Intestinal and hepatic nitrogen balance in the rat after the administration of an oral protein load.
The fate of a small oral dose of protein given to overnight-starved rats was studied. After 3 h, 62% of the protein amino acids had been absorbed. Most of the absorbed N went into the bloodstream through the portal in the form of amino acids, but urea and ammonia were also present. About one-quarter of all absorbed N was carried as lymph amino acids. The liver was able to take all portal free ammonia and a large proportion of portal amino acids, releasing urea. The hepatic N balance was negative, indicating active proteolysis and net loss of liver protein.
Fernández-López
J A
JA
Departament de Bioquímica i Fisiologia, Universitat de Barcelona, Spain.
Casado
J
J
Esteve
M
M
Rafecas
I
I
Argilés
J M
JM
Remesar
X
X
Alemany
M
M
D000596:Amino Acids / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D007408:Intestinal Absorption / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008196:Lymph / Q000378:metabolism; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D011168:Portal System / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014508:Urea / Q000378:metabolism
D000596:Amino Acids; D004044:Dietary Proteins; D000641:Ammonia; D014508:Urea; D009584:Nitrogen