Studies on the valine sensitivity in non-ketotic hyperglycinemia
de Groot, C.J.; van den Berg, H.; Hommes, F.A.
Helvetica Paediatrica Acta 30(3): 247-254
1975
ISSN/ISBN: 0018-022X PMID: 1184395 Document Number: 92321
An oral load test with L-valine 100 mg/kg bodyweight in 3 patients with nonketotic hyperglycinaemia was accompanied by drowsiness and hyperreflexia. Metabolic studies revealed a slightly lower rate of disappearance of valine from blood in 2 of the patients. In the third patient the curve was the same as for controls. Gas chromatographic analysis for short-chain fatty acids in serum during the valine load test did not show increased concentrations. Urine collected during the test did not contain N-acylglycine derivatives. As the branched-chain amino acid transaminases were not inhibited by glycine, inhibition by glycine of the uptake of valine by the tissues was thought likely. Glycine was a competitive inhibitor of valine uptake in rat liver slices. It is concluded that the tendency for a decreased rate of valine disappearance from blood in nonketotic hyperglycinaemia could be due to an inhibition of valine uptake by the high plasma glycine concentration.