| Abstract: | Patients with cystic fibrosis of the pancreas show an incidence of diabetes mellitus tenfold higher than is found in the general pediatric population. Considering this fact glucagon and insulin responses to oral glucose and intravenous arginine were studied in 22 CF children and adolescents. Some investigated patients had suffered from the disease for ten years and more. On the one hand the results show that pancreatic alpha cell function is normal. The kinetics of endogenous glucagon release are unaltered. On the other hand the data reveal that there is only a defect in the beta cell function consisting in a delayed insulin release selective to glucose whereas responsiveness to other stimuli for example tolbutamide and arginine is undisturbed. Furthermore there is a diminution in insulin-output to oral glucose as well as to intravenous arginine. Yet in patients with normal oral glucose tolerance endogenous insulin secretion is significantly reduced. Their regular carbohydrate tolerance may be a function of the patient's ability to maintain increased receptor numbers in the face of hypoinsulinemia. Despite greater quantities of secreted hormone a degree of relative peripheral insulin insensitivity has developed in the presence of hyperglycemia. This may be a consequence of impaired affinity of the specific target cell receptors. The insulin secretion pattern is proven to be identical to that of chemical diabetes mellitus in adults. Quantitative diminution in arginine stimulated insulin-output has been found to be independent of the degree of carbohydrate intolerance.(ABSTRACT TRUNCATED AT 250 WORDS) |
