The human neuroblastoma cell line, IMR-32, expresses functional corticotropin-releasing factor receptors.
Corticotropin-releasing factor (CRF) receptors in IMR-32 human neuroblastoma cells were characterized after differentiation with 2.5 microM 5'-bromo-2'-deoxyuridine for 10 days. Scatchard analysis of [125I-Tyr0]ovine CRF binding revealed a high affinity binding site with a dissociation constant of 0.59 nM and a maximum binding capacity of 142 fmol/mg, the affinity of which was decreased by guanosine 5'-o-(3-thiotriphosphate). This binding was displaced in the following order of potency: human/rat CRF > ovine CRF > urotensin I > sauvagine > bovine CRF > [D-Phe12, Nle21,38, C alpha-MeLeu37]human/rat CRF-(12-41) > alpha-helical CRF-(9-41), indicative of the CRF1 receptor subtype. Functional coupling of this receptor was confirmed by CRF-induced increases in cyclic AMP, which were antagonised by alpha-helical CRF-(9-41) and [D-Phe12,Nle21,38,C alpha-MeLeu37] human/rat CRF-(12-41).
Merck Sharp and Dohme Research Laboratory, Neuroscience Research Centre, Harlow, Essex, UK.
J E
JE
Hogg
J
J
Myers
P H
PH
Hutson
D000818:Animals; D002417:Cattle; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D011869:Radioligand Assay; D018019:Receptors, Corticotropin-Releasing Hormone / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D007457:Iodine Radioisotopes; D018019:Receptors, Corticotropin-Releasing Hormone