Monitor peptide binding sites are expressed in the rat liver and small intestine.
125I-monitor peptide binding was performed using frozen sections of the rat liver and gut and visualized using autoradiography. Saturable binding was observed in unidentified single cells in the liver and in the mucosa of the small intestine. Epidermal growth factor (EGF) and GTPgammaS did not inhibit 125I-monitor peptide binding indicating that the binding sites are not EGF receptors or G protein-coupled receptors. The liver binding site exhibited an affinity 3.7-4.4-fold higher than those in the small intestine. It has been established that intraluminal monitor peptide releases cholecystokinin from the small intestine. The present results indicate that monitor peptide may also have liver associated functions.
McVey
D C
DC
Department of Medicine, Duke University Medical Center and Veterans Affairs Medical Center, Durham, NC 27710, USA.
Romac
J M
JM
Clay
W C
WC
Kost
T A
TA
Liddle
R A
RA
Vigna
S R
SR
D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D002766:Cholecystokinin / Q000378:metabolism; D003001:Cloning, Molecular; D004815:Epidermal Growth Factor / Q000378:metabolism; D005768:Gastrointestinal Hormones / Q000235:genetics / Q000378:metabolism; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D007421:Intestine, Small / Q000737:chemistry*; D007457:Iodine Radioisotopes; D008099:Liver / Q000737:chemistry*; D010187:Pancreatic Hormones / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D018000:Receptors, Peptide / Q000302:isolation & purification*; D014359:Trypsin Inhibitor, Kazal Pancreatic / Q000235:genetics / Q000378:metabolism
D005768:Gastrointestinal Hormones; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D007457:Iodine Radioisotopes; D010187:Pancreatic Hormones; D018000:Receptors, Peptide; C504705:Spink1 protein, rat; C121922:monitor peptide receptor; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D014359:Trypsin Inhibitor, Kazal Pancreatic; D004815:Epidermal Growth Factor; D002766:Cholecystokinin