Tolbutamide and glyburide differ in effectiveness to displace alpha- and beta-adrenergic radioligands in pancreatic islet cells and membranes.
Diabetes
; 33(5): 499-503, 1984 May.
Article
in En
| MEDLINE
| ID: mdl-6327436
ABSTRACT
Previous in vivo findings indicated that alpha-adrenergic blocking agents enhanced tolbutamide-induced insulin secretion, whereas beta-blockade attenuated it. In the present study, the interaction of tolbutamide and glyburide with the rat islet adrenergic receptors is examined directly by determining the effectiveness of these drugs to displace the specific alpha- and beta-adrenergic radioligands, [3H]-clonidine and [3H]-dihydroalprenolol (DHA). It was found that both tolbutamide and glyburide had affinity constants for the adrenergic receptors that were similar to those for the natural receptor ligands and powerful antagonists. Tolbutamide displaced both alpha- and beta-radioligands but had a higher affinity at the beta-receptor. Glyburide also displaced radioligands from both types of receptors but had a higher affinity for the alpha-receptor. This study suggests that these two sulfonylurea hypoglycemic agents may affect insulin secretion by different mechanisms.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tolbutamide
/
Islets of Langerhans
/
Receptors, Adrenergic
/
Clonidine
/
Glyburide
/
Dihydroalprenolol
/
Alprenolol
Limits:
Animals
Language:
En
Journal:
Diabetes
Year:
1984
Type:
Article