membranes that had been preincubated in the absence of guanine nucleotide and hormone showed a ; burst ' phase of cyclic amp synthesis when gtp was present in the assay incubation and a ; lag ' phase with p [ nh ] ppg ( guanosine 5'- [ beta , gamma-imido ] triphosphate ) present in the assay .
C0018328
guanine nucleotide
C0018353
gtp