Adaptation to restricted intake of protein and energy.
Adult rats that maintained nitrogen balance on a diet containing 5% casein fed ad libitum were restricted to 70% of their normal food intake for 31 days. This resulted in a negative N balance, loss of body weight and increased activities of hepatic glutamic pyruvic transaminase and arginase--all of which persisted for 10 days. After this time there was no further weight loss, the negative N balance returned to equilibrium and the activities of the two enzymes returned to normal indicating adaptation to the dietary restriction. Radio-isotope studies with labelled methionine showed that dietary restriction led to an increase in the radioactivity of the liver and a decrease of that of the muscles indicating maintenance of liver protein at the expense of muscle protein. Resting oxygen consumption decreased by 34% after 20 days of dietary restriction and this would account for the adaptation observed.
D000222:Adaptation, Physiological; D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D001119:Arginase / Q000378:metabolism; D001835:Body Weight; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism; D005508:Food Deprivation; D008099:Liver / Q000378:metabolism*; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D014176:Protein Biosynthesis; D051381:Rats
D004044:Dietary Proteins; D000410:Alanine Transaminase; D001119:Arginase; D009584:Nitrogen