title: Receptors for pituitary adenylate cyclase activating peptides in human pituitary adenomas.
abstract: The presence of pituitary adenylate cyclase activating polypeptide (PACAP) receptors coupled to adenylate cyclase was investigated in four types of human pituitary adenomas: three null adenomas and five gonadotropin-, three ACTH-, four GH-, and four PRL-producing adenomas. In all samples, except in prolactinomas, PACAP(1-27) and PACAP(1-38) stimulated adenylate cyclase activity equally well and potently (K(act) around 3 nmol). Vasoactive intestinal polypeptide (VIP) was systematically 100- to 300-fold less potent than both PACAPs. In prolactinomas, PACAP(1-27), PACAP(1-38), and VIP were inactive despite a response of the enzyme to guanosine 5'-triphosphate, Gpp(NH)p, forskolin, and fluoride. [125I-AcHis1]PACAP(1-27) binding was detected in all samples except in prolactinomas. In addition, a detailed analysis of receptors was feasible in all five gonadotropin- and in two ACTH-producing adenomas, confirming the existence of selective PACAP receptors that recognized PACAP(1-27) and PACAP(1-38) with similar high affinity (IC50 0.8-1.5 nmol) and VIP with a low affinity (IC50 100 nmol/L).
authors.affiliation: Department of Biochemistry and Nutrition, Erasme Hospital, Medical School, Université Libre de Bruxelles, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Robberecht
authors.forename: P
authors.initials: P
authors.lastname: Vertongen
authors.forename: B
authors.initials: B
authors.lastname: Velkeniers
authors.forename: P
authors.initials: P
authors.lastname: de Neef
authors.forename: P
authors.initials: P
authors.lastname: Vergani
authors.forename: C
authors.initials: C
authors.lastname: Raftopoulos
authors.forename: J
authors.initials: J
authors.lastname: Brotchi
authors.forename: E L
authors.initials: EL
authors.lastname: Hooghe-Peters
authors.forename: J
authors.initials: J
authors.lastname: Christophe
mesh_terms: D000236:Adenoma / Q000378:metabolism*; D000262:Adenylyl Cyclases / Q000378:metabolism; D001665:Binding Sites; D006801:Humans; D009479:Neuropeptides / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010911:Pituitary Neoplasms / Q000378:metabolism*; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: C495401:ADCYAP1 protein, human; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone; D014660:Vasoactive Intestinal Peptide; D000262:Adenylyl Cyclases