The long-range goal of this research is to isolate and characterize all of the components necessary for reconstitution of hormonally regulated adenylyl cyclase system. Using the liver glucagon-sensitive adenylyl cyclase systems as a model system and by monitoring principally specific binding of labelled glucagon and adenylyl cyclase activity, we specifically propose during the next 5 years: (1) Purify the catalytic unit of the liver adenylyl cyclase system in a form that is either sensitive or insensitive to stimulation by nucleotide, and study its subunit composition. (2) Develop the necessary methodology to purify the glucagon receptor from liver and initiate its purification. (3) Identify and purify key regulatory components of the system: a Guanyl nucleotide regulatory component associated with the catalytic subunit using Gilman's reconstitution assays with membranes from AC- S49 lymphoma cells as means of identifying the component once separated from the catalytic subunit of the system; and b. Brain stimulatory factor(s). (4) Continue exploring the kinetics of this system with respect to nucleotide and hormone stimulation with the aim to further delineate its regulatory aspects and to identify possible additional components involved in normal functioning of adenylyl cyclases.