Abstract
In vitro binding of 125I-insulin to erythrocyte and fibroblast surface receptors (IRB) was studied in a 3-year-old girl with L, her parents, and controls. At low insulin concentrations (0.1-2 ng/ml), both erythrocyte and fibroblast IRB were decreased relative to controls. Scatchard analysis of IRB showed a typical curvilinear profile for controls, but a linear function in the L patient, which paralleled the low-affinity IRB component in the parents at low insulin concentrations. Partially impaired IRB was demonstrated in the parents at low insulin concentrations. Erythrocyte IRB was 2.8 percent in the proband versus 3.6, 6.5, and 8.2 percent in the father, mother, and 24 adult controls, resp. Concanavalin A, which has been shown to inhibit high-affinity, low-capacity insulin receptors decreased IRB in the mother's cell and controls, but had no effect on erythrocyte IRB in the patient and her father. Stimulation by insulin of CH3-AIB transport was similar in control and L cells; however, stimulation of 2-deoxyglucose uptake and phosphorylation was impaired in L cells. Both the characteristics of erythrocyte and fibroblast IRB, as well as the resulting metabolic changes are consistent with a defective high-affinity, low-capacity insulin receptor, but intact low-affinity, high-capacity binding. We propose that this represents the molecular derangement basic to L.
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Elders, M., Elsas, L., Schedewie, H. et al. Correlation of metabolic parameters with high and low affinity insulin receptor binding in leprechaunism (L). Pediatr Res 15, 1566 (1981). https://doi.org/10.1203/00006450-198112000-00189
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DOI: https://doi.org/10.1203/00006450-198112000-00189