Abstract: A 75-85 Kd glycopolypeptide, capable of acting as a receptor for polypeptide of the bombesin type, is isolated from the surface of Swiss 3T3 cells. Certain antagonists and antibodies to the glycopolypeptide are described, the antagonists being of quite different structure to bombesin e.g. .differential.D-Pro.sup.2 [-spantide, .differential.D-Phe.sup.5 [-spantide and position 5 variants thereof. The antagonists and antibodies are of interest medically in that they are able to influence cell proliferation that occurs under the influence of the bombesin-like polypeptides.

Abstract: Oligopeptides have been found that antagonist cell proliferation stimulated not only by bombesin-like peptides but also other neuropeptides e.g. vasopressin and bradykinin. These oligopeptides block a broad family of mitogenic neuropeptides that bind to receptors that use the inositol signalling pathway and one such receptor has been identified. These oligopeptides are of particular interest in relation to small cell lung cancer.