Abstract
It is generally accepted that adenosine 3' 5'-cyclic monophosphate (cyclic AMP) is the intracellular mediator of the action of vasopressin in the urinary bladder of the toad. The hormone elevates the concentration of the nucleotide in the epithelial cells of this tissue and exogenous cyclic AMP, as well as the hormone elicits an increase in both net transport of sodium and permeability to water.
Recently it was reported that cyclic GMP stimulates sodium transport in toad bladder, does cyclic AMP, but in contrast to cyclic AMP, does not affect the permeability to water. This study was designed to confirm and extend these observations. Despite considerable effort, we have been unable to demonstrate stimulation of sodium transport by cyclic GMP in a convincing manner.
