Development of Quantitative System for the Soluble Human IGF-II Receptor

• Published in: Clinical Pediatric Endocrinology Vol. 12; no. 1; pp. 31 - 38
• Main Authors: Takazawa, Yoshie, Harashima, Hiroko, Kojima, Masaaki, Hata, Toshio, Sasaki, Nozomu
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Society for Pediatric Endocrinology 2003
• Subjects: bodies to peptides of the soluble human IGF-IIR; competitive enzyme immunoassay; quantitative system for the soluble human IGF-IIR
• ISSN: 0918-5739; 1347-7358
• DOI: 10.1297/cpe.12.31

We have developed a quantitative system to measure serum concentrations of the soluble form of human IGF-II receptor (IGF-IIR). The soluble form retains the ability to bind to IGF-II and proteins with M6P moieties in circulating blood. IGF-IIR does not only control the degradation of IGF-II, but also inhibits DNA synthesis by modifying the IGF-II action. The measurement of serum concentrations of the soluble form is able to clarify the growth mechanism in vivo. The system employs an enzyme immunoassay (EIA) making use of antibodies to peptides 1103~1119 amino acid (AA) of IGF-IIR. We could obtain two single bands at about 220 kDa corresponding to the soluble form and at about 290 kDa corresponding to the cell membrane-associated form by Western blotting. According a recent report, the soluble form was 220 kDa, and the measured level was 700 ± 230 ng/ml in healthy adults. In our trial data, the measured mean level was about 724 ± 134 ng/ml in five healthy adults. These data were nearly coincident. Consequently this antibody has high specificity for the soluble form in blood and the cell membrane associated form of IGF-IIR.