Characterization of specific insulin-like growth factor (IGF)-I and IGF-II receptors on cultured rabbit articular chondrocyte membranes.
The interaction of insulin-like growth factor (IGF)-I and IGF-II with specific type-I and -II receptor sites on rabbit articular chondrocyte membranes was studied. With labelled IGF-I as tracer, half-maximal displacement of the label was obtained with 1.4 ng IGF-I/ml and 22 ng IGF-II/ml. Using IGF-II as labelled peptide. 16 ng unlabelled IGF-II/ml and 200 ng IGF-I/ml were needed to inhibit the binding by 50%. Covalent cross-linking experiments revealed the presence of typical type-I (Mr 130,000 under reducing conditions) and type-II (Mr 260,000) receptor sites. In addition, with 125I-labelled IGF-II a very intense labelled band appeared at Mr greater than 300,000. This band was not found in mouse liver membranes and human placental membranes.
Jansen
J
J
University Hospital for Children and Youth, 'Het Wilhelmina Kinderziekenhuis', State University of Utrecht, The Netherlands.
van Buul-Offers
S C
SC
Hoogerbrugge
C M
CM
de Poorter
T L
TL
Corvol
M T
MT
Van den Brande
J L
JL
D000818:Animals; D001667:Binding, Competitive; D002358:Cartilage, Articular / Q000032:analysis*; D002462:Cell Membrane / Q000032:analysis; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D008970:Molecular Weight; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000302:isolation & purification*; D017451:Receptors, Somatomedin
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II