AMINO NITROGEN METABOLISM FOLLOWING ADMINISTRATION OF INDIVIDUAL AMINO ACIDS OR MEAT IN CONSCIOUS DOGS

¹ Department Physiology, University of Leeds, Leeds LS2 9JT

Normal conscious dogs were given a meal of meat or doses of individual amino acids by stomach tube. The concentration of amino nitrogen in systemic arterial plasma and the rate of urea production both increased; the magnitude and time course of these increases varied with the individual amino acid administered. There was a relationship between the plasma amino nitrogen concentration and urea production following L-serine, L-alanine, L-proline, dicarboxylic acids and L-cystine similar to that obtained after meat ingestion. It is suggested that these amino acids were transaminated as rapidly as they were absorbed to produce an increase in a general pool of amino acids. Following L-threonine, L-valine, D-serine and immediately after glycine, a small increase in urea production was accompanied by a large increase in plasma amino nitrogen concentration. It is suggested that these amino acids `escaped' transamination in the gut wall and liver and that the increase in plasma amino nitrogen was due to a high concentration of the individual amino acid administered.