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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1987-4-27
|
| pubmed:abstractText |
The beta-adrenergic and glucagon receptor-binding capacities in rat livers from 6-27 months of age were measured to investigate the mechanism of a previously observed rise in beta-adrenergic stimulated adenylate cyclase with increasing age. There was no concomitant increase in glucagon-stimulated adenylate cyclase. In the present study neither glucagon-binding capacity nor glucagon-stimulated adenylate cyclase changed with age. In contrast, the beta-adrenergic receptor capacity, measured in the same membranes by [125I]iodopindolol binding, increased nearly 3-fold from 6.6 +/- 0.6 fmol/mg at 6 months to 19.1 +/- 3.3 fmol/mg at 18-19 months. The increase was directly proportional to the maximum isoproterenol-stimulated adenylate cyclase activity in livers of rats up to 19 months of age. By 24-27 months the binding capacity had increased to 24.9 +/- 3.3 fmol/mg, but there was no further increase in adenylate cyclase activity. Thus, there appeared to be a beta-receptor-adenylate cyclase uncoupling in livers from the senescent animals (25-27 months). The defect could not be demonstrated by studies examining isoproterenol competition of [125I]iodopindolol from agonist-induced high affinity sites on the membranes, a procedure that examines receptor-Ns protein coupling. Activation of adenylate cyclase by the nonhormonal stimulators F- and forskolin did not change with age, indicating that the catalytic unit was not a limiting factor. Since the relationship between the glucagon receptor and adenylate cyclase also remained unaltered, the uncoupling apparently lies in an alteration of the interaction between the beta-adrenergic receptor and the guanine nucleotide-sensitive Ns protein.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
AIM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/3-iodopindolol,
http://linkedlifedata.com/resource/pubmed/chemical/Adenylate Cyclase,
http://linkedlifedata.com/resource/pubmed/chemical/Forskolin,
http://linkedlifedata.com/resource/pubmed/chemical/Glucagon,
http://linkedlifedata.com/resource/pubmed/chemical/Guanine Nucleotides,
http://linkedlifedata.com/resource/pubmed/chemical/Guanylyl Imidodiphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Isoproterenol,
http://linkedlifedata.com/resource/pubmed/chemical/Pindolol,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, beta,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Gastrointestinal Hormone,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Glucagon,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium Fluoride
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0013-7227
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
120
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
1534-41
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:3030705-Adenylate Cyclase,
pubmed-meshheading:3030705-Aging,
pubmed-meshheading:3030705-Animals,
pubmed-meshheading:3030705-Enzyme Activation,
pubmed-meshheading:3030705-Forskolin,
pubmed-meshheading:3030705-Glucagon,
pubmed-meshheading:3030705-Guanine Nucleotides,
pubmed-meshheading:3030705-Guanylyl Imidodiphosphate,
pubmed-meshheading:3030705-Isoproterenol,
pubmed-meshheading:3030705-Liver,
pubmed-meshheading:3030705-Male,
pubmed-meshheading:3030705-Pindolol,
pubmed-meshheading:3030705-Rats,
pubmed-meshheading:3030705-Rats, Inbred Strains,
pubmed-meshheading:3030705-Receptors, Adrenergic, beta,
pubmed-meshheading:3030705-Receptors, Gastrointestinal Hormone,
pubmed-meshheading:3030705-Receptors, Glucagon,
pubmed-meshheading:3030705-Sodium Fluoride
|
| pubmed:year |
1987
|
| pubmed:articleTitle |
Beta-adrenergic receptors, glucagon receptors, and their relationship to adenylate cyclase in rat liver during aging.
|
| pubmed:publicationType |
Journal Article,
Comparative Study
|