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