Rp-8-Br-cAMPS sodium is an analog of cAMP and an inhibitor of PKA. Rp-8-Br-cAMPS sodium occupies cAMP binding sites on PKA type I regulatory subunits, thereby preventing PKA dissociation and activation. Rp-8-Br-cAMPS sodium can be used in the study of tumors and retrovirus-induced immune deficiency. Rp-8-Br-cAMPS sodium also inhibits insulin secretion.