[Vasoactive intestinal peptide receptor in a human pancreatic carcinoma cell line]

Vasoactive intestinal peptide (VIP) receptors were identified in a human pancreatic carcinoma cell line by radioreceptor assay, including time course, dissociation study, competitive inhibition, and cross reactions with secretin and glucagon, both of which are hormones of the same family. Peak binding of 125I-VIP to the cells occurred at 20-30 min at 37 degrees C. Displacement curve showed an increasing inhibition of binding with increasing concentration of unlabeled VIP(inhibited by 95% at 1 microM of VIP). KD of VIP receptors was 1.68 x 10(-10)M, and the number of binding sites was 3.6 x 10(5)/cell. It was also shown that VIP was able to induce cAMP production in this cell line, indicating that the VIP receptors in this cell line were biologically active.