ESTRADIOL REDUCES INCORPORATION OF RADIOACTIVE SULFATE INTO CARTILAGE AND AORTAS OF RATS

Abstract

Sulfate labelled with S35 is readily incorporated both in vivo and in vitro into cartilage and aortas of rats. Estradiol benzoate (0.33 mg/day) administered subcutaneously for 3 weeks to adult male white rats results in a smaller quantity of labelled sulfate appearing in tne costal cartilage 24 hrs. after injection. Less sulfate was found in both cartilages and aortas of animals treated with estradiol after incubation of these tissues for 4 hrs. in vitro in Tyrode''s solution con-taining labelled sulfate. This effect of estradiol treatment on cartilage becomes apparent by 3 days and on aorta by 3 weeks. Tissues from hypophysectomized rats exnibited a similarly reduced sulfate incorporation in vitro following therapy for 4 days with estradiol. Testosterone proprionate (0.25 mg/day) injected into female rats for 3 weeks did not produce any observable effect upon the incorporation of sulfate. Experiments controlling food intake indicate that this effect of estradiol cannot be explained by differences in consumption of food. These findings indicate regulation by estrogens of incorporation of sulfate into mammalian connective and vascular tissues.