In vivo 14C Isotopic Evaluation of Amino Acid Oxidative Catabolism in the Growing Chick
- 1 January 1989
- journal article
- research article
- Published by S. Karger AG in Annals of Nutrition and Metabolism
- Vol. 33 (5) , 271-278
- https://doi.org/10.1159/000177545
Abstract
A single dose of [1–14C] or [U-14C]glycine or L-[1–14C] or [U-14C]valine was injected intraperitoneally into 1- and 3-week-old chicks. Continuous automatic determination of respiratory 14CO2 and determination of 14C in excreta and uric acid were carried out for 8 h. Computer-aided analysis of the kinetics of respiratory 14CO2 demonstrated two exponentially decreasing components, ‘fast 14CO2’ and ‘slow 14CO2’. Fast 14CO2production represents the immediate oxidation and/or decarboxylation of the 14C-labeled amino acid. The half-lives differed according to the nature of the 14C-labeled amino acid but not to the age of the chick. The size of the acetyl-CoA pool labeled by [14C]glycine was between 10 and 15 mmol/l00 g of chick. Metabolic partition of a circulating plasma free amino acid between oxidation and retention could be quantified by an isotopic index.Keywords
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