[Kinetic parameters of protein metabolism in rats on protein-free diets].
16 male rats of 100 g live weight were given 50 mg of a mixture containing 15N labelled amino acids as a single dose within a protein-free feeding period. Following this the 15N excretion in faeces and urine as well as the development of the 15N excess in different organs and tissues were estimated over 3 days by slaughtering the animals within given 7 time intervals. Using a 3 pool model and the computer program for the interpretation of 15N tracer experiments by Töwe et al. (1984), kinetic parameters such as the rate of protein synthesis, protein breakdown and the rate of reutilization were calculated. Despite a negative N balance (-41.8 mg N/d) under protein-free conditions the protein metabolism of the rat shows high dynamics characterized by a high flux rate (225 mg N/d) and a high rate of body protein synthesis (181 mg/d). The reutilization was 85%. Depending on time the 15N excess in the tested organs and tissues showed significant differences and seems to demonstrate that under these conditions protein synthesis mainly takes place in the most important organs (e.g. intestinal tract, liver). Under protein-free feeding conditions protein synthesis and protein breakdown of the whole body seems to be slightly increased in comparison to N balanced feeding conditions.
Akademie der Landwirtschaftswissenschaften des DDR, Forschungszentrum für Tierproduktion Dummerstorf-Rostock Bereich Tierernährung Oskar Kellner.
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Krawielitzki
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Schadereit
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Wünsche
D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage*; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D009587:Nitrogen Isotopes; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains / Q000378:metabolism*; D012984:Software
D004044:Dietary Proteins; D009587:Nitrogen Isotopes; D011506:Proteins
Kinetische Parameter des Proteinstoffwechsels der Ratte bei proteinfreier Ernährung.