Properties of vasoactive‐intestinal‐peptide receptors and β‐adrenoceptors in the murine radiation leukemia‐virus‐induced lymphoma cell line BL/VL3

Abstract

Based on radioligand binding and adenylate cyclase activation, functional receptors to vasoactive intestinal peptide(VIP)/helodermin, were shown to coexist with β2‐adrenoceptors and prostaglandin receptors in membranes from a cultured cloned BL/VL3 cell line of murine T‐cell lymphoma induced by a radiation leukemia virus. The relative potency of VIP‐related peptides to stimulate adenylate cyclase activity was: helodermin > VIP > peptide histidine isoleucinamide. Five VIP analogs inhibited 125I‐iodo‐VIP binding and stimulated adenylate cyclase activity, their decreasing order of potency being: VIP > [D‐Asp3]VIP > [D‐Ser2]VIP > [D‐Ala4]VIP = [D‐His1]VIP = [D‐Phe2]VIP. [D‐Phe2]VIP acted as a partial agonist (with an intrinsic activity of 0.1 as compared to that of VIP = 1.0) and competitively inhibited helodermin‐ and VIP‐stimulated adenylate cyclase activity with a similar Ki (0.07–0.10 μM). These data suggest the existence, in this murine T‐cell lymphoma, of VIP receptors of the ‘helodermin‐preferring’ subtype that are coupled to adenylate cyclase. Copyright © 1989, Wiley Blackwell. All rights reserved