[en] The time course of the concentration of immunoreactive insulin (IRI) and C-peptide in the plasma and erythrocytes and the blood sugar level in GTT per os were investigated by means of radioimmunoassay. Altogether 73 healthy persons and 52 patients with a severe form of insulin-dependent diabetes mellitus were examined. To define the time course of changes in the concentration of the above values a rate gradient determined as a difference of changed concentration rate for the 1st and 2nd hour after load for each examined person, was proposed. The gradients of plasma IRI, plasma and erythrocytic C-peptide had maximum difference in healthy persons and patients. The hormone and blood sugar levels characterized the condition of the examined persons, and rate gradients were indicative of the state of the blood sugar regulation system