Glucagon-like peptide-1 binding to rat hepatic membranes.
We have found [125I]glucagon-like peptide (GLP)-1(7-36)amide specific binding activity in rat liver and isolated hepatocyte plasma membranes, with an M(r) of approximately 63,000, estimated by cross-linking and SDS-PAGE. The specific binding was time- and membrane protein concentration-dependent, and equally displaced by unlabelled GLP-1(7-36)amide and by GLP-1(1-36)amide, achieving its ID50 at 3 x 10(-9) M of the peptides. GLP-1(7-36)amide did not modify the basal or the glucagon (10(-8) M)-stimulated adenylate cyclase in the hepatocyte plasma membranes. These data, together with our previous findings of a potent glycogenic effect of GLP-1(7-36)amide in isolated rat hepatocytes, led us to postulate that the insulin-like effects of this peptide on glucose liver metabolism could be mediated by a type of receptor probably different from that described for GLP-1 in pancreatic B-cells or, alternatively, by the same receptor which, in this tissue as well as in muscle, uses a different transduction system.
Villanueva-Peñacarrillo
M L
ML
Departamento Metabolismo, Nutrición y Hormonas, Fundación Jiménez Díaz, Madrid, Spain.
Delgado
E
E
Trapote
M A
MA
Alcántara
A
A
Clemente
F
F
Luque
M A
MA
Perea
A
A
Valverde
I
I
D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D005934:Glucagon / Q000378:metabolism*; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D007328:Insulin / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar
D007328:Insulin; D010446:Peptide Fragments; D010455:Peptides; C061970:glucagon-like peptide 1 (7-36); D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; C055454:glucagon-like peptide 1 (1-36)amide