부산대학교 도서관

Inhibition of IGF-I action by circulating IGF-I receptor autoantibodies is a potential mechanism of IGF-I resistance in growing children. To define the prevalence of IGF-I receptor antibodies in short-statured children, we have examined serum and plasma samples from a well-characterized group of 34 short, prepubertal, growth hormone-sufficient children and three growth hormonedeficient children. IGF-I receptor purified from human placental membranes was radioiodinated by the solid phase radioiodination method. Serum from a patient with severe insulin resistance immunoprecipitated 28.9–44.7 of the 125I-labeled IGF-I receptor. The ranges (mean ± 3 SD) of 125I-labeled IGF-I receptor Immunoprecipitated by 1:10 diluted and by undiluted nonimmune human serum were 1.99 ± 0.63 and 4.42 ± 1.32, respectively. Immunoprecipitation of the 125I-labeled IGF-I receptor by eight samples from six children was > 3 SD above the mean when assayed at a 1:10 dilution. Nevertheless, when assayed undiluted, only one of these samples immunoprecipitated slightly more 125I-labeled IGF-I receptor than non-immune serum. We conclude from these data that immunoprecipitating autoantibodies to the IGF-I receptor are not commonly present in short-statured children.