Ac-Tyr1hGRF discriminates between VIP receptors from rat liver and intestinal epithelium.
The vasoactive intestinal peptide (VIP) stimulates adenylate cyclase activity in rat liver and intestinal epithelium with low and high efficacy, respectively. The human growth hormone releasing factor (hGRF) derivative with acetylated N-terminus e.g. Ac-Tyr1hGRF binds to VIP receptors in both tissues with a similar affinity. However, Ac-Tyr1hGRF is a partial VIP agonist with high intrinsic activity in liver (50% that of VIP) whereas it behaves as a VIP antagonist in intestine. These results further argue for a possible heterogeneity of VIP receptor-coupled adenylate cyclase among tissues on a pharmacological basis.
Rouyer-Fessard
C
C
Unité de Recherche sur la Différenciation et la Neuroendocrinologie de Cellules Digestives INSERM U178, Villejuif.
Couvineau
A
A
Voisin
T
T
Laburthe
M
M
D000262:Adenylyl Cyclases / Q000032:analysis; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D013007:Growth Hormone-Releasing Hormone / Q000031:analogs & derivatives / Q000378:metabolism*; D007421:Intestine, Small / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D008099:Liver / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D013007:Growth Hormone-Releasing Hormone; D000262:Adenylyl Cyclases