THE RELATIVE INCREASE IN METABOLISM OF THE LIVER AND OF OTHER TISSUES DURING PROTEIN METABOLISM IN THE RAT

Abstract

The rate of O consumption of rats fed on a diet containing 74% casein, and anesthetized with chloretone, was compared with that of controls fed on a diet containing no casein, immediately before and after ligating the blood supply of various regions of the body. The O consumption of the kidneys, in terms of O per min. per 100 sq. cm. of body surface, was practically the same in the 2 groups, although the total O intake of the former was 35% greater than the controls on low protein. Urinary secretion was not measured and no conclusions as to renal metabolism are drawn. The O consumption of the hind-quarters was only 8% greater in the rats on the high protein diet, while that of the abdominal viscera was 141% greater during protein than during carbohydrate feeding. At least 85% of the heat evolved as a result of the specific dynamic action of protein in chloretone-anesthetized rats is liberated in the abdominal viscera. It is concluded that the liver is probably the chief site, and possibly the only site, of the intermediary metabolism of those amino-acids which raise the metabolic rate, and that at least 80% of the specific dynamic action of these acids is due to the increased energy liberated by the hepatic cells during protein digestion.