Presence of highly selective receptors for PACAP (pituitary adenylate cyclase activating peptide) in membranes from the rat pancreatic acinar cell line AR 4‐2J

[摘要]

We characterized highly selective receptors for PACAP, the pituitary adenylate cyclase activating peptide, in the tumoral acinar cell line AR 4-2J derived from the rat pancreas. PACAP, a novel hypothalamic peptide related to vasoactive intestinal peptide (VIP), was tested as the full natural 38-residue peptide (PACAP-38) and as an N-terminal amidated 27-residue derivative (PACAP-27). The binding sites showed considerable affinity for [¹²⁵I]PACAP-27 (K _d =0.4 nM) and PACAP-38, while their affiity for VIP and the parent peptide helodemin was 1000-fold lower. These receptors were coupled to adenylate cyclase, the potency of PACAP-38 and PACAP-27 (K _act = 0.2 nM) being much higher than that of VIP (K _act= 100 nM) and helodemin (K _act = 30 nM). Chemical cross-linking of [¹²⁵I]PACAP-27 followed by SDS-PAGE and autoradiography revealed a specifically cross-linked peptide with an M _r, of 68000 (including 3000 for one PACAP-27 molecule).

[学科分类] 生物化学/生物物理

[关键词] Pituitary adenylate cyclase activating peptide receptor;Vasoactive intestinal peptide;Helodennin;Adenylate cyclase;Pancreatic acinar cell line AR 4-2J;(Rat);K d;concentration required for half-maximal inhibition of tracer binding to a given class of receptors;PACAP-38 and PACAP-27;pituitary adenylate cyclase activating peptides in full natural version (38 residues) and as an amidated N-terminal peptide (27 residues);VIP;vasoactive intestinal peptide;rat PHI and PHV;peptide histidine isoleucinamide (1-28) and peptide histidine valine (1-42) from rat;GRF;growth hormone releasing factor;CCK;cholecystokinin;EGF;epidermal growth factor;FGF;fibroblast growth factor;KIU;kallikrein inhibitor unit