preincubation of luteal membranes with human choriogonadotropin results in the formation of an activated state of adenylate cyclase which is not reversed by washing and which is limited only by the absence of guanine nucleotides , whereas preincubation with gtp yields only a partially activated adenylate cyclase which requires the presence of both gtp and human choriogonadotropin during assay to demonstrate maximal activity .
C0018328
guanine nucleotides
C0018353
gtp