Effects of dobutamine and terbutaline on adenylate cyclase activity and cyclic AMP content in the renal pelvis of rabbits.

We measured the adenylate cyclase activity and the cyclic AMP content of the upper and lower renal pelvis in rabbits in order to clarify whether cyclic AMP acted as the intracellular messenger of the response elicited by beta-agonists in renal pelvic smooth muscle. Adenylate cyclase activity was determined by the method of Salomon et al. and tissue cyclic AMP content by radioimmunoassay. Dobutamine elevated the adenylate cyclase activities and tissue cyclic AMP contents of the upper part of the renal pelvis more than those of the lower part of the renal pelvis. Terbutaline also elevated the adenylate cyclase activities and tissue cyclic AMP contents of both the upper and lower part of the renal pelvis. The terbutaline-induced increase was the same in the upper and lower pelvis. These data suggest that cyclic AMP acts as the intracellular second messenger in renal pelvic smooth muscle of rabbits. Furthermore it is thought that both beta 1- and beta 2-adrenergic receptors exist in rabbit renal pelvis and the distribution of these beta-receptor subtypes is different between the upper and lower part of the renal pelvis.