Retentissement de l'insuffisance rénale chronique sur les principaux acides du cycle tricarboxylique et métabolites voisins

The study of blood levels of the principal acids of the tricarboxylic acid cycle as well as pyruvic and lactic acids in patients suffering from chronic renal insufficiency shows that pyruvic acid and citric acid are normal, lactic acid is significantly lowered, while α-ketoglutaric acid, and especially malic acid are elevated. At the same time, the urinary elimination of citric and α-ketoglutaric acids, but not of malic acid, is strongly diminished. The changes in these blood levels are not related to modifications of the metabolic or excretory functions of the kidney. Neither are they explicable by variations in the acid-base equilibrium, nor by the degree of reduction of nicotinamide adenine dinucleotide. The role of enzymatic inhibitors, acting in particular upon malic dehydrogenase, does seem essential in the genesis of these changes.