Radioimmunoassay for human insulin-like growth factor-I receptor: applicability to breast carcinoma specimens and cell lines.
A radioimmunoassay for the human insulin-like growth factor-I (IGF-I) receptor was developed using a rabbit polyclonal antibody to the human IGF-I receptor and a highly purified IGF-I receptor. The purified receptor was radiolabeled with 125I-Bolton-Hunter reagent. Over 18% of the radiolabeled receptor was immunoprecipitated with the polyclonal antireceptor antibody. Purified IGF-I receptor concentrations as low as 5 ng/0.5 mL inhibited the radiolabeled IGF-I receptor binding. Purified insulin receptor weakly inhibited this binding, while the ligand IGF-I did not show inhibition. The radioimmunoassay was applicable to the measurements of IGF-I receptors in the Triton X-100 extracts of various tissues and cells. Breast cancer tissues and cells showed detectable IGF-I receptors, which correlated with IGF-I ligand binding. Receptor content was measurable in placenta and IM-9 cells, but receptor content was not measurable in liver and muscle extracts.
Pezzino
V
V
Cattedra di Endocrinologia, Università di Catania, Italy.
Milazzo
G
G
Frittitta
L
L
Vigneri
R
R
Ezaki
O
O
Kasahara
M
M
LeBon
T R
TR
Goldfine
I D
ID
Fujita-Yamaguchi
Y
Y
D001667:Binding, Competitive; D001943:Breast Neoplasms / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D011863:Radioimmunoassay / Q000379:methods*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017451:Receptors, Somatomedin; D014020:Tissue Extracts / Q000378:metabolism
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D014020:Tissue Extracts; D007334:Insulin-Like Growth Factor I