although when tested on fresh il tissue , 5'-guanylyl imidodiphosphate [ gpp ( nh ) p ] , a nonhydrolyzable analog of gtp , was substantially less active than gtp in stimulating adenylate cyclase activity in the presence of isoproterenol , gtp and gpp ( nh ) p each stimulated adenylate cyclase to the same degree after solubilization of il tissue previously treated with cholera toxin .
C0018353
gtp
C0018366
gpp ( nh ) p