The effect of chloroquine on the uptake of 3H-oestradiol by the uterus and other tissues of the rat.

Adult virgin albino rats were ovariectomized for 10 days and were thereafter administered a daily dose of chloroquine diphosphate (12 mg/kg rat weight) in aqueous solution. This 'chronic dose' produced a significant enhancement of 3H-oestradiol uptake by the uterus and an inhibition of uptake by the liver of the rats. These effects were not observed when the chloroquine was administered only on 1 day ('acute dose') which corresponded to the last day of the 8-day treated rats. Chloroquine, in either regimen, was found to have no significant effect on oestradiol uptake by the kidney or gastrocnemius muscle. These results suggest that chronic chloroquine treatment may lead to an alteration of oestradiol binding and action in its target organs.