C. Morens et al., Daily delivery of dietary nitrogen to the periphery is stable in rats adapted to increased protein intake, AM J P-ENDO, 281(4), 2001, pp. E826-E836
Citations number
48
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
Dietary nitrogen was traced in rats adapted to a 50% protein diet and given
a meal,containing 1.50 g N-15-labeled protein (HP-50. group). This group w
as compared with rats usually consuming a 14% protein diet and fed a meal c
ontaining either 0.42 g (AP-14 group) or 1.50 g (AP-50 group) of N-15-label
ed protein. In the HP group, the muscle nonprotein nitrogen pool was double
d when compared with the AP group. The main adaptation. was the enhancement
of dietary nitrogen transferred to urea (2.2 +/- 0.5 vs. 1.3 +/- .1 mmol N
/100 g body wt in the HP-50 and AP-50 groups, respectively). All amino acid
s reaching the periphery except arginine and the branched-chain amino acids
were depressed. Consequently, dietary nitrogen incorporation into muscle p
rotein was paradoxically reduced in the HP-50 group, whereas more dietary n
itrogen was accumulated in the free nitrogen pool. These results underline
the important role played by splanchnic catabolism in adaptation to a high-
protein diet, in contrast to muscle tissue. Digestive kinetics and splanchn
ic anabolism participate to a lesser extent in the regulation processes.