N metabolism and its modelling studied in rats using 15N-labelled wheat

Male albino rats (body weight 90 g) received a test ration with 15N-labelled wheat as protein source for 1 to 8 days. The 15N excess in urine, feaces, some organs, the remaining carcass and in the blood was determined in dependence on time. On the basis of two different pool models the N metabolism values could be calculated. Protein synthesis and disintegration rates calculated by means of the N- and 15N balances of the pool in the steady state of the pool labelling amounted to 252.9 mg N/day and 203.0 mg N/day, resp. The calculation based on the time-dependent curve of the daily 15N excretion in urine resulted in corresponding synthesis and disintegration rates of 197.0 mg N/day and 134.6 mg N/day, resp. (author)