Effect of Qhloroquine on the Induction of Rat Uterine Peroxidase by an Oral Contraceptive

Abstract

Uterine peroxidase has been induced in immature female rate with estradiol and anovlar 21. Anovlar 21 is a steroid contraceptive containing 4 mg. norethisterone acetate (a progestin), and 0.O5 mg. ethinyl estradiol (an estrogen) per tablet. Maximum enzyme activity was found to occur 24 hours after oral administration of the contraceptive. The increased peroxidase activity caused by the cotrbined steroids was inhibited by the administration of cyclohexirrrLde and puromycin (inhibitors of protein biosgitheais). Peroxidase is thus synthesised de novo on the influence of the steroids. Chloroquine diphosphate has also been found to increase the activity of peroxidase, with the maximum activity occuring 18 hours after the drug has been injected intramuscularly. Cycloheximide has been found to prevent this stimulatory effect of chloroquine. Chloroquine was effective in increasing peroxidase activity in vivo over a dose range of 0-20 mg/kg. body weight. It however, did not affect peroxidase activity in vitro. Chloroquine potentiated uterine peroxidase induction by anovlar 21. Chloroquine and/or anovlar 21 prevented the production of litter by adult female rats.