[Endocrine function of the pancreas in tumors of the chiasmal-sellar region].

A clinicobiochemical study of 10 patients with tumors of the chiasmal sellar region and 8 healthy persons using the i. v. glucose tolerance test (IGTT) made it possible to reveal disorder of pancreatic alpha- and beta-cell function in the patients with tumors. A distinct picture of the chiasmal sellar process with the involved hypothalamus was clinically determined in all the patients. Radioimmunoassay of immunoreactive insulin, glucagon, C-peptide and glucose revealed fasting hyperinsulinemia in the presence of both hypo- and hyperglycemia. The latter was accompanied by a raised level of glucagon in the blood. The IGTT revealed in the patients with tumors of the chiasmal sellar region hyperreactivity of beta-cells and a decrease in the sensitivity of alpha-cells to glucose as well as glucose tolerance that may be both regarded as pathogenetic factors of the development of a prediabetic condition in such patients.