Insulin release in cystic fibrosis.

Early insulin response to rapid intravenous injection of glucose was studied in 7 cases of cystic fibrosis aged 8 months to 9 1/2 years. Plasma insulin was measured with a radioimmunological method. Blood glucose values were determined and the glucose disappearance rate (kG) calculated. In all children except the youngest one the early insulin response values were low compared with normal children. The kG-values were normal and correlated neither to the duration of clinical symptoms, nor to the patients' actual clinical condition measured by means of the Shwachman score. The explanation of the decreased insulin response is probably the progressive fibrosis of the pancreas. This may also explain the reported increased incidence of diabetes mellitus in cystic fibrosis. Comparison is made with the condition in pancreatic fibrosis in rabbits, produced through duct ligation.