Receptor binding of pancreatic spasmolytic polypeptide (PSP) in rat intestinal mucosal cell membranes inhibits the adenylate cyclase activity

• Published in: Regulatory peptides Vol. 16; no. 3; pp. 291 - 297
• Main Authors: Frandsen, Erik K., Jørgensen, Klavs H., Thim, Lars
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 30.12.1986; Amsterdam Elsevier
• Subjects: adenylate cyclase activity; Adenylyl Cyclase Inhibitors; Animals; Binding Sites; Biological and medical sciences; Cell Membrane - metabolism; cell membranes; Dose-Response Relationship, Drug; Female; Fundamental and applied biological sciences. Psychology; Gastrointestinal hormones; Gastrointestinal Motility - drug effects; inhibition; Intestinal Mucosa - metabolism; Male; Mucins; Muscle Proteins; Neuropeptides; pancreatic spasmolytic polypeptide (PSP); Peptides - metabolism; Peptides - pharmacology; rat intestinal mucosa; Rats; Rats, Inbred Strains; receptor binding; Trefoil Factor-2; Trefoil Factor-3; Vasoactive Intestinal Peptide - pharmacology; Vertebrates: digestive system; cell membranes; receptor binding; rat intestinal mucosa; inhibition; adenylate cyclase activity; pancreatic spasmolytic polypeptide (PSP); Vertebrata; Pancreatic hormone; Mammalia; Rat; Digestive system; Pancreatic spasmolytic polypeptide; Rodentia; Peptide hormone; Gut; Hormonal receptor
• ISSN: 0167-0115; 1873-1686
• DOI: 10.1016/0167-0115(86)90028-5

The recently isolated pancreatic spasmolytic polypeptide, PSP, interacted with specific binding sites in the gastrointestinal tract and inhibited the adenylate cyclase activity in rat intestinal mucosal cell membranes. The binding sites appeared to be heterogeneous and Scatchard analysis of the binding data indicated the presence of at least two classes of sites. The high-affinity low-capacity binding sites and the low-affinity high-capacity binding sites had apparent dissociation constants of 1.3 × 10 −7 mol/l and 4.2 × 10 −6 mol/l , respectively. The PSP induced inhibition of the adenylate cyclase activity was independent of the stimulatory state of the enzyme. The basal activity as well as that stimulated by VIP and secretin was half maximally inhibited at approximately 3 × 10 −5 mol/l of PSP. The inhibitory effect of PSP was independent of the agonist concentration employed. PSP did not affect the receptor binding of VIP nor did VIP affect the receptor binding of PSP.