Glucagon            Opioids
Vasopressin (VP)            SRIF
LH, FSH, TSH         Angiotensin II
   ACTH           ACh (Ml
Epinephrine (P'S)      Epinephrine ( o(2)

t CAMP &

Fig. 6:  1984 model of adenylyl cyclase susceptible to both stimulatory and
inhibitory regulation through the respective heterotrimeric stimulatory (Ns,
now Gs) and inhibitory (Ni now Gi) regulatory components.  Each G protein was
shown to be under the control of a distinct set of receptors responsible for
distinct hormonal specificities exhibited by adenylyl cyclases from different
tissues and cells. (From Hildebrandt et al. 1984)