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Metabolism and kinetics of parenterally administered ornithine and α-ketoglutarate in healthy and burned animals

1988; Elsevier BV; Volume: 7; Issue: 2 Linguagem: Inglês

10.1016/0261-5614(88)90033-7

1532-1983

Michel Vaubourdolle, A. Jardel, C. Coudray‐Lucas, Ohvanesse G. Ekindjian, J Agneray, Luc Cynober,

Muscle metabolism and nutrition

Abstract To improve our understanding of the metabolism of ornithine α-ketoglutarate (OKG), used as an adjuvant of parenteral nutrition, we studied the plasma kinetics, localisation of target tissues and metabolism of α ketoglutarate (αKG) and ornithine (Orn) in healthy and burned animals. After parenteral administration, the kinetics of plasma disappearance of the two labelled compounds showed a biphasic decrease reflecting an open two-compartmental model of elimination, with the exception of Orn in burned rats. The appearance of metabolites in the plasma was rapid, particularly with regard to glutamate, proline and, following ornithine administration, glutamine. This witnessed the engagement of the substrates in multiple metabolic pathways. The study of tissular distribution by autoradiography demonstrated certain target tissues in common for αKG and Orn such as the liver, intestinal mucosa, salivary glands, kidney and muscle. This is consistent with a possible synergic action of these two compounds. The identification of labelled amino-acids and aliphatic polyamines was also performed in the tissues. Two major observations were made, which could be of interest in further work concerning cellular mechanisms of OKG action. Firstly, after αKG administration, labelled Glu and αKG were detected simultaneously in muscle; this would render possible the local biosynthesis of the anticatabolic compound α ketoisocaproate. Secondly, the injection of 14 C-ornithine was followed by the appearance in the intestinal mucosa and salivary glands of labelled aliphatic polyamines, which possess an anabolic effect.