In this study we characterized calcitonin (CT) receptors in human neuroblastoma IMR 32 cells. Saturation binding assays indicated that [125I]-human CT bound with high affinity to IMR 32 cell membranes (K(d)=253.6 pM; B(max)=3.84 fmol/mg protein). In competition binding studies, human adrenomedullin displayed high affinity for these sites (IC50=30 nM) whereas human α calcitonin-gene related peptide (αCGRP; IC50=145 nM) and human amylin (IC50=415 nM) showed lower affinity. These peptides increased cAMP levels in viable cells; the relative potencies were: human CT > human adrenomedullin > human αCGRP ≥ human amylin. The expression of mRNA coding for the published sequences of the human calcitonin receptor and of the human calcitonin receptor-like receptor was evaluated by reverse transcriptase- polymerase chain reaction. Electrophoretic analysis did not confirm the occurrence of mRNA coding for the above mentioned receptors in these cells. This study suggests the presence of a novel, putative CT receptor in IMR 32 cells. Copyright (C) 1999 Elsevier Science Ireland Ltd.

Characterization of a putative calcitonin receptor in IMR 32 human neuroblastoma cells

Spampinato S.;Cacciaguerra S.;Campana G.;Murari G.
1999

Abstract

In this study we characterized calcitonin (CT) receptors in human neuroblastoma IMR 32 cells. Saturation binding assays indicated that [125I]-human CT bound with high affinity to IMR 32 cell membranes (K(d)=253.6 pM; B(max)=3.84 fmol/mg protein). In competition binding studies, human adrenomedullin displayed high affinity for these sites (IC50=30 nM) whereas human α calcitonin-gene related peptide (αCGRP; IC50=145 nM) and human amylin (IC50=415 nM) showed lower affinity. These peptides increased cAMP levels in viable cells; the relative potencies were: human CT > human adrenomedullin > human αCGRP ≥ human amylin. The expression of mRNA coding for the published sequences of the human calcitonin receptor and of the human calcitonin receptor-like receptor was evaluated by reverse transcriptase- polymerase chain reaction. Electrophoretic analysis did not confirm the occurrence of mRNA coding for the above mentioned receptors in these cells. This study suggests the presence of a novel, putative CT receptor in IMR 32 cells. Copyright (C) 1999 Elsevier Science Ireland Ltd.
1999
Spampinato S.; Falcucci B.; Cacciaguerra S.; Campana G.; Murari G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/895804
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