title: High affinity binding of [125I-Tyr11]somatostatin-14 to human small cell lung carcinoma (NCI-H69).
abstract: The in vitro binding of [125I-Tyr11]somatostatin-14 (SRIF-14) to membranes prepared from cultured human small cell lung carcinoma (SCLC) cells (NCI-H69) has been characterized. Binding to SCLC was monophasic and of high affinity (Kd = 0.59 +/- 0.02 nM, n = 3). The estimated Bmax was 173 +/- 2.4 fmol/mg protein. Receptors were also present on solid NCI-H69 tumors grown in vivo in the athymic nude mouse. However, the concentration was only about 10% of that observed in cell culture. Biologically-active SRIF analogues were potent inhibitors of [125I-Tyr11]SRIF-14 binding, and an analysis of the pharmacological specificity indicated that the SCLC receptor was of the peripheral (e.g., non-neural) subtype. The presence of SRIF receptors on SCLC membranes may indicate that SRIF has a role in regulation of SCLC function.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D018288:Carcinoma, Small Cell / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010179:Pancreas / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D017481:Receptors, Somatostatin; D013004:Somatostatin / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D017981:Receptors, Neurotransmitter; D017481:Receptors, Somatostatin; D013004:Somatostatin