues and theophylline on canine gastric mucosal cyclic nucleotides
- RA Levine, EH Schwartzel, Jr., S Bachman, -Talev
- J Lab Clin Med
The possibility that cyclic AMP in gastric juice is derived from plasma by simple clearance was evaluated. The effect of exogenous cyclic AMP administration (1 mg/min) on radioimmunoassayable cyclic AMP in plasma and gastric juice was studied in dog stomach during histamine (8–16 μg/kg/hr) infusion. Experiments were performed in vagally denervated fundic (Heidenhain) and in innervated gastric pouches. During infusion of cyclic AMP with histamine, plasma cyclic AMP concentration rapidly increased 500-fold. Simultaneously, gastric juice cyclic AMP levels decreased almost 50%. In contrast, dibutyryl cyclic AMP infusion increased gastric juice cAMP concentration 5-fold, suggesting that the gastric mucosa is more permeable to dibutyryl cyclic AMP. In Heidenhain pouch experiments the clearance of dibutyryl cyclic AMP into gastric juice was only 1.5% of the clearance of aminopyrine. It appears that plasma clearance of cyclic AMP fails to account for most of the cyclic AMP present in gastric juice.