title: Gluconeogenesis in infancy and childhood. I. A method for the study of the in vivo gluconeogenesis from alanine and glycerol.
abstract: The in vivo gluconeogenesis from alanine and glycerol in infants and children was studied by an isotope method, using 14C-labeled substates with subsequent separation of the radioactive compounds by thin-layer chromatography. Seven patients, aged 2 months to 2 years 11 months, with normal carbohydrate metabolism were studied. Trace amounts of [14C]alanine were injected intravenously in four fasting patients. The 14C moved quickly from alanine to lactate, with a peak activity in lactate obtained before 5 min. From 10 min on, the label disappeared rapidly from both. An equilibrium was established between alanine and lactate, displaced towards lactate. The peak activity in glucose was reached in 10-20 min, amounting to 10% of total injected activity. In one patient, who was also studied after a meal, the disappearance rate of alanine was reduced by 50%. Despite this reduction the appearance of label in lactate was increased, whereas the amount of label in glucose was much reduced. [14C]glycerol was injected intravenously in three fasting patients. In one patient, who received only a tracer dose of glycerol, 5 times more 14C appeared in glucose than in the patients studied with [14C]alanine. In two patients receiving a glycerol load together with the [14C]glycerol, the disappearance rate of glycerol was markedly reduced, as was the conversion of carbon to glucose and lactate.
mesh_terms: D000409:Alanine / Q000097:blood / Q000378:metabolism*; D001786:Blood Glucose / Q000378:metabolism; D002675:Child, Preschool; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D005215:Fasting; D005260:Female; D005943:Gluconeogenesis; D005990:Glycerol / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007773:Lactates / Q000097:blood; D008297:Male; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D007773:Lactates; D000409:Alanine; D005990:Glycerol