• The serum concentrations of insulin-like growth factors 1 and 2 (IGF-1 and IGF-2) were measured by specific radioimmunoassays in 25 nephrotic patients. The serum concentration of IGF-1 in nephrotic patients (mean±SEM, 169±17 ng/mL) was significantly lower than that observed in 20 control subjects matched for sex and age (338±36 ng/mL). The IGF-2 serum concentration was significantly lower in nephrotic patients (343 ±22 ng/mL) than in control subjects (898±80 ng/mL). The IGF-1 and IGF-2 150-kd and 45-kd carrier protein complexes were found in the urine of nephrotic patients, whereas there was no binding of radiolabeled IGF-1 or IGF-2 to IGF carrier proteins in the urine of control subjects. The low serum IGF-1 and IGF-2 levels observed in nephrotic patients could be partially due to the increased urinary losses of the IGF carrier proteins.
(AJDC. 1989;143:865-867)