title: Homologous regulation of adenylate cyclase-coupled receptors for vasoactive intestinal peptide (VIP) on human mononuclear leucocytes.
abstract: The effect of agonists on VIP receptor regulation has been investigated in mononuclear human blood leucocytes. VIP receptor number and affinity, as well as VIP-stimulated cyclic AMP accumulation were measured after pretreatment with VIP, PHM-27 or secretin. Pretreatment for 30 min with 0.1 microM VIP caused 28% (S.E.M. = 15) reduction in specific binding, and 52% (S.E.M. = 12) reduction in cyclic AMP accumulation, while 3 h of pretreatment caused 59% (S.E.M. = 10) and 68% (S.E.M. = 12) reduction. Only VIP concentrations at the nanomolar level and higher were shown to have any effect. Bmax of the high-affinity receptor was reduced by 66% (S.E.M. = 8) after 30 min, and 95% (S.E.M. = 3) after 3 h of exposure to 0.1 microM VIP. No significant change was observed in receptor affinity, in Bmax of the low-affinity receptor, in ED50, or in ED100 of VIP-stimulated cyclic AMP accumulation. Pretreatment with PHM-27 (0.1 microM, 3 h) caused 24% reduction in [125I]VIP binding and 25% reduction in cyclic AMP accumulation, while no effect was detected after pretreatment with secretin (0.1 microM, 3 h).
authors.affiliation: Norwegian Defence Research Establishment, Division for Environmental Toxicology, Kjeller.
authors.forename: P
authors.initials: P
authors.lastname: Wiik
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000328:Adult; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism*; D008875:Middle Aged; D011964:Receptors, Gastrointestinal Hormone / Q000187:drug effects / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D000262:Adenylyl Cyclases