Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In freshly collagenase-isolated rat pancreatic islets and in islets cultured for 72 hours, the effects of thiol reagents on glucagon (5 micrograms/ml) and/or glucose (16.7 mM)-mediated increases in cAMP formation as well as on clonidine (10 microM)-induced inhibition of these actions were studied. In freshly isolated islets and to a more pronounced degree in islets cultured for 72 hours glucagon (5 micrograms/ml) increased the cAMP content above the basal value. Clonidine (0.1-100 microM) had no significant effect on the basal cAMP formation, but inhibited the glucagon-mediated effect. The thiol reagents diamide (10-100 microM) and NEM affected neither the basal nor the glucagon-mediated effect, but abolished the inhibitory action of clonidine on cAMP formation. In freshly isolated islets, high glucose concentrations (8.3-16.7 mM) increased the cAMP formation. Diamide (100 microM) and NEM (100 microM) attenuated the stimulatory effect of 16.7 mM glucose. It is suggested that these selective effects of the thiol reagents on glucagon-mediated increase in cAMP formation in the presence of substimulatory concentration of glucose may be due to the differences in the sensitivity of the sulfhydryl groups of the G-proteins to thiol reagents i.e. Gi or proteins closely related to Gi being more sensitive than Gs. The data further suggest that glucose acts on the cAMP cascade at a step distinct from Rs. Since both glucose and glucagon effects were influenced by the addition of clonidine, it is possible to interpret the data as indicating that the effects of both stimulators eventually converge at some common step in the adenylate cyclase cascade.
 ...
PMID:Thiol reagents (diamide and N-ethylmaleimide) inhibit increase in cAMP in response to glucose and abolish the clonidine-mediated attenuation of glucagon-induced cAMP formation in isolated rat pancreatic islets. 196 19

In isolated rat pancreatic islets, the effect of diamide and N-ethylmaleimide (NEM) on forskolin- as well as on glucagon-induced elevation of cAMP was studied. Forskolin and glucagon increased cAMP levels in batch-incubated islets. Diamide and NEM further augmented forskolin-induced increase of cAMP levels, whereas glucagon-stimulated elevation of cAMP was not affected. From our data it is likely that under the conditions of the present study, the thiols related to the Ns-protein and the catalytic unit are insensitive to oxidation and alkylation. The potentiation of forskolin-induced cAMP production in intact islet cells by diamide and NEM may be due to inactivation of the thiols related to the Ni-protein.
 ...
PMID:Potentiation of forskolin-induced increase of cAMP by diamide and N-ethylmaleimide in rat pancreatic islets. 215 53