beta-adrenoceptor density , ligand affinity , high-affinity agonist binding , basal adenylate cyclase activity and camp synthesis upon stimulation with either forskolin , f- , guanine nucleotides ( gtp or gppnhp ) or isoproterenol in the presence of the nucleotides were studied in membranes prepared from kidneys of young ( 2-3 month ) and old ( 24-25 month ) male wistar rats .
C0018328
guanine nucleotides
C0018353
gtp