Gluconeogenesis in infancy and childhood. II. Studies on the glucose production from alanine in three cases of persistent neonatal hypoglycaemia.

Gluconeogenesis was studied in 3 cases of persistent neonatal hypoglycaemia. In 2 of the cases the labelling of blood glucose after i.v. injection of 1415C-alanine was reduced. In these 2 patients only 1.3-5% of the injected radioactivity was recovered in blood glucose, compared with 10% in normoglycaemic patients. The labelling of glucose from 14C-glycerol, as studied in one case, was not reduced. In this patient the labelling of blood glucose from C-alanine was improved after subtotal resection of the pancreas, and with increasing age. By the time of the isotope studies the plasma insulin was normal in all patients, and no deficiency of glucagon secretion could be detected after stimulation with an alanine load. A quantitative amino acid analysis of plasma revealed a moderate increase of some of the glucogenic amino acids. The results were interpreted as a deficiency of gluconeogenesis, probably at the phosphoenolpyruvate carboxykinase or pyruvate carboxylase step.