Changes in δ-aminolevulinate (ALA) synthetase and ALA dehydrase activities in liver and spleen of endotoxin-poisoned mice

Abstract

Mice were injected intraperitoneally with Salmonella typhimurium endotoxin to examine changes in the activity of δ-aminolevulinate (ALA) synthetase or ALA dehydrase, which palys an important role in initial steps of heme synthesis. A maximal decrease in the serum-iron level was observed 16hr after injection. The level returned to a normal range 48hr after injection.
The activities of ALA synthetase and ALA dehydrase decreased significantly in the liver 16hr after injection, but increase to a normal range about 32hr after injection. They also showed a transitory decrease in the spleen 16-24hr after injection, but increased thereafter. They were at higher levels during two weeks than those in the control mice. On the other hand, the blood ALA dehydrase level decreased markedly 1-2 days after injection.
The administration of pentobarbital in the endotoxin-poisoned mice resulted in an appreciable prolongation of time of sleep which had been induced by the drug in these mice. It was, therefore, assumed that the hepatic durg-metabolizing enzyme activity might have been affected with a decrease in the activities of hepatic ALA synthetase and ALA dehydrase in these mice.