Hormone‐stimulated GTPase activity in rat pancreatic plasma membranes

Physiological and Pharmacological Manipulations with Light Flashes

“…In particular, Annual Reviews www.annualreviews.org/aronline "caged GTP" could become an important tool for exploring biological processes thought to be rate-limited by GTPases. Increased GTP hydrolysis accompanies hormonal stimulation of adenylate cyclase in many tissues (24,55,62,68), and the GTPase step is thought to control the deactivation of adenylate cyclase (25,26). There are also several analogies between this adenylate cyclase system and the regulation of a phosphodiesterase by a GTPase in rod outer segments (41,69,88).…”

Cholera toxin inhibits prostaglandin E1 but not adrenaline‐induced stimulation of GTP hydrolysis in human platelet membranes

“…Hormonal factors which stimulate adenylate cyclase increase the activity of a high affinity GTPase, which appears to be an integrated part of the N-protein [3][4][5]. In several systems, cholera toxin has been shown to inhibit this hormone-induced GTPase stimulation [5][6][7].…”

Activation and attenuation of adenylate cyclase. The role of GTP-binding proteins as macromolecular messengers in receptor–cyclase coupling

“…Interestingly, incubation of turkey erythrocytes with 10-4M-isoproterenol results in a loss of both catecholamine-stimulated adenylate cyclase and GTPase activities but no decrease in receptor binding. GTPase activities sensitive to prostaglandin El (Bitonti et al, 1980), secretin and pancreozyminrelated peptides (Lambert et al, 1979) and glucagon (Kimura & Shimada, 1980) have now been observed in membranes from human mononuclear cells, rat pancreas and rat liver, respectively. In the case of the membranes from mononuclear cells (Bitonti et al, 1980), there is an apparently poor correlation Vol.…”