A possible role for cyclic adenosine 3',5'-monophosphate in the regulation of acid secretion in the isolated stomach of guinea-pig.

1 The rate of acid secretion and mucosal cyclic adenosine 3',5'-monophosphate (cyclic AMP) content have been measured on the same guinea-pig isolated stomach preparation in response to histamine, theophylline and ICI 63197, a potent phosphodiesterase inhibitor. 2 Unstimulated control tissues had a spontaneous rate of acid secretion of 74.41 +/- 9.06 mumol H+/g wet wt. of mucosa per hour (s.e. mean, n = 20) and a cyclic AMP content of 0.517 +/- 0.058 mnol/g wet weight. 3 Each of the three drugs caused an increase in both the mucosal cyclic AMP content and the rate of acid secretion. These increases were inearly related to the logarithm of drug concentration for each drug. 4 There were no statistically significant differences between the three regression coefficients obtained for acid on drug and for cyclic AMP on drug. 5 There was a significant correlation between the rate of acid secretion and mucosal cyclic AMP content in stimulated preparations (P less than 0.001) and also in control preparations which received no drug (P less than 0.05). 6 These results are discussed in relation to the possible role of cyclic AMP in the mediation of acid secretory responses in the mammalian stomach.