Relation of Iron Salts

I t has been previously reported (1) that brains of mice infected with the Theiler FA strain of mouse encephalomyelitis virus show marked inhibition in the rate of glucose phosphorylation. Since such impairment in the utilization of the most essential substrate of brain metabolism may be related to the neuron destruction in the course of the virus infection, its mechanism was investigated further. I t was at tempted first to clarify the mechanism by which the virus exerts its inhibitory effect and then to localize the site of action. I t has been found that all anomalies in brain metabolism observed either in the infected brain or in the normal brain to which virus preparations had been added, can be reproduced by the addition of small quantities of ferrous sulfate. Purified preparations of Theiler FA virus, after prolonged dialysis, were found to contain iron in sufficient amounts to account for the inhibitory action. The second part of this paper presents evidence showing that the glycolytic activity of a mouse brain homogenate which has been inactivated by the virus preparation or by ferrous sulfate, can be restored by the addition of a purified fraction obtained from rabbit muscle. This fraction also completely restores the glycolytic activity of the homogenate of a mouse brain infected with the Theiler FA virus. The "restoring factor" is destroyed at temperatures above 60°C. and is non-dialyzable. In all likelihood it represents the system on which the virus exerts its in vitro effect leading to impairment in glycolysis.