Changes in Turnover Rates of Some Enzymes Involved in Nitrogen Metabolism in the Rat Liver after Administration of Carbon Tetrachloride

Publisher Website
Google Scholar
Abstract
Twenty-four hours after oral administration of CC14 to rats, the activity of their hepatic urea cycle enzymes, threonine dehydratase [EC 4.2.1.16], glutaminase [EC 3.5.1.2] and glutamine synthetase [EC 6.3.1.2] decreased in various amounts. No evidence was found that activator or inhibitor effects participated in these decreases. The serum level of glutamine synthetase at 24 hr was roughly equal to the value calculated using a kinetic model and assuming that the loss of the enzyme was due solely to leakage into the blood stream. The levels of other enzymes, however, amounted to only 3–8% of the calculated values. All of the enzymes which decreased markedly in the damaged liver, were induced effectively in intact rat liver through casein hydrolysate feeding, except for glutamine synthetase. Such an induction, however, failed to occur in rats treated with CC14. These results might suggest that the loss of activity is mainly caused by altered turnover rates of enzymes in the injured liver. Leakage appeared to play a major role only for glutamine synthetase.

This publication has 0 references indexed in Scilit: