Insulin Metabolism in Hypothalamic Obesity

Summary

Serum C-peptide and Immunoreactive Insulin (IRI) level was measured during per os glucose tolerance test as well as fasting specific insulin binding percentage and capacity of erythrocytes in hypothalamic obesity and in obese children due to hypercalorization, and was compared with ideal-weight controls. Integral values of curves (Σ) and ΣC-peptide/ΣIRI ratios were calculated. In 4 cases fasting C-peptide content was substantially increased as compared to the other groups. The data suggest that hyperinsulinism in diencephalic obesity is primary. The ratio of the two peptides was normal or increased; insulin binding % of erythrocytes corresponded to that of the control group, which explains in these cases normal or favourable glucose metabolism. It is thought that in obese children high fasting C-peptide levels with an adequate clinical picture can indicate the functional examination of the hypothalamic-pituitary system. ΣC-peptide/ΣIRI ratio differing from normal indirectly shows the changes of receptor function.

Key words

Hypothalamic obesity - C-peptide - Immunoreactive insulin - Insulin receptor