Comparison of cAMP System in Parietal Cells from Rat and Guinea Pig

Adenylyl cyclase activity, cAMP content, and activation of cAMP-dependent protein kinase were measured in rat and guinea pig parietal cells isolated by the same procedure. Incubation of parietal cells with histamine resulted in aminopyrine uptake, stimulation of adenylyl cyclase activity, accumulation of intracellular cAMP, and activation of cAMP-dependent protein kinase. In addition, aminopyrine uptake and the cAMP system were stimulated in rat cells by epinephrine, whereas guinea pig cells were unresponsive to epinephrine. It is suggested that there may be differences between the two species with regard to receptors on the parietal cells.