Chloroquine-induced inhibition of rat serum muramidase activity in vivo in relation to tissue changes

Chloroquine was tested for its inhibitory effect in vivo on the activities of rat serum and tissue muramidase. Daily administration of this anti-malarial drug to rats resulted in an appreciable reduction of kidney and liver enzyme activities 1 day after the first dose. No corresponding increases in enzyme activity were detected in the serum of treated animals up to day 9 when muramidase activity was then significantly reduced. Activity observed in the heart tissue was not affected until day 12, when the level was significantly reduced. These results suggest that chronic chloroquine administration to rats may result in an extensive inhibition of muramidase activity probably at the cellular/molecular level.